Improved version extraction from clang_getClangVersion()

src/compile_commands.cpp

@@ -84,21 +84,23 @@ std::vector<std::string> CompileCommands::get_arguments(const boost::filesystem:
     }
   }
 
-  static auto resource_path = []() -> std::string {
+  static std::string resource_path = []() -> std::string {
     // Try based on clang_getClangVersion first, even though its format is not guaranteed to be stable.
     auto clang_version = clangmm::to_string(clang_getClangVersion());
-    std::string version;
-    for(auto it = clang_version.rbegin(); it != clang_version.rend() && ((*it >= '0' && *it <= '9') || *it == '.'); ++it)
-      version.insert(version.begin(), *it);
-    while(!version.empty() && version.front() != '.' && version.back() != '.') {
-      auto path = boost::filesystem::path(LIBCLANG_LIBRARY_DIR) / "clang" / version;
-      boost::system::error_code ec;
-      if(boost::filesystem::is_directory(path / "include", ec))
-        return path.string();
-      auto pos = version.rfind('.');
-      if(pos == std::string::npos)
-        break;
-      version.erase(pos);
+    std::regex clang_version_regex("([0-9]+\\.[0-9]+\\.[0-9]+)");
+    std::smatch sm;
+    if(std::regex_search(clang_version, sm, clang_version_regex)) {
+      auto version = sm[1].str();
+      while(!version.empty() && version.front() != '.' && version.back() != '.') {
+        auto path = boost::filesystem::path(LIBCLANG_LIBRARY_DIR) / "clang" / version;
+        boost::system::error_code ec;
+        if(boost::filesystem::is_directory(path / "include", ec))
+          return path.string();
+        auto pos = version.rfind('.');
+        if(pos == std::string::npos)
+          break;
+        version.erase(pos);
+      }
     }
 
     boost::system::error_code ec;