4d066836e3
This uses the previously added scripts to convert the documentation to reStructuredText, which is both easier to read offline, and can be used to generate modern HTML for online documentation. No modification to the generated results have been done. Acked-by: Eric Engestrom <eric@engestrom.ch> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4630>
125 lines
4.0 KiB
ReStructuredText
125 lines
4.0 KiB
ReStructuredText
Coding Style
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============
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Mesa is over 20 years old and the coding style has evolved over time.
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Some old parts use a style that's a bit out of date. Different sections
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of mesa can use different coding style as set in the local EditorConfig
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(.editorconfig) and/or Emacs (.dir-locals.el) file. Alternatively the
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following is applicable. If the guidelines below don't cover something,
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try following the format of existing, neighboring code.
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Basic formatting guidelines
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- 3-space indentation, no tabs.
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- Limit lines to 78 or fewer characters. The idea is to prevent line
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wrapping in 80-column editors and terminals. There are exceptions,
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such as if you're defining a large, static table of information.
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- Opening braces go on the same line as the if/for/while statement. For
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example:
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::
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if (condition) {
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foo;
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} else {
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bar;
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}
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- Put a space before/after operators. For example, ``a = b + c;`` and
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not ``a=b+c;``
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- This GNU indent command generally does the right thing for
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formatting:
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::
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indent -br -i3 -npcs --no-tabs infile.c -o outfile.c
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- Use comments wherever you think it would be helpful for other
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developers. Several specific cases and style examples follow. Note
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that we roughly follow `Doxygen <http://www.doxygen.nl>`__
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conventions.
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Single-line comments:
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::
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/* null-out pointer to prevent dangling reference below */
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bufferObj = NULL;
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Or,
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::
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bufferObj = NULL; /* prevent dangling reference below */
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Multi-line comment:
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::
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/* If this is a new buffer object id, or one which was generated but
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* never used before, allocate a buffer object now.
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*/
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We try to quote the OpenGL specification where prudent:
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::
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/* Page 38 of the PDF of the OpenGL ES 3.0 spec says:
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*
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* "An INVALID_OPERATION error is generated for any of the following
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* conditions:
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*
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* * <length> is zero."
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*
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* Additionally, page 94 of the PDF of the OpenGL 4.5 core spec
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* (30.10.2014) also says this, so it's no longer allowed for desktop GL,
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* either.
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*/
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Function comment example:
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::
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/**
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* Create and initialize a new buffer object. Called via the
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* ctx->Driver.CreateObject() driver callback function.
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* \param name integer name of the object
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* \param type one of GL_FOO, GL_BAR, etc.
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* \return pointer to new object or NULL if error
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*/
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struct gl_object *
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_mesa_create_object(GLuint name, GLenum type)
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{
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/* function body */
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}
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- Put the function return type and qualifiers on one line and the
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function name and parameters on the next, as seen above. This makes
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it easy to use ``grep ^function_name dir/*`` to find function
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definitions. Also, the opening brace goes on the next line by itself
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(see above.)
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- Function names follow various conventions depending on the type of
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function:
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::
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glFooBar() - a public GL entry point (in glapi_dispatch.c)
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_mesa_FooBar() - the internal immediate mode function
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save_FooBar() - retained mode (display list) function in dlist.c
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foo_bar() - a static (private) function
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_mesa_foo_bar() - an internal non-static Mesa function
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- Constants, macros and enum names are ``ALL_UPPERCASE``, with \_
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between words.
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- Mesa usually uses camel case for local variables (Ex:
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``localVarname``) while gallium typically uses underscores (Ex:
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``local_var_name``).
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- Global variables are almost never used because Mesa should be
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thread-safe.
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- Booleans. Places that are not directly visible to the GL API should
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prefer the use of ``bool``, ``true``, and ``false`` over
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``GLboolean``, ``GL_TRUE``, and ``GL_FALSE``. In C code, this may
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mean that ``#include <stdbool.h>`` needs to be added. The
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``try_emit_*`` methods in ``src/mesa/program/ir_to_mesa.cpp`` and
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``src/mesa/state_tracker/st_glsl_to_tgsi.cpp`` can serve as examples.
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