meson: use vcs_tag for git version information

This way, the command is run every time we change the Wayfire version
and not only when meson reconfigures itself.

meson.build

@@ -4,7 +4,7 @@ project(
 	'cpp',
 	version: '0.9.0',
 	license: 'MIT',
-	meson_version: '>=0.56.0',
+	meson_version: '>=0.63.0',
 	default_options: [
 		'cpp_std=c++17',
 		'c_std=c11',
@@ -13,6 +13,9 @@ project(
 	],
 )
 
+version = '"@0@"'.format(meson.project_version())
+add_project_arguments('-DWAYFIRE_VERSION=@0@'.format(version), language: 'cpp')
+
 wayfire_api_inc  = include_directories('src/api')
 
 wayland_server = dependency('wayland-server')
@@ -83,22 +86,6 @@ backtrace = meson.get_compiler('cpp').find_library('execinfo', required: false)
 
 conf_data = configuration_data()
 
-version = '"@0@"'.format(meson.project_version())
-git = find_program('git', native: true, required: false)
-if git.found()
-	git_commit = run_command([git, 'rev-parse', '--short', 'HEAD'], check: false)
-	git_branch = run_command([git, 'rev-parse', '--abbrev-ref', 'HEAD'], check: false)
-	if git_commit.returncode() == 0 and git_branch.returncode() == 0
-		version = '"@0@-@1@ (" __DATE__ ", branch \'@2@\')"'.format(
-			meson.project_version(),
-			git_commit.stdout().strip(),
-			git_branch.stdout().strip(),
-		)
-	endif
-endif
-add_project_arguments('-DWAYFIRE_VERSION=@0@'.format(version), language: 'cpp')
-conf_data.set('WAYFIRE_VERSION', '-DWAYFIRE_VERSION=@0@'.format(version))
-
 conf_data.set('INSTALL_PREFIX', get_option('prefix'))
 conf_data.set('PLUGIN_PATH', join_paths(get_option('prefix'), get_option('libdir'), 'wayfire'))
 metadata_dir_suffix = 'share/wayfire/metadata'

src/api/wayfire/debug.hpp

@@ -19,6 +19,16 @@ namespace wf
  */
 void dump_scene(scene::node_ptr root = wf::get_core().scene());
 
+/**
+ * Information about the version that Wayfire was built with.
+ * Made available at runtime.
+ */
+namespace version
+{
+extern std::string git_commit;
+extern std::string git_branch;
+}
+
 namespace log
 {
 /**

src/main.cpp

@@ -3,25 +3,22 @@
 #include <iostream>
 #include <getopt.h>
 #include <signal.h>
-#include <map>
 #include <fcntl.h>
-#include <filesystem>
 
 #include <unistd.h>
 #include <wayfire/debug.hpp>
 #include "main.hpp"
-#include "wayfire/nonstd/safe-list.hpp"
 
 #include <wayland-server.h>
 
 #include "wayfire/config-backend.hpp"
 #include "core/plugin-loader.hpp"
 #include "core/core-impl.hpp"
-#include "wayfire/output.hpp"
 
 static void print_version()
 {
-    std::cout << WAYFIRE_VERSION << std::endl;
+    std::cout << WAYFIRE_VERSION << "-" << wf::version::git_commit <<
+        " (" __DATE__ ") branch " << wf::version::git_branch << std::endl;
     exit(0);
 }
 

src/meson.build

@@ -90,6 +90,22 @@ if print_trace
   debug_arguments += ['-DPRINT_TRACE']
 endif
 
+# Generate information about Wayfire version
+git = find_program('git', native: true, required: false)
+git_commit_info = vcs_tag(
+    input: 'version/git-commit.cpp.in',
+    output: 'git-commit.cpp',
+    replace_string: '@GIT_COMMIT@',
+    command: git.found() ? [git, 'rev-parse', '--short', 'HEAD'] : ['echo', 'unknown'],
+    fallback: 'unknown')
+
+git_branch_info = vcs_tag(
+    input: 'version/git-branch.cpp.in',
+    output: 'git-branch.cpp',
+    replace_string: '@GIT_BRANCH@',
+    command: git.found() ? [git, 'rev-parse', '--abbrev-ref', 'HEAD'] : ['echo', 'unknown'],
+    fallback: 'unknown')
+
 # First build a static library of all sources, so that it can be reused
 # in tests
 libwayfire_sta = static_library('libwayfire', wayfire_sources,
@@ -105,7 +121,7 @@ libwayfire = declare_dependency(link_whole: libwayfire_sta,
 tests_include_dirs = include_directories('.')
 
 # Generate main executable
-executable('wayfire', ['main.cpp'],
+executable('wayfire', ['main.cpp', git_commit_info, git_branch_info],
     dependencies: libwayfire,
     install: true,
     cpp_args: debug_arguments)

src/version/git-branch.cpp.in

@@ -0,0 +1,9 @@
+#include <wayfire/debug.hpp>
+
+namespace wf
+{
+namespace version
+{
+std::string git_branch = "@GIT_BRANCH@";
+}
+}

src/version/git-commit.cpp.in

@@ -0,0 +1,9 @@
+#include <wayfire/debug.hpp>
+
+namespace wf
+{
+namespace version
+{
+std::string git_commit = "@GIT_COMMIT@";
+}
+}