Autogen: Refactor AUTOMOC and AUTOUIC and add source file parse data caching

New features
------------

CMake's `AUTOMOC` and `AUTOUIC` now cache information extracted when parsing
source files in `CMakeFiles/<ORIGIN>_autogen.dir/ParseCache.txt`.
This leads to faster `<ORIGIN>_autogen` target rebuilds, because source files
will be parsed again only if they're newer than the `ParseCache.txt` file.
The parse cache will be recomputed if it is older than the CMake executable.

`AUTOMOC` and `AUTOUIC` now check if `moc` or `uic` output files are older
than the `moc` or `uic` executable.  If an output file is older than the
compiler, it will be regenerated.  Therefore if a new `moc` or `uic` version
is installed, all output files will be regenerated.

`AUTOMOC` and `AUTOUIC` error and warning messages are more detailed.

Internal changes
----------------

`moc` and `uic` output file names are not computed in the `_autogen`
target anymore but in `cmQtAutoGenInitializer`.  This makes the available at
the configuration stage for improved dependency computations (to be done).

In `AutogenInfo.cmake`, equally sized lists for "source file names",
"source file flags" and "compiler output file names" are passed to the
`_autogen` target.  This replaces the separate file lists for
`AUTOMOC` and `AUTOUIC`.

Files times are read from the file system only once by using `cmFileTime`
instances instead of `cmQtAutoGenerator::FileSystem::FileIsOlderThan` calls.

All calls to not thread safe file system functions are moved to non concurrent
fence jobs (see `cmWorkerPool::JobT::IsFence()`).  This renders the
`cmQtAutoGenerator::FileSystem` wrapper class obsolete and it is removed.

Instead of composing a single large settings string that is fed to the
`cmCryptoHash`, now all setting sub strings are fed one by one to the
`cmCryptoHash` and the finalized result is stored.

The `std::mutex` in `cmQtAutoGenerator::Logger` is tagged `mutable` and most
`cmQtAutoGenerator::Logger` methods become `const`.

Outlook
-------

This patch provides the framework required to

- extract dependencies from `.ui` files in `AUTOUIC`.
  These will help to address issue
  #15420 "AUTOUIC: Track uic external inputs".

- generate adaptive `make` and `ninja` files in the `_autogen` target.
  These will help to address issue
  #16776 "AUTOUIC: Ninja needs two passes to correctly build Qt project".

- generate (possibly empty) `moc` and `uic` files for all headers instead of a
  `mocs_compilation.cpp` file.
  This will help to address issue
  #17277 "AUTOMOC: Provide a option to allow AUTOMOC to compile individual "
         "moc_x.cxx instead of including all in mocs_compilation.cxx"

1 files changed, 19 insertions, 75 deletions

diff --git a/Source/cmQtAutoGenerator.h b/Source/cmQtAutoGenerator.h
index 437fa20..ff4c4c9 100644
--- a/Source/cmQtAutoGenerator.h
+++ b/Source/cmQtAutoGenerator.h
@@ -5,7 +5,7 @@
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
-#include "cmFilePathChecksum.h"
+#include "cmFileTime.h"
 #include "cmQtAutoGen.h"
 
 #include <mutex>
@@ -14,13 +14,17 @@
 
 class cmMakefile;
 
-/// @brief Base class for QtAutoGen gernerators
+/** \class cmQtAutoGenerator
+ * \brief Base class for QtAutoGen generators
+ */
 class cmQtAutoGenerator : public cmQtAutoGen
 {
 public:
   // -- Types
 
-  /// @brief Thread safe logging
+  /**
+   * Thread safe logger
+   */
   class Logger
   {
   public:
@@ -37,24 +41,24 @@ public:
     bool ColorOutput() const { return this->ColorOutput_; }
     void SetColorOutput(bool value);
     // -- Log info
-    void Info(GenT genType, std::string const& message);
+    void Info(GenT genType, std::string const& message) const;
     // -- Log warning
-    void Warning(GenT genType, std::string const& message);
+    void Warning(GenT genType, std::string const& message) const;
     void WarningFile(GenT genType, std::string const& filename,
-                     std::string const& message);
+                     std::string const& message) const;
     // -- Log error
-    void Error(GenT genType, std::string const& message);
+    void Error(GenT genType, std::string const& message) const;
     void ErrorFile(GenT genType, std::string const& filename,
-                   std::string const& message);
+                   std::string const& message) const;
     void ErrorCommand(GenT genType, std::string const& message,
                       std::vector<std::string> const& command,
-                      std::string const& output);
+                      std::string const& output) const;
 
