From d0f5cf9b0cae76dd936935341eff0fa345e97c24 Mon Sep 17 00:00:00 2001 From: jongfoster <jongfoster@users.sourceforge.net> Date: Mon, 10 Sep 2001 19:00:25 +0000 Subject: [PATCH] Replacing text version of coding standards with a HTML one. This is a cosmetic change only. --- doc/STANDARDS.txt | 1134 --------------------------------- doc/standards.html | 1485 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 1485 insertions(+), 1134 deletions(-) delete mode 100644 doc/STANDARDS.txt create mode 100644 doc/standards.html diff --git a/doc/STANDARDS.txt b/doc/STANDARDS.txt deleted file mode 100644 index 705c33b4..00000000 --- a/doc/STANDARDS.txt +++ /dev/null @@ -1,1134 +0,0 @@ -@ Introduction - - -This set of standards is designed to make our lives easier. It is -developed with the simple goal of helping us keep the "new and -improved Junkbusters" consistent and reliable. Thus making -maintenance easier and increasing chances of success of the -project. - -And that of course comes back to us as individuals. If we can -increase our development and product efficiencies then we can -solve more of the request for changes/improvements and in general -feel good about ourselves. ;-> - - -@ Using Comments - - -@@ Comment, Comment, Comment - -@@@ Explanation: - -Comment as much as possible without commenting the obvious. For -example do not comment "aVariable is equal to bVariable". Instead -explain why aVariable should be equal to the bVariable. Just -because a person can read code does not mean they will understand -why or what is being done. A reader may spend a lot more time -figuring out what is going on when a simple comment or explanation -would have prevented the extra research. Please help your brother -IJB'ers out! - -The comments will also help justify the intent of the code. If the -comment describes something different than what the code is doing -then maybe a programming error is occurring. - -@@@ Example: - -/* if page size greater than 1k ... */ -if ( PageLength() > 1024 ) -{ - ... "block" the page up ... -} - -/* if page size is small, send it in blocks */ -if ( PageLength() > 1024 ) -{ - ... "block" the page up ... -} - -This demonstrates 2 cases of "what not to do". The first is a -"syntax comment". The second is a comment that does not fit what -is actually being done. - - -@@ Use blocks for comments - -@@@ Explanation: - -Comments can help or they can clutter. They help when they are -differentiated from the code they describe. One line comments do -not offer effective separation between the comment and the code. -Block identifiers do, by surrounding the code with a clear, -definable pattern. - -@@@ Example: - -/********************************************************************* - * This will stand out clearly in your code! - *********************************************************************/ -if ( thisVariable == thatVariable ) -{ - DoSomethingVeryImportant(); -} - - -/* unfortunately, this may not */ -if ( thisVariable == thatVariable ) -{ - DoSomethingVeryImportant(); -} - - -if ( thisVariable == thatVariable ) /* this may not either */ -{ - DoSomethingVeryImportant(); -} - -@@@ Exception: - -If you are trying to add a small logic comment and do not wish to -"disrubt" the flow of the code, feel free to use a 1 line comment -which is NOT on the same line as the code. - - -@@ Keep Comments on their own line - -@@@ Explanation: - -It goes back to the question of readability. If the comment is on -the same line as the code it will be harder to read than the -comment that is on its own line. - -There are three exceptions to this rule, which should be violated -freely and often: during the definition of variables, at the end -of closing braces, when used to comment parameters. - -@@@ Example: - -/********************************************************************* - * This will stand out clearly in your code, - * But the second example won't. - *********************************************************************/ -if ( thisVariable == thatVariable ) -{ - DoSomethingVeryImportant(); -} - -if ( thisVariable == thatVariable ) /*can you see me?*/ -{ - DoSomethingVeryImportant(); /*not easily*/ -} - - -/********************************************************************* - * But, the encouraged exceptions: - *********************************************************************/ -int urls_read = 0; /* # of urls read + rejected */ -int urls_rejected = 0; /* # of urls rejected */ - -if ( 1 == X ) -{ - DoSomethingVeryImportant(); -} - - -short DoSomethingVeryImportant( - short firstParam, /* represents something */ - short nextParam /* represents something else */ ) -{ - ...code here... - -} /* -END- DoSomethingVeryImportant */ - - -@@ Comment each logical step - -@@@ Explanation: - -Logical steps should be commented to help others follow the -intent of the written code and comments will make the code more -readable. - -If you have 25 lines of code without a comment, you should -probably go back into it to see where you forgot to put one. - -Most "for", "while", "do", etc... loops _probably_ need a -comment. After all, these are usually major logic containers. - - -@@ Comment All Functions Thoroughly - -@@@ Explanation: - -A reader of the code should be able to look at the comments just -prior to the beginning of a function and discern the reason for -its existence and the consequences of using it. The reader -should not have to read through the code to determine if a given -function is safe for a desired use. The proper information -thoroughly presented at the introduction of a function not only -saves time for subsequent maintenance or debugging, it more -importantly aids in code reuse by allowing a user to determine -the safety and applicability of any function for the problem at -hand. As a result of such benefits, all functions should contain -the information presented in the addendum section of this -document. - - -@@ Comment at the end of braces if the content is more than one screen length - -@@@ Explanation: - -Each closing brace should be followed on the same line by a -comment that describes the origination of the brace if the -original brace is off of the screen, or otherwise far away from -the closing brace. This will simplify the debugging, maintenance, -and readability of the code. - -As a suggestion , use the following flags to make the comment and -its brace more readable: - -use following a closing brace: - } /* -END- if() or while () or etc... */ - -@@@ Example: - -if ( 1 == X ) -{ - DoSomethingVeryImportant(); - ...some long list of commands... -} /* -END- if x is 1 */ - -or: - -if ( 1 == X ) -{ - DoSomethingVeryImportant(); - ...some long list of commands... -} /* -END- if ( 1 == X ) */ - - -@ Naming Conventions - - -@@ Variable Names - -@@@ Explanation: - -Use all lowercase, and seperate words via an underscore ('_'). -Do not start an identifier with an underscore. (ANSI C -reserves these for use by the compiler and system headers.) -Do not use identifiers which are reserved in ANSI C++. -(E.g. template, class, true, false, ...). This is in case -we ever decide to port JunkBuster to C++. - -@@@ Example: - -int ms_iis5_hack = 0; - -@@@ Instead of: - -int msiis5hack = 0; -int msIis5Hack = 0; - - -@@ Function Names - -@@@ Explanation: - -Use all lowercase, and seperate words via an underscore ('_'). -Do not start an identifier with an underscore. (ANSI C -reserves these for use by the compiler and system headers.) -Do not use identifiers which are reserved in ANSI C++. -(E.g. template, class, true, false, ...). This is in case -we ever decide to port JunkBuster to C++. - -@@@ Example: - -int load_some_file( struct client_state *csp ) - -@@@ Instead of: - -int loadsomefile( struct client_state *csp ) -int loadSomeFile( struct client_state *csp ) - - -@@ Header file prototypes - -@@@ Explanation: - -Use a descriptive parameter name in the function prototype in -header files. Use the same parameter name in the header file -that you use in the c file. - -@@@ Example: - -(.h) extern int load_aclfile( struct client_state *csp ); -(.c) int load_aclfile( struct client_state *csp ) - -@@@ Instead of: -(.h) extern int load_aclfile( struct client_state * ); or -(.h) extern int load_aclfile(); -(.c) int load_aclfile( struct client_state *csp ) - - -@@ Enumerations, and #defines - -@@@ Explanation: - -Use all capital letters, with underscores between words. -Do not start an identifier with an underscore. (ANSI C -reserves these for use by the compiler and system headers.) - -@@@ Example: - -(enumeration) : enum Boolean { FALSE, TRUE }; -(#define) : #define DEFAULT_SIZE 100; - -@@@ Note: We have a standard naming scheme for #defines that -toggle a feature in the preprocessor: FEATURE_xxx, where -xxx is a short (preferably 1 or 2 word) description. - -@@@ Example: - -#define FEATURE_FORCE 1 - -#ifdef FEATURE_FORCE -#define FORCE_PREFIX blah -#endif /* def FEATURE_FORCE */ - - -@@ Constants - -@@@ Explanation: - -Spell common words out entirely (do not remove vowels). - -Use only widely-known domain acronyms and abbreviations. Capitalize -all letters of an acronym. - -Use underscore (_) to separate adjacent acronyms and -abbreviations. Never terminate a name with an underscore. - -@@@ Example: - -#define USE_IMAGE_LIST 1 - -@@@ Instead of: - -#define USE_IMG_LST 1 or -#define _USE_IMAGE_LIST 1 or -#define USE_IMAGE_LIST_ 1 or -#define use_image_list 1 or -#define UseImageList 1 - - -@ Using Space - - -@@ Put braces on a line by themselves. - -@@@ Explanation: - -The brace needs to be on a line all by itself, not at the end of -the statement. Curly braces should line up with the construct -that they're associated with. This practice makes it easier to -identify the opening and closing braces for a block. - -@@@ Example: - -if ( this == that ) -{ - ... -} - -@@@ Instead of: - -if ( this == that ) { - ... -} - -or - -if ( this == that ) { ... } - -@@@ Note: In the special case that the if-statement is inside a loop, -and it is trivial, i.e. it tests for a condidtion that is obvious -from the purpose of the block, one-liners as above may optically -preserve the loop structure and make it easier to read. - -@@@ Status: developer-discrection. - -@@@ Example exception: - -while ( more lines are read ) -{ - /* Please document what is/is not a comment line here */ - if ( it's a comment ) continue; - - do_something( line ); -} - - -@@ ALL control statements should have a block - -@@@ Explanation: - -Using braces to make a block will make your code more readable -and less prone to error. All control statements should have a -block defined. - -@@@ Example: - -if ( this == that ) -{ - DoSomething(); - DoSomethingElse(); -} - -@@@ Instead of: - -if ( this == that ) - DoSomething(); - DoSomethingElse(); - -or - -if ( this == that ) DoSomething(); - -@@@ Note: The first example in "Instead of" will execute in a manner -other than that which the developer desired (per indentation). Using -code braces would have prevented this "feature". The "explanation" -and "exception" from the point above also applies. - - -@@ Do not belabor/blow-up boolean expressions - -@@@ Example: - -structure->flag = ( condition ); - -@@@ Instead of: - -if ( condition ) -{ - structure->flag = 1; -} -else -{ - structure->flag = 0; -} - -@@@ Note: The former is readable and consice. The later is wordy and -inefficient. Please assume that any developer new to the project has -at least a "good" knowledge of C/C++. (Hope I do not offend by that -last comment ... 8-) - - -@@ Use white space freely because it is free - -@@@ Explanation: - -Make it readable. The notable exception to using white space -freely is listed in the next guideline. - -@@@ Example: - -int firstValue = 0; -int someValue = 0; -int anotherValue = 0; -int thisVariable = 0; - -if ( thisVariable == thatVariable ) - -firstValue = oldValue + ( ( someValue - anotherValue ) - whatever ) - - -@@ Don't use white space around structure operators - -@@@ Explanation: - -- structure pointer operator ( "->" ) -- member operator ( "." ) -- functions and parentheses - -It is a general coding practice to put pointers, references, and -function parentheses next to names. With spaces, the connection -between the object and variable/function name is not as clear. - -@@@ Example: - -aStruct->aMember; -aStruct.aMember; -FunctionName(); - -@@@ Instead of: -aStruct -> aMember; -aStruct . aMember; -FunctionName (); - - -@@ Make the last brace of a function stand out - -@@@ Example: - -int function1( ... ) -{ - ...code... - return( retCode ); - -} /* -END- function1 */ - - -int function2( ... ) -{ -} /* -END- function2 */ - - -@@@ Instead of: - -int function1( ... ) -{ - ...code... - return( retCode ); -} -int function2( ... ) -{ -} - -@@@ Note: Use 1 blank line before the closing brace and 2 lines -afterwards. This makes the end of function standout to the most -casual viewer. Although function comments help seperate functions, -this is still a good coding practice. In fact, I follow these rules -when using blocks in "for", "while", "do" loops, and long if {} -statements too. After all whitespace is free! - -@@@ Status: developer-discrection on the number of blank lines. -Enforced is the end of function comments. - - -@@ Use 3 character indentions - -@@@ Explanation: - -If some use 8 character TABs and some use 3 character TABs, the code -can look *very* ragged. So use 3 character indentions only. If you -like to use TABs, pass your code through a filter such as "expand -t3" -before checking in your code. - -@@@ Example: - -static const char * const url_code_map[256] = -{ - NULL, ... -}; - - -int function1( ... ) -{ - if ( 1 ) - { - return( ALWAYS_TRUE ); - } - else - { - return( HOW_DID_YOU_GET_HERE ); - } - - return( NEVER_GETS_HERE ); - -} - - -@ Initializing - - -@@ Initialize all variables - -@@@ Explanation: - -Do not assume that the variables declared will not be used until -after they have been assigned a value somewhere else in the -code. Remove the chance of accidentally using an unassigned -variable. - -@@@ Example: - -short anShort = 0; -float aFloat = 0; -struct *ptr = NULL; - -@@@ Note: It is much easier to debug a SIGSEGV if the message says -you are trying to access memory address 00000000 and not -129FA012; or arrayPtr[20] causes a SIGSEV vs. arrayPtr[0]. - -@@@ Status: developer-discrection if and only if the variable is -assigned a value "shortly after" declaration. - - -@ Functions - - -@@ Name functions that return a boolean as a question. - -@@@ Explanation: - -Value should be phrased as a question that would logically be -answered as a true or false statement - -@@@ Example: - -ShouldWeBlockThis(); -ContainsAnImage(); -IsWebPageBlank(); - - -@@ Always specify a return type for a function. - -@@@ Explanation: - -The default return for a function is an int. To avoid ambiguity, -create a return for a function when the return has a purpose, and -create a void return type if the function does not need to return -anything. - - -@@ Minimize function calls when iterating by using variables - -@@@ Explanation: - -It is easy to write the following code, and a clear argument can -be made that the code is easy to understand: - -@@@ Example: - -for ( size_t cnt = 0; cnt < blockListLength(); cnt ++ ) -{ - .... -} - -@@@ Note: Unfortunately, this makes a function call for each and every -iteration. This increases the overhead in the program, because the -compiler has to look up the function each time, call it, and return a -value. Depending on what occurs in the blockListLength() call, it -might even be creating and destroying structures with each iteration, -even though in each case it is comparing "cnt" to the same value, over -and over. Remember too - even a call to blockListLength() is a -function call, with the same overhead. - -Instead of using a function call during the iterations, assign -the value to a variable, and evaluate using the variable. - -@@@ Example: - -size_t len = blockListLength(); - -for ( size_t cnt = 0; cnt < len; cnt ++ ) -{ - .... -} - -@@@ Exceptions: if the value of blockListLength() *may* change or could -*potentially* change, then you must code the function call in the -for/while loop. - - -@@ Pass and Return by Const Reference - -@@@ Explanation: - -This allows a developer to define a const pointer and call your -function. If your function does not have the const keyword, we -may not be able to use your function. Consider strcmp, if it -were defined as: - extern int strcmp( char *s1, char *s2 ); - -I could then not use it to compare argv's in main: - int main( int argc, const char *argv[] ) - { - strcmp( argv[0], "junkbusters" ); - } - -Both these pointers are *const*! If the c runtime library maintainers -do it, we should too. - - -@@ Pass and Return by Value - -@@@ Explanation: - -Most structures cannot fit onto a normal stack entry (i.e. they -are not 4 bytes or less). Aka, a function declaration like: - int load_aclfile( struct client_state csp ) - -would not work. So, to be consistent, we should declare all -prototypes with "pass by value": - int load_aclfile( struct client_state *csp ) - - -@@ Use #include <fileName> and #include "fileName" for locals - -@@@ Explanation: - -Your include statements should contain the file name without a -path. The path should be listed in the Makefile, using -I as -processor directive to search the indicated paths. An exception -to this would be for some proprietary software that utilizes a -partial path to distinguish their header files from system or -other header files. - -@@@ Example: - -#include <iostream.h> /* This is not a local include */ -#include "config.h" /* This IS a local include */ - -@@@ Exception: - -/* This is not a local include, but requires a path element. */ -#include <sys/fileName.h> - -@@@ Note: Please! do not add "-I." to the Makefile without a _very_ -good reason. This duplicates the #include "file.h" behaviour. - - -@@ Provide multiple inclusion protection - -@@@ Explanation: - -Prevents compiler and linker errors resulting from redefinition of -items. - -Wrap each header file with the following syntax to prevent multiple -inclusions of the file. Of course, replace PROJECT_H with -your file name, with "." Changed to "_", and make it uppercase. - -@@@ Example: - -#ifndef PROJECT_H_INCLUDED -#define PROJECT_H_INCLUDED - ... -#endif /* ndef PROJECT_H_INCLUDED */ - - -@@ Use `extern "C"` when appropriate - -@@@ Explanation: - -If our headers are included from C++, they must declare our -functions as `extern "C"`. This has no cost in C, but increases -the potential re-usability of our code. - -@@@ Example: - -#ifdef __cplusplus -extern "C" -{ -#endif /* def __cplusplus */ - -... function definitions here ... - -#ifdef __cplusplus -} -#endif /* def __cplusplus */ - - -@@ Where Possible, Use Forward Struct Declaration Instead of Includes - -@@@ Explanation: - -Useful in headers that include pointers to other struct's. -Modifications to excess header files may cause needless compiles. - -@@@ Example: - -/********************************************************************* - * We're avoiding an include statement here! - *********************************************************************/ -struct file_list; -extern file_list *xyz; - -@@@ Note: If you declare "file_list xyz;" (without the pointer), then -including the proper header file is necessary. If you only want to -prototype a pointer, however, the header file is unneccessary. - -@@@ Status: Use with discrection. - - -@ General Coding Practices - - -@@ Turn on warnings - -@@@ Explanation - -Compiler warnings are meant to help you find bugs. You should turn -on as many as possible. With GCC, the switch is "-Wall". Try and -fix as many warnings as possible. - - -@@ Provide a default case for all switch statements - -@@@ Explanation: - -What you think is guaranteed is never really guaranteed. The value -that you don't think you need to check is the one that someday will be -passed. So, to protect yourself from the unknown, always have a -default step in a switch statement. - -@@@ Example: - -switch( hash_string( cmd ) ) -{ - case hash_actions_file : - ... code ... - break; - - case hash_confdir : - ... code ... - break; - - default : - log_error( ... ); - ... anomly code goes here ... - continue; / break; / exit( 1 ); / etc ... - -} /* end switch( hash_string( cmd ) ) */ - -@@@ Note: If you already have a default condition, you are obviously -exempt from this point. Of note, most of the WIN32 code calls -`DefWindowProc' after the switch statement. This API call -*should* be included in a default statement. - -@@@ Another Note: This is not so much a readability issue as a robust -programming issue. The "anomly code goes here" may be no more than a -print to the STDERR stream (as in load_config). Or it may really be -an ABEND condition. - -@@@ Status: Programmer discretion is advised. - - -@@ Try to avoid falling through cases in a switch statement. - -@@@ Explanation: - -In general, you will want to have a 'break' statement within each -'case' of a switch statement. This allows for the code to be more -readable and understandable, and furthermore can prevent unwanted -surprises if someone else later gets creative and moves the code -around. - -The language allows you to plan the fall through from one case -statement to another simply by omitting the break statement within the -case statement. This feature does have benefits, but should only be -used in rare cases. In general, use a break statement for each case -statement. - -If you choose to allow fall through, you should comment both the fact -of the fall through and reason why you felt it was necessary. - - -@@ Use 'long' or 'short' Instead of 'int' - -@@@ Explanation: - -On 32-bit platforms, int usually has the range of long. On 16-bit -platforms, int has the range of short. - -@@@ Status: open-to-debate. In the case of most FSF projects -(including X/GNU-Emacs), there are typedefs to int4, int8, int16, (or -equivalence ... I forget the exact typedefs now). Should we add these -to IJB now that we have a "configure" script? - - -@@ Don't mix size_t and other types - -@@@Explanation: - -The type of size_t varies across platforms. Do not make assumptions -about whether it is signed or unsigned, or about how long it is. -Do not compare a size_t against another variable of a different type -(or even against a constant) without casting one of the values. -Try to avoid using size_t if you can. - - -@@ Declare each variable and struct on its own line. - -@@@ Explanation: - -It can be tempting to declare a series of variables all on one line. -Don't. - -@@@ Example: - -long a = 0; -long b = 0; -long c = 0; - -@@@ Instead of: - -long a, b, c; - -@@@ Explanation: -- there is more room for comments on the individual variables -- easier to add new variables without messing up the original ones -- when searching on a variable to find its type, there is less - clutter to "visually" eliminate - -@@@ Exceptions: when you want to declare a bunch of loop variables or -other trivial variables; feel free to declare them on 1 line. You -should, although, provide a good comment on their functions. - -@@@ Status: developer-discrection. - - -@@ Use malloc/zalloc sparingly - -@@@ Explanation: - -Create a local stuct (on the stack) if the variable will live -and die within the context of one function call. - -Only "malloc" a struct (on the heap) if the variable's life will -extend beyond the context of one function call. - -@@@ Example: - -If a function creates a struct and stores a pointer to it in a -list, then it should definately be allocated via `malloc'. - - -@@ The Programmer Who Uses 'malloc' is Responsible for Ensuring 'free' - -@@@ Explanation: - -If you have to "malloc" an instance, you are responsible for insuring -that the instance is `free'd, even if the deallocation event falls -within some other programmer's code. You are also responsible for -ensuring that deletion is timely (i.e. not too soon, not too late). -This is known as "low-coupling" and is a "good thing (tm)". You may -need to offer a free/unload/destuctor type function to accomodate -this. - -@@@ Example: - -int load_re_filterfile( struct client_state *csp ) { ... } -static void unload_re_filterfile( void *f ) { ... } - -@@@ Exceptions: - -The developer cannot be expected to provide `free'ing functions for -C run-time library functions ... such as `strdup'. - -@@@ Status: developer-discrection. The "main" use of this standard is -for allocating and freeing data structures (complex or nested). - - -@@ Add loaders to the `file_list' structure and in order - -@@@ Explanation: - -I have ordered all of the "blocker" file code to be in alpha -order. It is easier to add/read new blockers when you expect a -certain order. - -@@@ Note: It may appear that the alpha order is broken in places by -POPUP tests coming before PCRS tests. But since POPUPs can also -be referred to as KILLPOPUPs, it is clear that it should come -first. - - -@@ "Uncertain" new code and/or changes to exitinst code, use FIXME - -@@@ Explanation: - -If you have enough confidence in new code or confidence in your -changes, but are not *quite* sure of the reprocussions, add this: - -/* FIXME: this code has a logic error on platform XYZ, - * attempthing to fix - */ -#ifdef PLATFORM - ...changed code here... -#endif - -or: - -/* FIXME: I think the original author really meant this... */ - ...changed code here... - -or: - -/* FIXME: new code that *may* break something else... */ - ...new code here... - -@@@ Note: If you make it clear that this may or may not be a "good -thing (tm)", it will be easier to identify and include in the project -(or conversly exclude from the project). - - -@ Addendum: Template for files and function comment blocks: - - -@@@ Example for file comments: - -const char FILENAME_rcs[] = "$Id: STANDARDS.txt,v 1.4 2001/07/13 01:27:19 iwanttokeepanon Exp $"; -/********************************************************************* - * - * File : $S<!