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
- Privoxy" 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. ;->
4.2. Using Comments
4.2.1. 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.
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
+ Privoxy" 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. ;->
Comment as much as possible without commenting the obvious. For
+ example do not comment "variable_a is equal to variable_b". Instead
+ explain why variable_a should be equal to the variable_b. 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 fellow Privoxy
+ developers 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 (page_length() > 1024)
{
... "block" the page up ...
}
/* if page size is small, send it in blocks */
-if ( PageLength() > 1024 )
+if (page_length() > 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.
4.2.2. 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:
/*********************************************************************
+is actually being done.
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 )
+if (this_variable == that_variable)
{
- DoSomethingVeryImportant();
+ do_something_very_important();
}
/* unfortunately, this may not */
-if ( thisVariable == thatVariable )
+if (this_variable == that_variable)
{
- DoSomethingVeryImportant();
+ do_something_very_important();
}
-if ( thisVariable == thatVariable ) /* this may not either */
+if (this_variable == that_variable) /* this may not either */
{
- DoSomethingVeryImportant();
-}
Exception:
If you are trying to add a small logic comment and do not
- wish to "disrupt" the flow of the code, feel free to use a 1
- line comment which is NOT on the same line as the code.
4.2.3. 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.
If you are trying to add a small logic comment and do not wish to
+ "disrupt" the flow of the code, feel free to use a 1 line comment
+ which is NOT on the same line as the code.
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 )
+if (this_variable == this_variable)
{
- DoSomethingVeryImportant();
+ do_something_very_important();
}
-if ( thisVariable == thatVariable ) /*can you see me?*/
+if (this_variable == this_variable) /*can you see me?*/
{
- DoSomethingVeryImportant(); /*not easily*/
+ do_something_very_important(); /*not easily*/
}
@@ -307,954 +168,445 @@ if ( thisVariable == thatVariable ) /*can you see me?*/
int urls_read = 0; /* # of urls read + rejected */
int urls_rejected = 0; /* # of urls rejected */
-if ( 1 == X )
+if (1 == X)
{
- DoSomethingVeryImportant();
+ do_something_very_important();
}
-short DoSomethingVeryImportant(
+short do_something_very_important(
short firstparam, /* represents something */
short nextparam /* represents something else */ )
{
...code here...
-} /* -END- DoSomethingVeryImportant */
4.2.4. 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.
4.2.5. 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.
4.2.6. 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 )
+} /* -END- do_something_very_important */
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.
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();
+ do_something_very_important();
...some long list of commands...
} /* -END- if x is 1 */
or:
-if ( 1 == X )
+if (1 == X)
{
- DoSomethingVeryImportant();
+ do_something_very_important();
...some long list of commands...
-} /* -END- if ( 1 == X ) */
4.3. Naming Conventions
4.3.1. Variable Names
Explanation:
Use all lowercase, and separate 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 Privoxy to C++.
Example:
int ms_iis5_hack = 0;
Instead of:
int msiis5hack = 0; int msIis5Hack = 0;
4.3.2. Function Names
Explanation:
Use all lowercase, and separate 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 Privoxy to C++.
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 )
4.3.4. 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.)
Note: We have a standard naming scheme for #defines
- that toggle a feature in the preprocessor: FEATURE_>, where
- > is a short (preferably 1 or 2 word) description.
Use all lowercase, and separate 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 Privoxy to C++.
Use all lowercase, and separate 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 Privoxy 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)
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)
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.)
Note: We
+ have a standard naming scheme for #defines that toggle a feature in
+ the preprocessor: FEATURE_>, where > is a short (preferably 1
+ or 2 word) description.
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 use_image_list 1 or
-#define UseImageList 1
4.4. Using Space
4.4.1. 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.
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
- condition 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-discretion.
Example exception:
while ( more lines are read )
+}
+
+
+
+
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 condition 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-discretion.
+
Example
+ exception:
+
+
+
+
while (more lines are read)
{
/* Please document what is/is not a comment line here */
- if ( it's a comment ) continue;
+ if (it's a comment) continue;
- do_something( line );
-}
4.4.2. 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.
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.
4.4.3. Do not belabor/blow-up boolean
- expressions
Note: The former is readable and concise. 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-)
4.4.4. 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.
4.4.5. 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.
4.4.6. Make the last brace of a function stand
- out
Example:
int function1( ... )
+ do_something();
+ do_something_else();
+}
+
+
+
+
Instead
+ of:
+
if (this == that) do_something(); do_something_else();
+
or
+
if (this == that) do_something();
+
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.
Note: The
+ former is readable and concise. 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-)
- 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.
int function1( ... ) { ...code... return( retCode ); } int
- function2( ... ) { }
Note: Use 1 blank line before the closing brace and 2
- lines afterward. This makes the end of function standout to
- the most casual viewer. Although function comments help
- separate 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-discretion on the number of blank
- lines. Enforced is the end of function comments.
4.4.7. 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.
int function1( ... ) { ...code... return(ret_code); } int
+ function2( ... ) { }
+
Note: Use 1
+ blank line before the closing brace and 2 lines afterward. This makes
+ the end of function standout to the most casual viewer. Although
+ function comments help separate 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-discretion on the number of blank lines. Enforced is the
+ end of function comments.
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.
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.
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-discretion if and only if the
- variable is assigned a value "shortly after" declaration.
