Autogen: Process files concurrently in AUTOMOC and AUTOUIC

This introduces concurrent thread processing in the `_autogen`
target wich processes AUTOMOC and AUTOUIC.
Source file parsing is distributed among the threads by
using a job queue from which the threads pull new parse jobs.
Each thread might start an independent ``moc`` or ``uic`` process.
Altogether this roughly speeds up the AUTOMOC and AUTOUIC build
process by the number of physical CPUs on the host system.

The exact number of threads to start in  the `_autogen` target
is controlled by the new AUTOGEN_PARALLEL target property which
is initialized by the new CMAKE_AUTOGEN_PARALLEL variable.
If AUTOGEN_PARALLEL is empty or unset (which is the default)
the thread count is set to the number of physical CPUs on
the host system.

The AUTOMOC/AUTOUIC generator and the AUTORCC generator are
refactored to use a libuv loop internally.

Closes #17422.

1 files changed, 8 insertions, 3 deletions

diff --git a/Source/cmQtAutoGeneratorInitializer.h b/Source/cmQtAutoGeneratorInitializer.h
index e06e1c4..0567437 100644
--- a/Source/cmQtAutoGeneratorInitializer.h
+++ b/Source/cmQtAutoGeneratorInitializer.h
@@ -13,7 +13,8 @@
 
 class cmGeneratorTarget;
 
-class cmQtAutoGeneratorInitializer
+/// @brief Initializes the QtAutoGen generators
+class cmQtAutoGeneratorInitializer : public cmQtAutoGen
 {
 public:
   static std::string GetQtMajorVersion(cmGeneratorTarget const* target);
@@ -55,11 +56,15 @@ private:
   void SetupCustomTargetsUic();
 
   std::vector<std::string> AddGeneratedSource(std::string const& filename,
-                                              cmQtAutoGen::Generator genType);
+                                              GeneratorT genType);
 
   bool QtVersionGreaterOrEqual(unsigned long requestMajor,
                                unsigned long requestMinor) const;
 
+  bool RccListInputs(std::string const& fileName,
+                     std::vector<std::string>& files,
+                     std::string& errorMessage);
+
 private:
   cmGeneratorTarget* Target;
   bool MocEnabled;
@@ -73,7 +78,7 @@ private:
   // Configurations
   std::string ConfigDefault;
   std::vector<std::string> ConfigsList;
-  cmQtAutoGen::MultiConfig MultiConfig;
+  MultiConfigT MultiConfig;
   // Names
   std::string AutogenTargetName;
   std::string AutogenFolder;