-- Break CVS Substitution -->ource$ - * - * Purpose : (Fill me in with a good description!) - * - * Copyright : Written by and Copyright (C) 2001 the SourceForge - * IJBSWA team. http://ijbswa.sourceforge.net - * - * Based on the Internet Junkbuster originally written - * by and Copyright (C) 1997 Anonymous Coders and - * Junkbusters Corporation. http://www.junkbusters.com - * - * This program is free software; you can redistribute it - * and/or modify it under the terms of the GNU General - * Public License as published by the Free Software - * Foundation; either version 2 of the License, or (at - * your option) any later version. - * - * This program is distributed in the hope that it will - * be useful, but WITHOUT ANY WARRANTY; without even the - * implied warranty of MERCHANTABILITY or FITNESS FOR A - * PARTICULAR PURPOSE. See the GNU General Public - * License for more details. - * - * The GNU General Public License should be included with - * this file. If not, you can view it at - * http://www.gnu.org/copyleft/gpl.html - * or write to the Free Software Foundation, Inc., 59 - * Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * - * Revisions : - * $L<!-- Break CVS Substitution -->og$ - * - *********************************************************************/ - - -#include "config.h" - - ...necessary include files for us to do our work... - -const char FILENAME_h_rcs[] = FILENAME_H_VERSION; - - -@@@ Note: This declares the rcs variables that should be added to the -"show-proxy-args" page. If this is a brand new creation by you, you -are free to change the "Copyright" section to represent the rights you -wish to maintain. - -@@@ Note: The formfeed character that is present right after the -comment flower box is handy for (X|GNU)Emacs users to skip the verbige -and get to the heart of the code (via `forward-page' and -`backward-page'). Please include it if you can. - -@@@ Example for file header comments: - -#ifndef _FILENAME_H -#define _FILENAME_H -#define FILENAME_H_VERSION "$Id: STANDARDS.txt,v 1.4 2001/07/13 01:27:19 iwanttokeepanon Exp $" -/********************************************************************* - * - * File : $S<!-- Break CVS Substitution -->ource$ - * - * Purpose : (Fill me in with a good description!) - * - * Copyright : Written by and Copyright (C) 2001 the SourceForge - * IJBSWA team. http://ijbswa.sourceforge.net - * - * Based on the Internet Junkbuster originally written - * by and Copyright (C) 1997 Anonymous Coders and - * Junkbusters Corporation. http://www.junkbusters.com - * - * This program is free software; you can redistribute it - * and/or modify it under the terms of the GNU General - * Public License as published by the Free Software - * Foundation; either version 2 of the License, or (at - * your option) any later version. - * - * This program is distributed in the hope that it will - * be useful, but WITHOUT ANY WARRANTY; without even the - * implied warranty of MERCHANTABILITY or FITNESS FOR A - * PARTICULAR PURPOSE. See the GNU General Public - * License for more details. - * - * The GNU General Public License should be included with - * this file. If not, you can view it at - * http://www.gnu.org/copyleft/gpl.html - * or write to the Free Software Foundation, Inc., 59 - * Temple Place - Suite 330, Boston, MA 02111-1307, USA. - * - * Revisions : - * $L<!-- Break CVS Substitution -->og$ - * - *********************************************************************/ - - -#include "project.h" - -#ifdef __cplusplus -extern "C" { -#endif - - ... function headers here ... - - -/* Revision control strings from this header and associated .c file */ -extern const char FILENAME_rcs[]; -extern const char FILENAME_h_rcs[]; - - -#ifdef __cplusplus -} /* extern "C" */ -#endif - -#endif /* ndef _FILENAME_H */ - -/* - Local Variables: - tab-width: 3 - end: -*/ - - -@@@ Example for function comments: - -/********************************************************************* - * - * Function : FUNCTION_NAME - * - * Description : (Fill me in with a good description!) - * - * Parameters : - * 1 : param1 = pointer to an important thing - * 2 : x = pointer to something else - * - * Returns : 0 => Ok, everything else is an error. - * - *********************************************************************/ -int FUNCTION_NAME( void *param1, const char *x ) -{ - ... - return( 0 ); - -} - - -@@@ Note: If we all follow this practice, we should be able to parse -our code to create a "self-documenting" web page. - - -@ Local variables for this standards file - - - -Local variables: -mode: outline -mode: auto-fill -outline-regexp: "[@]+" -tab-width: 3 -End: diff --git a/doc/standards.html b/doc/standards.html new file mode 100644 index 00000000..257c3825 --- /dev/null +++ b/doc/standards.html @@ -0,0 +1,1485 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> + <head> + <title>JunkBuster Coding Standards</title> + </head> + + <body> + <h1><a name="top"></a>JunkBuster Coding Standards</h1> + + <h1><a name="contents"></a>Contents</h1> + + <h3><a href="#s1">Introduction</a></h3> + + <h3><a href="#s2">Using Comments</a></h3> + + <ul> + <li><a href="#s3">Comment, Comment, Comment</a></li> + + <li><a href="#s4">Use blocks for comments</a></li> + + <li><a href="#s5">Keep Comments on their own line</a></li> + + <li><a href="#s6">Comment each logical step</a></li> + + <li><a href="#s7">Comment All Functions Thoroughly</a></li> + + <li><a href="#s8">Comment at the end of braces if the content + is more than one screen length</a></li> + </ul> + + <h3><a href="#s9">Naming Conventions</a></h3> + + <ul> + <li><a href="#s10">Variable Names</a></li> + + <li><a href="#s11">Function Names</a></li> + + <li><a href="#s12">Header file prototypes</a></li> + + <li><a href="#s13">Enumerations, and #defines</a></li> + + <li><a href="#s14">Constants</a></li> + </ul> + + <h3><a href="#s15">Using Space</a></h3> + + <ul> + <li><a href="#s16">Put braces on a line by + themselves.</a></li> + + <li><a href="#s17">ALL control statements should have a + block</a></li> + + <li><a href="#s18">Do not belabor/blow-up boolean + expressions</a></li> + + <li><a href="#s19">Use white space freely because it is + free</a></li> + + <li><a href="#s20">Don't use white space around structure + operators</a></li> + + <li><a href="#s21">Make the last brace of a function stand + out</a></li> + + <li><a href="#s22">Use 3 character indentions</a></li> + </ul> + + <h3><a href="#s23">Initializing</a></h3> + + <ul> + <li><a href="#s24">Initialize all variables</a></li> + </ul> + + <h3><a href="#s25">Functions</a></h3> + + <ul> + <li><a href="#s26">Name functions that return a boolean as a + question.</a></li> + + <li><a href="#s27">Always specify a return type for a + function.</a></li> + + <li><a href="#s28">Minimize function calls when iterating by + using variables</a></li> + + <li><a href="#s29">Pass and Return by Const + Reference</a></li> + + <li><a href="#s30">Pass and Return by Value</a></li> + + <li><a href="#s31">Use #include <fileName> and #include + "fileName" for locals</a></li> + + <li><a href="#s32">Provide multiple inclusion + protection</a></li> + + <li><a href="#s33">Use `extern "C"` when appropriate</a></li> + + <li><a href="#s34">Where Possible, Use Forward Struct + Declaration Instead of Includes</a></li> + </ul> + + <h3><a href="#s35">General Coding Practices</a></h3> + + <ul> + <li><a href="#s36">Turn on warnings</a></li> + + <li><a href="#s37">Provide a default case for all switch + statements</a></li> + + <li><a href="#s38">Try to avoid falling through cases in a + switch statement.</a></li> + + <li><a href="#s39">Use 'long' or 'short' Instead of + 'int'</a></li> + + <li><a href="#s40">Don't mix size_t and other types</a></li> + + <li><a href="#s41">Declare each variable and struct on its + own line.</a></li> + + <li><a href="#s42">Use malloc/zalloc sparingly</a></li> + + <li><a href="#s43">The Programmer Who Uses 'malloc' is + Responsible for Ensuring 'free'</a></li> + + <li><a href="#s44">Add loaders to the `file_list' structure + and in order</a></li> + + <li><a href="#s45">"Uncertain" new code and/or changes to + exitinst code, use FIXME</a></li> + </ul> + + <h3><a href="#s46">Addendum: Template for files and function + comment blocks:</a></h3> + + <p> </p> + + <p> </p> + + <h1><a name="s1"></a>Introduction</h1> + + <p>This set of standards is designed to make our lives easier. + It is developed with the simple goal of helping us keep the + "new and improved Junkbusters" consistent and reliable. Thus + making maintenance easier and increasing chances of success of + the project.