4.6. Functions
4.6.1. 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
4.6.2. 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.
4.6.3. 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:
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.
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 array_ptr[20]
+ causes a SIGSEV vs. array_ptr[0].
+
Status:
+ developer-discretion if and only if the variable is assigned a value
+ "shortly after" declaration.
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.
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();
+}
+
+
+
+
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 block_list_length() 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 block_list_length() 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.
Exceptions: if the value of blockListLength() *may*
- change or could *potentially* change, then you must code the
- function call in the for/while loop.
4.6.4. 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], "privoxy"
- ); }
Both these pointers are *const*! If the c runtime library
- maintainers do it, we should too.
4.6.5. 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 )
4.6.6. Names of include files
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" behavior.
4.6.7. 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
+}
+
+
+
+
Exceptions:
+ if the value of block_list_length() *may* change or could
+ *potentially* change, then you must code the function call in the
+ for/while loop.
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], "privoxy"); }
+
Both these pointers are *const*! If the c runtime library
+ maintainers do it, we should too.
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)
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" behavior.
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.
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.
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.
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 unnecessary.
Status: Use with discretion.
4.7. General Coding Practices
4.7.1. 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.
4.7.2. 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.
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 unnecessary.
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.
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 :
+ case hash_actions_file:
... code ...
break;
- case hash_confdir :
+ case hash_confdir:
... code ...
break;
- default :
+ default:
log_error( ... );
... anomaly 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 "anomaly 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.
4.7.3. 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.
4.7.4. 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?
4.7.5. 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.
4.7.6. 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;
+} /* 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 "anomaly code goes here" may be no more than a
+ print to the STDERR stream (as in load_config). Or it may really be
+ an abort condition.
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.
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.
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-discretion.
4.7.7. Use malloc/zalloc sparingly
Explanation:
Create a local struct (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 definitely be allocated via `malloc'.
4.7.8. 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/destructor type function to accommodate this.
The developer cannot be expected to provide `free'ing
- functions for C run-time library functions ... such as
- `strdup'.
Status: developer-discretion. The "main" use of this
- standard is for allocating and freeing data structures (complex
- or nested).
4.7.9. 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.
4.7.10. "Uncertain" new code and/or changes to
- existing code, use FIXME
Explanation:
If you have enough confidence in new code or confidence in
- your changes, but are not *quite* sure of the repercussions,
- add this:
/* FIXME: this code has a logic error on platform XYZ, *
- attempting 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 conversely exclude from the
- project).
4.8. Addendum: Template for files and function
- comment blocks:
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 one line. You should,
+ although, provide a good comment on their functions.
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/destructor type function to
+ accommodate this.
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.
If you have enough confidence in new code or confidence in your
+ changes, but are not *quite* sure of the repercussions, add this:
+
/* XXX: this code has a logic error on platform XYZ, * attempting
+ to fix */ #ifdef PLATFORM ...changed code here... #endif
+
or:
+
/* XXX: I think the original author really meant this... */
+ ...changed code here...
+
or:
+
/* XXX: 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 conversely
+ exclude from the project).
+ const char FILENAME_rcs[] = "$I<!-- Break CVS Substitution -->d$";
/*********************************************************************
*
- * File : $Source$
+ * File : $S<!-- Break CVS Substitution -->ource$
*
* Purpose : (Fill me in with a good description!)
*
- * Copyright : Written by and Copyright (C) 2001 the SourceForge
- * Privoxy team. http://www.privoxy.org/
- *
- * Based on the Internet Junkbuster originally written
- * by and Copyright (C) 1997 Anonymous Coders and
- * Junkbusters Corporation. http://www.junkbusters.com
+ * Copyright : Written by and Copyright (C) 2001-2009
+ * the Privoxy team. https://www.privoxy.org/
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
@@ -2362,12 +1112,10 @@ CLASS="PROGRAMLISTING"
*
* 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 :
- * $Log$
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 ,
+ * USA
*
*********************************************************************/
@@ -2376,64 +1124,36 @@ CLASS="PROGRAMLISTING"
...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 verbiage and get to the heart of the code (via
- `forward-page' and `backward-page'). Please include it if you
- can.
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 verbiage 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: developer-manual.sgml,v 2.7 2006/07/18 14:48:50 david__schmidt Exp $"
+#define FILENAME_H_VERSION "$I<!-- Break CVS Substitution -->d$"
/*********************************************************************
*
- * File : $Source$
+ * File : $S<!-- Break CVS Substitution -->ource$
*
* Purpose : (Fill me in with a good description!)
*
- * Copyright : Written by and Copyright (C) 2001 the SourceForge
- * Privoxy team. http://www.privoxy.org/
- *
- * Based on the Internet Junkbuster originally written
- * by and Copyright (C) 1997 Anonymous Coders and
- * Junkbusters Corporation. http://www.junkbusters.com
+ * Copyright : Written by and Copyright (C) 2001-2009
+ * the Privoxy team. https://www.privoxy.org/
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
@@ -2449,12 +1169,10 @@ CLASS="PROGRAMLISTING"
*
* 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 :
- * $Log$
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 ,
+ * USA
*
*********************************************************************/
@@ -2483,27 +1201,17 @@ extern const char FILENAME_h_rcs[];
Local Variables:
tab-width: 3
end:
-*/