Mercurial > hgrepos > Python2 > PyMuPDF
diff mupdf-source/thirdparty/curl/docs/CODE_STYLE.md @ 2:b50eed0cc0ef upstream
ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4.
The directory name has changed: no version number in the expanded directory now.
| author | Franz Glasner <fzglas.hg@dom66.de> |
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| date | Mon, 15 Sep 2025 11:43:07 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mupdf-source/thirdparty/curl/docs/CODE_STYLE.md Mon Sep 15 11:43:07 2025 +0200 @@ -0,0 +1,246 @@ +# curl C code style + +Source code that has a common style is easier to read than code that uses +different styles in different places. It helps making the code feel like one +single code base. Easy-to-read is a very important property of code and helps +making it easier to review when new things are added and it helps debugging +code when developers are trying to figure out why things go wrong. A unified +style is more important than individual contributors having their own personal +tastes satisfied. + +Our C code has a few style rules. Most of them are verified and upheld by the +`lib/checksrc.pl` script. Invoked with `make checksrc` or even by default by +the build system when built after `./configure --enable-debug` has been used. + +It is normally not a problem for anyone to follow the guidelines, as you just +need to copy the style already used in the source code and there are no +particularly unusual rules in our set of rules. + +We also work hard on writing code that are warning-free on all the major +platforms and in general on as many platforms as possible. Code that obviously +will cause warnings will not be accepted as-is. + +## Naming + +Try using a non-confusing naming scheme for your new functions and variable +names. It doesn't necessarily have to mean that you should use the same as in +other places of the code, just that the names should be logical, +understandable and be named according to what they're used for. File-local +functions should be made static. We like lower case names. + +See the [INTERNALS](INTERNALS.md) document on how we name non-exported +library-global symbols. + +## Indenting + +We use only spaces for indentation, never TABs. We use two spaces for each new +open brace. + + if(something_is_true) { + while(second_statement == fine) { + moo(); + } + } + +## Comments + +Since we write C89 code, **//** comments are not allowed. They weren't +introduced in the C standard until C99. We use only **/* comments */**. + + /* this is a comment */ + +## Long lines + +Source code in curl may never be wider than 79 columns and there are two +reasons for maintaining this even in the modern era of very large and high +resolution screens: + +1. Narrower columns are easier to read than very wide ones. There's a reason + newspapers have used columns for decades or centuries. + +2. Narrower columns allow developers to easier show multiple pieces of code + next to each other in different windows. I often have two or three source + code windows next to each other on the same screen - as well as multiple + terminal and debugging windows. + +## Braces + +In if/while/do/for expressions, we write the open brace on the same line as +the keyword and we then set the closing brace on the same indentation level as +the initial keyword. Like this: + + if(age < 40) { + /* clearly a youngster */ + } + +You may omit the braces if they would contain only a one-line statement: + + if(!x) + continue; + +For functions the opening brace should be on a separate line: + + int main(int argc, char **argv) + { + return 1; + } + +## 'else' on the following line + +When adding an **else** clause to a conditional expression using braces, we +add it on a new line after the closing brace. Like this: + + if(age < 40) { + /* clearly a youngster */ + } + else { + /* probably grumpy */ + } + +## No space before parentheses + +When writing expressions using if/while/do/for, there shall be no space +between the keyword and the open parenthesis. Like this: + + while(1) { + /* loop forever */ + } + +## Use boolean conditions + +Rather than test a conditional value such as a bool against TRUE or FALSE, a +pointer against NULL or != NULL and an int against zero or not zero in +if/while conditions we prefer: + + result = do_something(); + if(!result) { + /* something went wrong */ + return result; + } + +## No assignments in conditions + +To increase readability and reduce complexity of conditionals, we avoid +assigning variables within if/while conditions. We frown upon this style: + + if((ptr = malloc(100)) == NULL) + return NULL; + +and instead we encourage the above version to be spelled out more clearly: + + ptr = malloc(100); + if(!ptr) + return NULL; + +## New block on a new line + +We never write multiple statements on the same source line, even for very +short if() conditions. + + if(a) + return TRUE; + else if(b) + return FALSE; + +and NEVER: + + if(a) return TRUE; + else if(b) return FALSE; + +## Space around operators + +Please use spaces on both sides of operators in C expressions. Postfix **(), +[], ->, ., ++, --** and Unary **+, - !, ~, &** operators excluded they should +have no space. + +Examples: + + bla = func(); + who = name[0]; + age += 1; + true = !false; + size += -2 + 3 * (a + b); + ptr->member = a++; + struct.field = b--; + ptr = &address; + contents = *pointer; + complement = ~bits; + empty = (!*string) ? TRUE : FALSE; + +## No parentheses for return values + +We use the 'return' statement without extra parentheses around the value: + + int works(void) + { + return TRUE; + } + +## Parentheses for sizeof arguments + +When using the sizeof operator in code, we prefer it to be written with +parentheses around its argument: + + int size = sizeof(int); + +## Column alignment + +Some statements cannot be completed on a single line because the line would be +too long, the statement too hard to read, or due to other style guidelines +above. In such a case the statement will span multiple lines. + +If a continuation line is part of an expression or sub-expression then you +should align on the appropriate column so that it's easy to tell what part of +the statement it is. Operators should not start continuation lines. In other +cases follow the 2-space indent guideline. Here are some examples from +libcurl: + + if(Curl_pipeline_wanted(handle->multi, CURLPIPE_HTTP1) && + (handle->set.httpversion != CURL_HTTP_VERSION_1_0) && + (handle->set.httpreq == HTTPREQ_GET || + handle->set.httpreq == HTTPREQ_HEAD)) + /* didn't ask for HTTP/1.0 and a GET or HEAD */ + return TRUE; + +If no parenthesis, use the default indent: + + data->set.http_disable_hostname_check_before_authentication = + (0 != va_arg(param, long)) ? TRUE : FALSE; + +Function invoke with an open parenthesis: + + if(option) { + result = parse_login_details(option, strlen(option), + (userp ? &user : NULL), + (passwdp ? &passwd : NULL), + NULL); + } + +Align with the "current open" parenthesis: + + DEBUGF(infof(data, "Curl_pp_readresp_ %d bytes of trailing " + "server response left\n", + (int)clipamount)); + +## Platform dependent code + +Use **#ifdef HAVE_FEATURE** to do conditional code. We avoid checking for +particular operating systems or hardware in the #ifdef lines. The HAVE_FEATURE +shall be generated by the configure script for unix-like systems and they are +hard-coded in the `config-[system].h` files for the others. + +We also encourage use of macros/functions that possibly are empty or defined +to constants when libcurl is built without that feature, to make the code +seamless. Like this example where the **magic()** function works differently +depending on a build-time conditional: + + #ifdef HAVE_MAGIC + void magic(int a) + { + return a + 2; + } + #else + #define magic(x) 1 + #endif + + int content = magic(3);