</p> + + <p>And that of course comes back to us as individuals. If we + can increase our development and product efficiencies then we + can solve more of the request for changes/improvements and in + general feel good about ourselves. ;-></p> + + <p> </p> + + <p> </p> + + <h1><a name="s2"></a>Using Comments</h1> + + <p> </p> + + <h2><a name="s3"></a>Comment, Comment, Comment</h2> + + <p><b>Explanation:</b></p> + + <p>Comment as much as possible without commenting the obvious. + For example do not comment "aVariable is equal to bVariable". + Instead explain why aVariable should be equal to the bVariable. + Just because a person can read code does not mean they will + understand why or what is being done. A reader may spend a lot + more time figuring out what is going on when a simple comment + or explanation would have prevented the extra research. Please + help your brother IJB'ers out!</p> + + <p>The comments will also help justify the intent of the code. + If the comment describes something different than what the code + is doing then maybe a programming error is occurring.</p> + + <p><b>Example:</b></p> +<pre> +/* if page size greater than 1k ... */ +if ( PageLength() > 1024 ) +{ + ... "block" the page up ... +} + +/* if page size is small, send it in blocks */ +if ( PageLength() > 1024 ) +{ + ... "block" the page up ... +} + +This demonstrates 2 cases of "what not to do". The first is a +"syntax comment". The second is a comment that does not fit what +is actually being done. + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s4"></a>Use blocks for comments</h2> + + <p><b>Explanation:</b></p> + + <p>Comments can help or they can clutter. They help when they + are differentiated from the code they describe. One line + comments do not offer effective separation between the comment + and the code. Block identifiers do, by surrounding the code + with a clear, definable pattern.</p> + + <p><b>Example:</b></p> +<pre> +/********************************************************************* + * This will stand out clearly in your code! + *********************************************************************/ +if ( thisVariable == thatVariable ) +{ + DoSomethingVeryImportant(); +} + + +/* unfortunately, this may not */ +if ( thisVariable == thatVariable ) +{ + DoSomethingVeryImportant(); +} + + +if ( thisVariable == thatVariable ) /* this may not either */ +{ + DoSomethingVeryImportant(); +} + +</pre> + + <p><b>Exception:</b></p> + + <p>If you are trying to add a small logic comment and do not + wish to "disrubt" the flow of the code, feel free to use a 1 + line comment which is NOT on the same line as the code.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s5"></a>Keep Comments on their own line</h2> + + <p><b>Explanation:</b></p> + + <p>It goes back to the question of readability. If the comment + is on the same line as the code it will be harder to read than + the comment that is on its own line.</p> + + <p>There are three exceptions to this rule, which should be + violated freely and often: during the definition of variables, + at the end of closing braces, when used to comment + parameters.</p> + + <p><b>Example:</b></p> +<pre> +/********************************************************************* + * This will stand out clearly in your code, + * But the second example won't. + *********************************************************************/ +if ( thisVariable == thatVariable ) +{ + DoSomethingVeryImportant(); +} + +if ( thisVariable == thatVariable ) /*can you see me?*/ +{ + DoSomethingVeryImportant(); /*not easily*/ +} + + +/********************************************************************* + * But, the encouraged exceptions: + *********************************************************************/ +int urls_read = 0; /* # of urls read + rejected */ +int urls_rejected = 0; /* # of urls rejected */ + +if ( 1 == X ) +{ + DoSomethingVeryImportant(); +} + + +short DoSomethingVeryImportant( + short firstParam, /* represents something */ + short nextParam /* represents something else */ ) +{ + ...code here... + +} /* -END- DoSomethingVeryImportant */ + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s6"></a>Comment each logical step</h2> + + <p><b>Explanation:</b></p> + + <p>Logical steps should be commented to help others follow the + intent of the written code and comments will make the code more + readable.</p> + + <p>If you have 25 lines of code without a comment, you should + probably go back into it to see where you forgot to put + one.</p> + + <p>Most "for", "while", "do", etc... loops _probably_ need a + comment. After all, these are usually major logic + containers.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s7"></a>Comment All Functions Thoroughly</h2> + + <p><b>Explanation:</b></p> + + <p>A reader of the code should be able to look at the comments + just prior to the beginning of a function and discern the + reason for its existence and the consequences of using it. The + reader should not have to read through the code to determine if + a given function is safe for a desired use. The proper + information thoroughly presented at the introduction of a + function not only saves time for subsequent maintenance or + debugging, it more importantly aids in code reuse by allowing a + user to determine the safety and applicability of any function + for the problem at hand. As a result of such benefits, all + functions should contain the information presented in the + addendum section of this document.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s8"></a>Comment at the end of braces if the + content is more than one screen length</h2> + + <p><b>Explanation:</b></p> + + <p>Each closing brace should be followed on the same line by a + comment that describes the origination of the brace if the + original brace is off of the screen, or otherwise far away from + the closing brace. This will simplify the debugging, + maintenance, and readability of the code.</p> + + <p>As a suggestion , use the following flags to make the + comment and its brace more readable:</p> + + <p>use following a closing brace: } /* -END- if() or while () + or etc... */</p> + + <p><b>Example:</b></p> +<pre> +if ( 1 == X ) +{ + DoSomethingVeryImportant(); + ...some long list of commands... +} /* -END- if x is 1 */ + +or: + +if ( 1 == X ) +{ + DoSomethingVeryImportant(); + ...some long list of commands... +} /* -END- if ( 1 == X ) */ + + +</pre> + + <p> </p> + + <p> </p> + + <h1><a name="s9"></a>Naming Conventions</h1> + + <p> </p> + + <h2><a name="s10"></a>Variable Names</h2> + + <p><b>Explanation:</b></p> + + <p>Use all lowercase, and seperate words via an underscore + ('_'). Do not start an identifier with an underscore. (ANSI C + reserves these for use by the compiler and system headers.) Do + not use identifiers which are reserved in ANSI C++. (E.g. + template, class, true, false, ...). This is in case we ever + decide to port JunkBuster to C++.</p> + + <p><b>Example:</b></p> +<pre> +int ms_iis5_hack = 0; + +</pre> + + <p><b>Instead of:</b></p> + + <p>int msiis5hack = 0; int msIis5Hack = 0;</p> + + <p> </p> + + <p> </p> + + <h2><a name="s11"></a>Function Names</h2> + + <p><b>Explanation:</b></p> + + <p>Use all lowercase, and seperate words via an underscore + ('_'). Do not start an identifier with an underscore. (ANSI C + reserves these for use by the compiler and system headers.) Do + not use identifiers which are reserved in ANSI C++. (E.g. + template, class, true, false, ...). This is in case we ever + decide to port JunkBuster to C++.</p> + + <p><b>Example:</b></p> +<pre> +int load_some_file( struct client_state *csp ) + +</pre> + + <p><b>Instead of:</b></p> + + <p>int loadsomefile( struct client_state *csp ) int + loadSomeFile( struct client_state *csp )</p> + + <p> </p> + + <p> </p> + + <h2><a name="s12"></a>Header file prototypes</h2> + + <p><b>Explanation:</b></p> + + <p>Use a descriptive parameter name in the function prototype + in header files. Use the same parameter name in the header file + that you use in the c file.