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Contributing to SolveSpace
Contributing bug reports
Bug reports are always welcome! When reporting a bug, please include the following:
- The version of SolveSpace (use Help → About...);
- The operating system;
- The save file that reproduces the incorrect behavior, or, if trivial or impossible, instructions for reproducing it.
GitHub does not allow attaching *.slvs
files, but it does allow attaching *.zip
files,
so any savefiles should first be archived.
Contributing translations
To contribute a translation, not a lot is necessary—at a minimum, you need to be able
to edit .po files with a tool such as poedit. Once you have
such a tool installed, take res/messages.pot
and start translating!
However, if you want to see your translation in action, a little more work is necessary. First, you need to be able to build SolveSpace; see README. After that:
- Copy
res/messages.pot
tores/locales/xx_YY.po
, wherexx
is an ISO 639-1 country code, andYY
is an ISO 3166-1 language code. - Add a line
xx-YY,LCID,Name
tores/locales.txt
, wherexx-YY
have the same meaning as above,LCID
is a Windows Language Code Identifier (MS-LCID has a complete list), andName
is the full name of your locale in your language. - Add
locales/xx_YY.po
inres/CMakeLists.txt
—search forlocales/en_US.po
to see where it should be added.
You're done! Recompile SolveSpace and you should be able to select your translation via Help → Language.
Contributing code
SolveSpace is written in C++, and currently targets all compilers compliant with C++11. This includes GCC 5 and later, Clang 3.3 and later, and Visual Studio 12 (2013) and later.
High-level conventions
Portability
SolveSpace aims to consist of two general parts: a fully portable core, and platform-specific
UI and support code. Anything outside of src/platform/
should only use standard C++11,
and rely on src/platform/unixutil.cpp
and src/platform/w32util.cpp
to interact with
the OS where this cannot be done through the C++11 standard library.
Libraries
SolveSpace primarily relies on the C++11 STL. STL has well-known drawbacks, but is also widely supported, used, and understood. SolveSpace also includes a fair amount of use of bespoke containers List and IdList; these provide STL iterators, and can be used when convenient, such as when reusing other code.
One notable departure here is the STL I/O threads. SolveSpace does not use STL I/O threads for two reasons: (i) the interface is borderline unusable, and (ii) on Windows it is not possible to open files with Unicode paths through STL.
When using external libraries (other than to access platform features), the libraries should satisfy the following conditions:
- Portable, and preferably not interacting with the platform at all;
- Can be included as a CMake subproject, to facilitate Windows, Android, etc. builds;
- Use a license less restrictive than GPL (BSD/MIT, Apache2, MPL, etc.)
String encoding
Internally, SolveSpace exclusively stores and uses UTF-8 for all purposes; any std::string
may be assumed to be encoded in UTF-8. On Windows, UTF-8 strings are converted to and from
wide strings at the boundary; see UTF-8 Everywhere for details.
String formatting
For string formatting, a wrapper around sprintf
, ssprintf
, is used. A notable
pitfall when using it is trying to pass an std::string
argument without first converting
it to a C string with .c_str()
.
Filesystem access
For filesystem access, the C standard library is used. The ssfopen
and ssremove
wrappers are provided that accept UTF-8 encoded paths.
Assertions
To ensure that internal invariants hold, the ssassert
function is used, e.g.
ssassert(!isFoo, "Unexpected foo condition");
. Unlike the standard assert
function,
the ssassert
function is always enabled, even in release builds. It is more valuable
to discover a bug through a crash than to silently generate incorrect results, and crashes
do not result in losing more than a few minutes of work thanks to the autosave feature.
Use of C++ features
The conventions described in this section should be used for all new code, but there is a lot of existing code in SolveSpace that does not use them. This is fine; don't touch it if it works, but if you need to modify it anyway, might as well modernize it.
Exceptions
Exceptions are not used primarily because SolveSpace's testsuite uses measurement of branch coverage, important for the critical parts such as the geometric kernel. Every function call with exceptions enabled introduces a branch, making branch coverage measurement useless.
Operator overloading
Operator overloading is not used primarily for historical reasons. Instead, method such
as Plus
are used.
Member visibility
Member visibility is not used for implementation hiding. Every member field and function
is public
.