   private:
     static std::string HeadLine(std::string const& title);
 
   private:
-    std::mutex Mutex_;
+    mutable std::mutex Mutex_;
     unsigned int Verbosity_ = 0;
     bool ColorOutput_ = false;
   };
@@ -66,70 +70,8 @@ public:
   static bool FileWrite(std::string const& filename,
                         std::string const& content,
                         std::string* error = nullptr);
-
-  /// @brief Thread safe file system interface
-  class FileSystem
-  {
-  public:
-    FileSystem();
-    ~FileSystem();
-
-    // -- Paths
-    /// @brief Wrapper for cmSystemTools::GetRealPath
-    std::string GetRealPath(std::string const& filename);
-    /// @brief Wrapper for cmSystemTools::CollapseFullPath
-    std::string CollapseFullPath(std::string const& file,
-                                 std::string const& dir);
-    /// @brief Wrapper for cmSystemTools::SplitPath
-    void SplitPath(const std::string& p, std::vector<std::string>& components,
-                   bool expand_home_dir = true);
-    /// @brief Wrapper for cmSystemTools::JoinPath
-    std::string JoinPath(const std::vector<std::string>& components);
-    /// @brief Wrapper for cmSystemTools::JoinPath
-    std::string JoinPath(std::vector<std::string>::const_iterator first,
-                         std::vector<std::string>::const_iterator last);
-    /// @brief Wrapper for cmSystemTools::GetFilenameWithoutLastExtension
-    std::string GetFilenameWithoutLastExtension(const std::string& filename);
-    /// @brief Wrapper for cmQtAutoGen::SubDirPrefix
-    std::string SubDirPrefix(std::string const& filename);
-    /// @brief Wrapper for cmFilePathChecksum::setupParentDirs
-    void setupFilePathChecksum(std::string const& currentSrcDir,
-                               std::string const& currentBinDir,
-                               std::string const& projectSrcDir,
-                               std::string const& projectBinDir);
-    /// @brief Wrapper for cmFilePathChecksum::getPart
-    std::string GetFilePathChecksum(std::string const& filename);
-
-    // -- File access
-    /// @brief Wrapper for cmSystemTools::FileExists
-    bool FileExists(std::string const& filename);
-    /// @brief Wrapper for cmSystemTools::FileExists
-    bool FileExists(std::string const& filename, bool isFile);
-    /// @brief Wrapper for cmSystemTools::FileLength
-    unsigned long FileLength(std::string const& filename);
-    bool FileIsOlderThan(std::string const& buildFile,
-                         std::string const& sourceFile,
-                         std::string* error = nullptr);
-
-    bool FileRead(std::string& content, std::string const& filename,
-                  std::string* error = nullptr);
-
-    bool FileWrite(std::string const& filename, std::string const& content,
-                   std::string* error = nullptr);
-
-    bool FileDiffers(std::string const& filename, std::string const& content);
-
-    bool FileRemove(std::string const& filename);
-    bool Touch(std::string const& filename, bool create = false);
-
-    // -- Directory access
-    bool MakeDirectory(std::string const& dirname);
-    bool MakeParentDirectory(std::string const& filename);
-
-  private:
-    std::mutex Mutex_;
-    cmFilePathChecksum FilePathChecksum_;
-  };
+  static bool FileDiffers(std::string const& filename,
+                          std::string const& content);
 
 public:
   // -- Constructors
@@ -142,8 +84,9 @@ public:
   // -- Run
   bool Run(std::string const& infoFile, std::string const& config);
 
-  // InfoFile
+  // -- InfoFile
   std::string const& InfoFile() const { return InfoFile_; }
+  cmFileTime const& InfoFileTime() const { return InfoFileTime_; }
   std::string const& InfoDir() const { return InfoDir_; }
   std::string const& InfoConfig() const { return InfoConfig_; }
 
@@ -158,6 +101,7 @@ protected:
 private:
   // -- Info settings
   std::string InfoFile_;
+  cmFileTime InfoFileTime_;
   std::string InfoDir_;
   std::string InfoConfig_;
 };