</p> + + <p><b>Example:</b></p> +<pre> +(.h) extern int load_aclfile( struct client_state *csp ); +(.c) int load_aclfile( struct client_state *csp ) + +</pre> + + <p><b>Instead of:</b> (.h) extern int load_aclfile( struct + client_state * ); or (.h) extern int load_aclfile(); (.c) int + load_aclfile( struct client_state *csp )</p> + + <p> </p> + + <p> </p> + + <h2><a name="s13"></a>Enumerations, and #defines</h2> + + <p><b>Explanation:</b></p> + + <p>Use all capital letters, with underscores between words. Do + not start an identifier with an underscore. (ANSI C reserves + these for use by the compiler and system headers.)</p> + + <p><b>Example:</b></p> +<pre> +(enumeration) : enum Boolean { FALSE, TRUE }; +(#define) : #define DEFAULT_SIZE 100; + +</pre> + + <p><b>Note:</b> We have a standard naming scheme for #defines + that toggle a feature in the preprocessor: FEATURE_xxx, where + xxx is a short (preferably 1 or 2 word) description.</p> + + <p><b>Example:</b></p> +<pre> +#define FEATURE_FORCE 1 + +#ifdef FEATURE_FORCE +#define FORCE_PREFIX blah +#endif /* def FEATURE_FORCE */ + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s14"></a>Constants</h2> + + <p><b>Explanation:</b></p> + + <p>Spell common words out entirely (do not remove vowels).</p> + + <p>Use only widely-known domain acronyms and abbreviations. + Capitalize all letters of an acronym.</p> + + <p>Use underscore (_) to separate adjacent acronyms and + abbreviations. Never terminate a name with an underscore.</p> + + <p><b>Example:</b></p> +<pre> +#define USE_IMAGE_LIST 1 + +</pre> + + <p><b>Instead of:</b></p> + + <p>#define USE_IMG_LST 1 or #define _USE_IMAGE_LIST 1 or + #define USE_IMAGE_LIST_ 1 or #define use_image_list 1 or + #define UseImageList 1</p> + + <p> </p> + + <p> </p> + + <h1><a name="s15"></a>Using Space</h1> + + <p> </p> + + <h2><a name="s16"></a>Put braces on a line by themselves.</h2> + + <p><b>Explanation:</b></p> + + <p>The brace needs to be on a line all by itself, not at the + end of the statement. Curly braces should line up with the + construct that they're associated with. This practice makes it + easier to identify the opening and closing braces for a + block.</p> + + <p><b>Example:</b></p> +<pre> +if ( this == that ) +{ + ... +} + +</pre> + + <p><b>Instead of:</b></p> + + <p>if ( this == that ) { ... }</p> + + <p>or</p> + + <p>if ( this == that ) { ... }</p> + + <p><b>Note:</b> In the special case that the if-statement is + inside a loop, and it is trivial, i.e. it tests for a + condidtion that is obvious from the purpose of the block, + one-liners as above may optically preserve the loop structure + and make it easier to read.</p> + + <p><b>Status:</b> developer-discrection.</p> + + <p><b>Example exception:</b></p> +<pre> +while ( more lines are read ) +{ + /* Please document what is/is not a comment line here */ + if ( it's a comment ) continue; + + do_something( line ); +} + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s17"></a>ALL control statements should have a + block</h2> + + <p><b>Explanation:</b></p> + + <p>Using braces to make a block will make your code more + readable and less prone to error. All control statements should + have a block defined.</p> + + <p><b>Example:</b></p> +<pre> +if ( this == that ) +{ + DoSomething(); + DoSomethingElse(); +} + +</pre> + + <p><b>Instead of:</b></p> + + <p>if ( this == that ) DoSomething(); DoSomethingElse();</p> + + <p>or</p> + + <p>if ( this == that ) DoSomething();</p> + + <p><b>Note:</b> The first example in "Instead of" will execute + in a manner other than that which the developer desired (per + indentation). Using code braces would have prevented this + "feature". The "explanation" and "exception" from the point + above also applies.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s18"></a>Do not belabor/blow-up boolean + expressions</h2> + + <p><b>Example:</b></p> +<pre> +structure->flag = ( condition ); + +</pre> + + <p><b>Instead of:</b></p> + + <p>if ( condition ) { structure->flag = 1; } else { + structure->flag = 0; }</p> + + <p><b>Note:</b> The former is readable and consice. The later + is wordy and inefficient. Please assume that any developer new + to the project has at least a "good" knowledge of C/C++. (Hope + I do not offend by that last comment ... 8-)</p> + + <p> </p> + + <p> </p> + + <h2><a name="s19"></a>Use white space freely because it is + free</h2> + + <p><b>Explanation:</b></p> + + <p>Make it readable. The notable exception to using white space + freely is listed in the next guideline.</p> + + <p><b>Example:</b></p> +<pre> +int firstValue = 0; +int someValue = 0; +int anotherValue = 0; +int thisVariable = 0; + +if ( thisVariable == thatVariable ) + +firstValue = oldValue + ( ( someValue - anotherValue ) - whatever ) + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s20"></a>Don't use white space around structure + operators</h2> + + <p><b>Explanation:</b></p> + + <p>- structure pointer operator ( "->" ) - member operator ( + "." ) - functions and parentheses</p> + + <p>It is a general coding practice to put pointers, references, + and function parentheses next to names. With spaces, the + connection between the object and variable/function name is not + as clear.</p> + + <p><b>Example:</b></p> +<pre> +aStruct->aMember; +aStruct.aMember; +FunctionName(); + +</pre> + + <p><b>Instead of:</b> aStruct -> aMember; aStruct . aMember; + FunctionName ();</p> + + <p> </p> + + <p> </p> + + <h2><a name="s21"></a>Make the last brace of a function stand + out</h2> + + <p><b>Example:</b></p> +<pre> +int function1( ... ) +{ + ...code... + return( retCode ); + +} /* -END- function1 */ + + +int function2( ... ) +{ +} /* -END- function2 */ + + +</pre> + + <p><b>Instead of:</b></p> + + <p>int function1( ... ) { ...code... return( retCode ); } int + function2( ... ) { }</p> + + <p><b>Note:</b> Use 1 blank line before the closing brace and 2 + lines afterwards. This makes the end of function standout to + the most casual viewer. Although function comments help + seperate functions, this is still a good coding practice. In + fact, I follow these rules when using blocks in "for", "while", + "do" loops, and long if {} statements too. After all whitespace + is free!</p> + + <p><b>Status:</b> developer-discrection on the number of blank + lines. Enforced is the end of function comments.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s22"></a>Use 3 character indentions</h2> + + <p><b>Explanation:</b></p> + + <p>If some use 8 character TABs and some use 3 character TABs, + the code can look *very* ragged. So use 3 character indentions + only. If you like to use TABs, pass your code through a filter + such as "expand -t3" before checking in your code.</p> + + <p><b>Example:</b></p> +<pre> +static const char * const url_code_map[256] = +{ + NULL, ... +}; + + +int function1( ... ) +{ + if ( 1 ) + { + return( ALWAYS_TRUE ); + } + else + { + return( HOW_DID_YOU_GET_HERE ); + } + + return( NEVER_GETS_HERE ); + +} + + +</pre> + + <p> </p> + + <p> </p> + + <h1><a name="s23"></a>Initializing</h1> + + <p> </p> + + <h2><a name="s24"></a>Initialize all variables</h2> + + <p><b>Explanation:</b></p> + + <p>Do not assume that the variables declared will not be used + until after they have been assigned a value somewhere else in + the code. Remove the chance of accidentally using an unassigned + variable.</p> + + <p><b>Example:</b></p> +<pre> +short anShort = 0; +float aFloat = 0; +struct *ptr = NULL; + +</pre> + + <p><b>Note:</b> It is much easier to debug a SIGSEGV if the + message says you are trying to access memory address 00000000 + and not 129FA012; or arrayPtr[20] causes a SIGSEV vs. + arrayPtr[0].</p> + + <p><b>Status:</b> developer-discrection if and only if the + variable is assigned a value "shortly after" declaration.</p> + + <p> </p> + + <p> </p> + + <h1><a name="s25"></a>Functions</h1> + + <p> </p> + + <h2><a name="s26"></a>Name functions that return a boolean as a + question.</h2> + + <p><b>Explanation:</b></p> + + <p>Value should be phrased as a question that would logically + be answered as a true or false statement</p> + + <p><b>Example:</b></p> +<pre> +ShouldWeBlockThis(); +ContainsAnImage(); +IsWebPageBlank(); + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s27"></a>Always specify a return type for a + function.</h2> + + <p><b>Explanation:</b></p> + + <p>The default return for a function is an int. To avoid + ambiguity, create a return for a function when the return has a + purpose, and create a void return type if the function does not + need to return anything.