Constructors
Constructors are not used for initialization, chiefly because indicating an error
in a constructor would require throwing an exception, nor does it use constructors for
blanket zero-initialization because of the performance impact of doing this for common
POD classes like Vector
.
Instances can be zero-initialized using the aggregate-initialization syntax, e.g. Foo foo = {};
.
This zero-initializes the POD members and default-initializes the non-POD members, generally
being an equivalent of memset(&foo, 0, sizeof(foo));
but compatible with STL containers.
Input- and output-arguments
Functions accepting an input argument take it either by-value (Vector v
) or
by-const-reference (const Vector &v
). Generally, passing by-value is safer as the value
cannot be aliased by something else, but passing by-const-reference is faster, as a copy is
eliminated. Small values should always be passed by-value, and otherwise functions that do not
capture pointers into their arguments should take them by-const-reference. Use your judgement.
Functions accepting an output argument always take it by-pointer (Vector *v
). This makes
it immediately visible at the call site as it is seen that the address is taken. Arguments
are never passed by-reference, except when needed for interoperability with STL, etc.
Iteration
foreach
-style iteration is preferred for both STL and List
/IdList
containers as it indicates
intent clearly, as opposed to for
-style.
Const correctness
Functions that do not mutate this
should be marked as const
; when iterating a collection
without mutating any of its elements, for(const Foo &elem : collection)
is preferred to indicate
the intent.
Coding style
Code is formatted by the following rules:
- Code is indented using 4 spaces, with no trailing spaces, and lines are wrapped at 100 columns;
- Braces are placed at the end of the line with the declaration or control flow statement;
- Braces are used with every control flow statement, even if there is only one statement in the body;
- There is no space after control flow keywords (
if
,while
, etc.); - Identifiers are formatted in camel case; variables start with a lowercase letter
(
exampleVariable
) and functions start with an uppercase letter (ExampleFunction
).
For example:
std::string SolveSpace::Dirname(std::string filename) {
int slash = filename.rfind(PATH_SEP);
if(slash >= 0) {
return filename.substr(0, slash);
}
return "";
}
Debugging code
SolveSpace releases are throughly tested but sometimes they contain crash bugs anyway. The reason for such crashes can be determined only if the executable was built with debug information.
Debugging a released version
The Linux distributions usually include separate debug information packages. On a Debian derivative (e.g. Ubuntu), these can be installed with:
apt-get install solvespace-dbg
The macOS releases include the debug information, and no further action is needed.
The Windows releases include the debug information on the GitHub release downloads page.
Debugging a custom build
If you are building SolveSpace yourself on a Unix-like platform, configure or re-configure SolveSpace to produce a debug build, and then re-build it:
cd build
cmake .. -DCMAKE_BUILD_TYPE=Debug [other cmake args...]
make
If you are building SolveSpace yourself using the Visual Studio IDE, select Debug from the Solution Configurations list box on the toolbar, and build the solution.
Debugging with gdb
gdb is a debugger that is mostly used on Linux. First, run SolveSpace under debugging:
gdb [path to solvespace executable]
(gdb) run
Then, reproduce the crash. After the crash, attach the output in the console, as well as output of the following gdb commands to a bug report:
(gdb) backtrace
(gdb) info locals
If the crash is not easy to reproduce, please generate a core file, which you can use to resume the debugging session later, and provide any other information that is requested:
(gdb) generate-core-file
This will generate a large file called like core.1234
in the current
directory; it can be later re-loaded using gdb --core core.1234
.
Debugging with lldb
lldb is a debugger that is mostly used on macOS. First, run SolveSpace under debugging:
lldb [path to solvespace executable]
(lldb) run
Then, reproduce the crash. After the crash, attach the output in the console, as well as output of the following gdb commands to a bug report:
(lldb) backtrace all
(lldb) frame variable
If the crash is not easy to reproduce, please generate a core file, which you can use to resume the debugging session later, and provide any other information that is requested:
(lldb) process save-core "core"
This will generate a large file called core
in the current
directory; it can be later re-loaded using lldb -c core
.
Debugging GUI-related bugs on Linux
There are several environment variables available that make crashes earlier and errors more informative. Before running SolveSpace, run the following commands in your shell:
export G_DEBUG=fatal_warnings
export LIBGL_DEBUG=1
export MESA_DEBUG=1