Performance: Improve efficiency of source file lookup in cmMakefile

This reintroduces the change from commit v3.10.0-rc1~69^2 (Performance:
Improve efficiency of source file lookup in cmMakefile, 2017-08-17) with
some corrections.  The original was rolled back by commit
v3.10.0-rc1~52^2~1 (Revert "Performance: ...", 2017-09-25) due to
incompatibilities found.  The rollback was followed-up by addition of a
test for the offending case, and this revision passes the test.

1 files changed, 25 insertions, 0 deletions

diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index fde77a70a1..2a5bb6c9ef 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -200,6 +200,11 @@ cmake::cmake(Role role)
   this->SourceFileExtensions.push_back("M");
   this->SourceFileExtensions.push_back("mm");
 
+  std::copy(this->SourceFileExtensions.begin(),
+            this->SourceFileExtensions.end(),
+            std::inserter(this->SourceFileExtensionsSet,
+                          this->SourceFileExtensionsSet.end()));
+
   this->HeaderFileExtensions.push_back("h");
   this->HeaderFileExtensions.push_back("hh");
   this->HeaderFileExtensions.push_back("h++");
@@ -208,6 +213,11 @@ cmake::cmake(Role role)
   this->HeaderFileExtensions.push_back("hxx");
   this->HeaderFileExtensions.push_back("in");
   this->HeaderFileExtensions.push_back("txx");
+
+  std::copy(this->HeaderFileExtensions.begin(),
+            this->HeaderFileExtensions.end(),
+            std::inserter(this->HeaderFileExtensionsSet,
+                          this->HeaderFileExtensionsSet.end()));
 }
 
 cmake::~cmake()
@@ -1647,6 +1657,21 @@ void cmake::AddCacheEntry(const std::string& key, const char* value,
   this->UnwatchUnusedCli(key);
 }
 
+std::string cmake::StripExtension(const std::string& file) const
+{
+  auto dotpos = file.rfind('.');
+  if (dotpos != std::string::npos) {
+    auto ext = file.substr(dotpos + 1);
+#if defined(_WIN32) || defined(__APPLE__)
+    ext = cmSystemTools::LowerCase(ext);
+#endif
+    if (this->IsSourceExtension(ext) || this->IsHeaderExtension(ext)) {
+      return file.substr(0, dotpos);
+    }
+  }
+  return file;
+}
+
 const char* cmake::GetCacheDefinition(const std::string& name) const
 {
   return this->State->GetInitializedCacheValue(name);