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s28"></a>Minimize function calls when iterating by + using variables</h2> + + <p><b>Explanation:</b></p> + + <p>It is easy to write the following code, and a clear argument + can be made that the code is easy to understand:</p> + + <p><b>Example:</b></p> +<pre> +for ( size_t cnt = 0; cnt < blockListLength(); cnt ++ ) +{ + .... +} + +</pre> + + <p><b>Note:</b> Unfortunately, this makes a function call for + each and every iteration. This increases the overhead in the + program, because the compiler has to look up the function each + time, call it, and return a value. Depending on what occurs in + the blockListLength() call, it might even be creating and + destroying structures with each iteration, even though in each + case it is comparing "cnt" to the same value, over and over. + Remember too - even a call to blockListLength() is a function + call, with the same overhead.</p> + + <p>Instead of using a function call during the iterations, + assign the value to a variable, and evaluate using the + variable.</p> + + <p><b>Example:</b></p> +<pre> +size_t len = blockListLength(); + +for ( size_t cnt = 0; cnt < len; cnt ++ ) +{ + .... +} + +</pre> + + <p><b>Exceptions:</b> if the value of blockListLength() *may* + change or could *potentially* change, then you must code the + function call in the for/while loop.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s29"></a>Pass and Return by Const Reference</h2> + + <p><b>Explanation:</b></p> + + <p>This allows a developer to define a const pointer and call + your function. If your function does not have the const + keyword, we may not be able to use your function. Consider + strcmp, if it were defined as: extern int strcmp( char *s1, + char *s2 );</p> + + <p>I could then not use it to compare argv's in main: int main( + int argc, const char *argv[] ) { strcmp( argv[0], "junkbusters" + ); }</p> + + <p>Both these pointers are *const*! If the c runtime library + maintainers do it, we should too.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s30"></a>Pass and Return by Value</h2> + + <p><b>Explanation:</b></p> + + <p>Most structures cannot fit onto a normal stack entry (i.e. + they are not 4 bytes or less). Aka, a function declaration + like: int load_aclfile( struct client_state csp )</p> + + <p>would not work. So, to be consistent, we should declare all + prototypes with "pass by value": int load_aclfile( struct + client_state *csp )</p> + + <p> </p> + + <p> </p> + + <h2><a name="s31"></a>Use #include <fileName> and + #include "fileName" for locals</h2> + + <p><b>Explanation:</b></p> + + <p>Your include statements should contain the file name without + a path. The path should be listed in the Makefile, using -I as + processor directive to search the indicated paths. An exception + to this would be for some proprietary software that utilizes a + partial path to distinguish their header files from system or + other header files.</p> + + <p><b>Example:</b></p> +<pre> +#include <iostream.h> /* This is not a local include */ +#include "config.h" /* This IS a local include */ + +</pre> + + <p><b>Exception:</b></p> + + <p>/* This is not a local include, but requires a path element. + */ #include <sys/fileName.h></p> + + <p><b>Note:</b> Please! do not add "-I." to the Makefile + without a _very_ good reason. This duplicates the #include + "file.h" behaviour.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s32"></a>Provide multiple inclusion + protection</h2> + + <p><b>Explanation:</b></p> + + <p>Prevents compiler and linker errors resulting from + redefinition of items.</p> + + <p>Wrap each header file with the following syntax to prevent + multiple inclusions of the file. Of course, replace PROJECT_H + with your file name, with "." Changed to "_", and make it + uppercase.</p> + + <p><b>Example:</b></p> +<pre> +#ifndef PROJECT_H_INCLUDED +#define PROJECT_H_INCLUDED + ... +#endif /* ndef PROJECT_H_INCLUDED */ + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s33"></a>Use `extern "C"` when appropriate</h2> + + <p><b>Explanation:</b></p> + + <p>If our headers are included from C++, they must declare our + functions as `extern "C"`. This has no cost in C, but increases + the potential re-usability of our code.</p> + + <p><b>Example:</b></p> +<pre> +#ifdef __cplusplus +extern "C" +{ +#endif /* def __cplusplus */ + +... function definitions here ... + +#ifdef __cplusplus +} +#endif /* def __cplusplus */ + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s34"></a>Where Possible, Use Forward Struct + Declaration Instead of Includes</h2> + + <p><b>Explanation:</b></p> + + <p>Useful in headers that include pointers to other struct's. + Modifications to excess header files may cause needless + compiles.</p> + + <p><b>Example:</b></p> +<pre> +/********************************************************************* + * We're avoiding an include statement here! + *********************************************************************/ +struct file_list; +extern file_list *xyz; + +</pre> + + <p><b>Note:</b> If you declare "file_list xyz;" (without the + pointer), then including the proper header file is necessary. + If you only want to prototype a pointer, however, the header + file is unneccessary.</p> + + <p><b>Status:</b> Use with discrection.</p> + + <p> </p> + + <p> </p> + + <h1><a name="s35"></a>General Coding Practices</h1> + + <p> </p> + + <h2><a name="s36"></a>Turn on warnings</h2> + + <p><b>Explanation</b></p> + + <p>Compiler warnings are meant to help you find bugs. You + should turn on as many as possible. With GCC, the switch is + "-Wall". Try and fix as many warnings as possible.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s37"></a>Provide a default case for all switch + statements</h2> + + <p><b>Explanation:</b></p> + + <p>What you think is guaranteed is never really guaranteed. The + value that you don't think you need to check is the one that + someday will be passed. So, to protect yourself from the + unknown, always have a default step in a switch statement.</p> + + <p><b>Example:</b></p> +<pre> +switch( hash_string( cmd ) ) +{ + case hash_actions_file : + ... code ... + break; + + case hash_confdir : + ... code ... + break; + + default : + log_error( ... ); + ... anomly code goes here ... + continue; / break; / exit( 1 ); / etc ... + +} /* end switch( hash_string( cmd ) ) */ + +</pre> + + <p><b>Note:</b> If you already have a default condition, you + are obviously exempt from this point. Of note, most of the + WIN32 code calls `DefWindowProc' after the switch statement. + This API call *should* be included in a default statement.</p> + + <p><b>Another Note:</b> This is not so much a readability issue + as a robust programming issue. The "anomly code goes here" may + be no more than a print to the STDERR stream (as in + load_config). Or it may really be an ABEND condition.</p> + + <p><b>Status:</b> Programmer discretion is advised.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s38"></a>Try to avoid falling through cases in a + switch statement.</h2> + + <p><b>Explanation:</b></p> + + <p>In general, you will want to have a 'break' statement within + each 'case' of a switch statement. This allows for the code to + be more readable and understandable, and furthermore can + prevent unwanted surprises if someone else later gets creative + and moves the code around.</p> + + <p>The language allows you to plan the fall through from one + case statement to another simply by omitting the break + statement within the case statement. This feature does have + benefits, but should only be used in rare cases. In general, + use a break statement for each case statement.</p> + + <p>If you choose to allow fall through, you should comment both + the fact of the fall through and reason why you felt it was + necessary.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s39"></a>Use 'long' or 'short' Instead of + 'int'</h2> + + <p><b>Explanation:</b></p> + + <p>On 32-bit platforms, int usually has the range of long. On + 16-bit platforms, int has the range of short.</p> + + <p><b>Status:</b> open-to-debate. In the case of most FSF + projects (including X/GNU-Emacs), there are typedefs to int4, + int8, int16, (or equivalence ... I forget the exact typedefs + now). Should we add these to IJB now that we have a "configure" + script?</p> + + <p> </p> + + <p> </p> + + <h2><a name="s40"></a>Don't mix size_t and other types</h2> + + <p><b>Explanation:</b></p> + + <p>The type of size_t varies across platforms. Do not make + assumptions about whether it is signed or unsigned, or about + how long it is. Do not compare a size_t against another + variable of a different type (or even against a constant) + without casting one of the values. Try to avoid using size_t if + you can.