AutoRcc: Rebuild if the rcc executable is newer than its output

In AUTORCC add a test if the rcc executable is newer that the rcc output.
If the rcc executable is newer, rebuild the output.

Source/cmQtAutoRcc.cxx

@@ -75,6 +75,13 @@ bool cmQtAutoRcc::Init(cmMakefile* makefile)
 
   // - Rcc executable
   RccExecutable_ = InfoGet("ARCC_RCC_EXECUTABLE");
+  if (!RccExecutableTime_.Load(RccExecutable_)) {
+    std::string error = "The rcc executable ";
+    error += Quoted(RccExecutable_);
+    error += " does not exist.";
+    Log().ErrorFile(GenT::RCC, InfoFile(), error);
+    return false;
+  }
   RccListOptions_ = InfoGetList("ARCC_RCC_LIST_OPTIONS");
 
   // - Job
@@ -336,6 +343,18 @@ bool cmQtAutoRcc::TestQrcRccFiles(bool& generate)
     return true;
   }
 
+  // Test if the rcc output file is older than the rcc executable
+  if (RccFileTime_.Older(RccExecutableTime_)) {
+    if (Log().Verbose()) {
+      Reason = "Generating ";
+      Reason += Quoted(RccFileOutput_);
+      Reason += ", because it is older than the rcc executable, from ";
+      Reason += Quoted(QrcFile_);
+    }
+    generate = true;
+    return true;
+  }
+
   return true;
 }
 

Source/cmQtAutoRcc.h

@@ -54,6 +54,7 @@ private:
   std::string IncludeDir_;
   // -- Qt environment
   std::string RccExecutable_;
+  cmFileTime RccExecutableTime_;
   std::vector<std::string> RccListOptions_;
   // -- Job
   std::string LockFile_;