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s41"></a>Declare each variable and struct on its + own line.</h2> + + <p><b>Explanation:</b></p> + + <p>It can be tempting to declare a series of variables all on + one line. Don't.</p> + + <p><b>Example:</b></p> +<pre> +long a = 0; +long b = 0; +long c = 0; + +</pre> + + <p><b>Instead of:</b></p> + + <p>long a, b, c;</p> + + <p><b>Explanation:</b> - there is more room for comments on the + individual variables - easier to add new variables without + messing up the original ones - when searching on a variable to + find its type, there is less clutter to "visually" + eliminate</p> + + <p><b>Exceptions:</b> when you want to declare a bunch of loop + variables or other trivial variables; feel free to declare them + on 1 line. You should, although, provide a good comment on + their functions.</p> + + <p><b>Status:</b> developer-discrection.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s42"></a>Use malloc/zalloc sparingly</h2> + + <p><b>Explanation:</b></p> + + <p>Create a local stuct (on the stack) if the variable will + live and die within the context of one function call.</p> + + <p>Only "malloc" a struct (on the heap) if the variable's life + will extend beyond the context of one function call.</p> + + <p><b>Example:</b></p> +<pre> +If a function creates a struct and stores a pointer to it in a +list, then it should definately be allocated via `malloc'. + + +</pre> + + <p> </p> + + <p> </p> + + <h2><a name="s43"></a>The Programmer Who Uses 'malloc' is + Responsible for Ensuring 'free'</h2> + + <p><b>Explanation:</b></p> + + <p>If you have to "malloc" an instance, you are responsible for + insuring that the instance is `free'd, even if the deallocation + event falls within some other programmer's code. You are also + responsible for ensuring that deletion is timely (i.e. not too + soon, not too late). This is known as "low-coupling" and is a + "good thing (tm)". You may need to offer a + free/unload/destuctor type function to accomodate this.</p> + + <p><b>Example:</b></p> +<pre> +int load_re_filterfile( struct client_state *csp ) { ... } +static void unload_re_filterfile( void *f ) { ... } + +</pre> + + <p><b>Exceptions:</b></p> + + <p>The developer cannot be expected to provide `free'ing + functions for C run-time library functions ... such as + `strdup'.</p> + + <p><b>Status:</b> developer-discrection. The "main" use of this + standard is for allocating and freeing data structures (complex + or nested).</p> + + <p> </p> + + <p> </p> + + <h2><a name="s44"></a>Add loaders to the `file_list' structure + and in order</h2> + + <p><b>Explanation:</b></p> + + <p>I have ordered all of the "blocker" file code to be in alpha + order. It is easier to add/read new blockers when you expect a + certain order.</p> + + <p><b>Note:</b> It may appear that the alpha order is broken in + places by POPUP tests coming before PCRS tests. But since + POPUPs can also be referred to as KILLPOPUPs, it is clear that + it should come first.</p> + + <p> </p> + + <p> </p> + + <h2><a name="s45"></a>"Uncertain" new code and/or changes to + exitinst code, use FIXME</h2> + + <p><b>Explanation:</b></p> + + <p>If you have enough confidence in new code or confidence in + your changes, but are not *quite* sure of the reprocussions, + add this:</p> + + <p>/* FIXME: this code has a logic error on platform XYZ, * + attempthing to fix */ #ifdef PLATFORM ...changed code here... + #endif</p> + + <p>or:</p> + + <p>/* FIXME: I think the original author really meant this... + */ ...changed code here...</p> + + <p>or:</p> + + <p>/* FIXME: new code that *may* break something else... */ + ...new code here...</p> + + <p><b>Note:</b> If you make it clear that this may or may not + be a "good thing (tm)", it will be easier to identify and + include in the project (or conversly exclude from the + project).</p> + + <p> </p> + + <p> </p> + + <h1><a name="s46"></a>Addendum: Template for files and function + comment blocks:</h1> + + <p><b>Example for file comments:</b></p> +<pre> +const char FILENAME_rcs[] = "$Id: STANDARDS.txt,v 1.5 2001/09/10 18:37:48 jongfoster Exp $"; +/********************************************************************* + * + * File : $S<!-- Break CVS Substitution -->ource$ + * + * Purpose : (Fill me in with a good description!) + * + * Copyright : Written by and Copyright (C) 2001 the SourceForge + * IJBSWA team. http://ijbswa.sourceforge.net + * + * Based on the Internet Junkbuster originally written + * by and Copyright (C) 1997 Anonymous Coders and + * Junkbusters Corporation. http://www.junkbusters.com + * + * This program is free software; you can redistribute it + * and/or modify it under the terms of the GNU General + * Public License as published by the Free Software + * Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will + * be useful, but WITHOUT ANY WARRANTY; without even the + * implied warranty of MERCHANTABILITY or FITNESS FOR A + * PARTICULAR PURPOSE. See the GNU General Public + * License for more details. + * + * The GNU General Public License should be included with + * this file. If not, you can view it at + * http://www.gnu.org/copyleft/gpl.html + * or write to the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Revisions : + * $L<!-- Break CVS Substitution -->og$ + * + *********************************************************************/ + + +#include "config.h" + + ...necessary include files for us to do our work... + +const char FILENAME_h_rcs[] = FILENAME_H_VERSION; + + +</pre> + + <p><b>Note:</b> This declares the rcs variables that should be + added to the "show-proxy-args" page. If this is a brand new + creation by you, you are free to change the "Copyright" section + to represent the rights you wish to maintain.</p> + + <p><b>Note:</b> The formfeed character that is present right + after the comment flower box is handy for (X|GNU)Emacs users to + skip the verbige and get to the heart of the code (via + `forward-page' and `backward-page'). Please include it if you + can.</p> + + <p><b>Example for file header comments:</b></p> +<pre> +#ifndef _FILENAME_H +#define _FILENAME_H +#define FILENAME_H_VERSION "$Id: STANDARDS.txt,v 1.5 2001/09/10 18:37:48 jongfoster Exp $" +/********************************************************************* + * + * File : $S<!-- Break CVS Substitution -->ource$ + * + * Purpose : (Fill me in with a good description!) + * + * Copyright : Written by and Copyright (C) 2001 the SourceForge + * IJBSWA team. http://ijbswa.sourceforge.net + * + * Based on the Internet Junkbuster originally written + * by and Copyright (C) 1997 Anonymous Coders and + * Junkbusters Corporation. http://www.junkbusters.com + * + * This program is free software; you can redistribute it + * and/or modify it under the terms of the GNU General + * Public License as published by the Free Software + * Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will + * be useful, but WITHOUT ANY WARRANTY; without even the + * implied warranty of MERCHANTABILITY or FITNESS FOR A + * PARTICULAR PURPOSE. See the GNU General Public + * License for more details. + * + * The GNU General Public License should be included with + * this file. If not, you can view it at + * http://www.gnu.org/copyleft/gpl.html + * or write to the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Revisions : + * $L<!-- Break CVS Substitution -->og$ + * + *********************************************************************/ + + +#include "project.h" + +#ifdef __cplusplus +extern "C" { +#endif + + ... function headers here ... + + +/* Revision control strings from this header and associated .c file */ +extern const char FILENAME_rcs[]; +extern const char FILENAME_h_rcs[]; + + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* ndef _FILENAME_H */ + +/* + Local Variables: + tab-width: 3 + end: +*/ + + +</pre> + + <p><b>Example for function comments:</b></p> +<pre> +/********************************************************************* + * + * Function : FUNCTION_NAME + * + * Description : (Fill me in with a good description!) + * + * Parameters : + * 1 : param1 = pointer to an important thing + * 2 : x = pointer to something else + * + * Returns : 0 => Ok, everything else is an error. + * + *********************************************************************/ +int FUNCTION_NAME( void *param1, const char *x ) +{ + ... + return( 0 ); + +} + + +</pre> + + <p><b>Note:</b> If we all follow this practice, we should be + able to parse our code to create a "self-documenting" web + page.</p> + + <p> </p> + + <p> </p> + </body> +</html> + -- 2.49.0