Save source dependencies from custom command trace

In each target we trace dependencies among custom commands to pull in
all source files and build rules necessary to complete the target.  This
commit teaches cmTarget to save the inter-source dependencies found
during its analysis.  Later this can be used by generators that need to
topologically order custom command rules.

Source/cmTarget.cxx

@@ -88,6 +88,10 @@ public:
 
   typedef std::map<cmStdString, cmTarget::LinkClosure> LinkClosureMapType;
   LinkClosureMapType LinkClosureMap;
+
+  struct SourceEntry { std::vector<cmSourceFile*> Depends; };
+  typedef std::map<cmSourceFile*, SourceEntry> SourceEntriesType;
+  SourceEntriesType SourceEntries;
 };
 
 //----------------------------------------------------------------------------
@@ -1081,12 +1085,16 @@ bool cmTarget::IsAppBundleOnApple()
 class cmTargetTraceDependencies
 {
 public:
-  cmTargetTraceDependencies(cmTarget* target, const char* vsProjectFile);
+  cmTargetTraceDependencies(cmTarget* target, cmTargetInternals* internal,
+                            const char* vsProjectFile);
   void Trace();
 private:
   cmTarget* Target;
+  cmTargetInternals* Internal;
   cmMakefile* Makefile;
   cmGlobalGenerator* GlobalGenerator;
+  typedef cmTargetInternals::SourceEntry SourceEntry;
+  SourceEntry* CurrentEntry;
   std::queue<cmSourceFile*> SourceQueue;
   std::set<cmSourceFile*> SourcesQueued;
   typedef std::map<cmStdString, cmSourceFile*> NameMapType;
@@ -1102,13 +1110,15 @@ private:
 
 //----------------------------------------------------------------------------
 cmTargetTraceDependencies
-::cmTargetTraceDependencies(cmTarget* target, const char* vsProjectFile):
+::cmTargetTraceDependencies(cmTarget* target, cmTargetInternals* internal,
-  Target(target)
+                            const char* vsProjectFile):
+  Target(target), Internal(internal)
 {
   // Convenience.
   this->Makefile = this->Target->GetMakefile();
   this->GlobalGenerator =
     this->Makefile->GetLocalGenerator()->GetGlobalGenerator();
+  this->CurrentEntry = 0;
 
   // Queue all the source files already specified for the target.
   std::vector<cmSourceFile*> const& sources = this->Target->GetSourceFiles();
@@ -1140,6 +1150,7 @@ void cmTargetTraceDependencies::Trace()
     // Get the next source from the queue.
     cmSourceFile* sf = this->SourceQueue.front();
     this->SourceQueue.pop();
+    this->CurrentEntry = &this->Internal->SourceEntries[sf];
 
     // Queue dependencies added explicitly by the user.
     if(const char* additionalDeps = sf->GetProperty("OBJECT_DEPENDS"))
@@ -1161,6 +1172,7 @@ void cmTargetTraceDependencies::Trace()
       this->CheckCustomCommand(*cc);
       }
     }
+  this->CurrentEntry = 0;
 }
 
 //----------------------------------------------------------------------------
@@ -1188,6 +1200,12 @@ void cmTargetTraceDependencies::FollowName(std::string const& name)
     }
   if(cmSourceFile* sf = i->second)
     {
+    // Record the dependency we just followed.
+    if(this->CurrentEntry)
+      {
+      this->CurrentEntry->Depends.push_back(sf);
+      }
+
     this->QueueSource(sf);
     }
 }
@@ -1308,7 +1326,7 @@ cmTargetTraceDependencies
 void cmTarget::TraceDependencies(const char* vsProjectFile)
 {
   // Use a helper object to trace the dependencies.
-  cmTargetTraceDependencies tracer(this, vsProjectFile);
+  cmTargetTraceDependencies tracer(this, this->Internal.Get(), vsProjectFile);
   tracer.Trace();
 }
 
@@ -1336,12 +1354,30 @@ std::vector<cmSourceFile*> const& cmTarget::GetSourceFiles()
 //----------------------------------------------------------------------------
 void cmTarget::AddSourceFile(cmSourceFile* sf)
 {
-  if(this->SourceFileSet.insert(sf).second)
+  typedef cmTargetInternals::SourceEntriesType SourceEntriesType;
+  SourceEntriesType::iterator i = this->Internal->SourceEntries.find(sf);
+  if(i == this->Internal->SourceEntries.end())
     {
+    typedef cmTargetInternals::SourceEntry SourceEntry;
+    SourceEntriesType::value_type entry(sf, SourceEntry());
+    i = this->Internal->SourceEntries.insert(entry).first;
     this->SourceFiles.push_back(sf);
     }
 }
 
+//----------------------------------------------------------------------------
+std::vector<cmSourceFile*> const*
+cmTarget::GetSourceDepends(cmSourceFile* sf)
+{
+  typedef cmTargetInternals::SourceEntriesType SourceEntriesType;
+  SourceEntriesType::iterator i = this->Internal->SourceEntries.find(sf);
+  if(i != this->Internal->SourceEntries.end())
+    {
+    return &i->second.Depends;
+    }
+  return 0;
+}
+
 //----------------------------------------------------------------------------
 void cmTarget::AddSources(std::vector<std::string> const& srcs)
 {

Source/cmTarget.h

@@ -48,6 +48,7 @@ public:
   ~cmTargetInternalPointer();
   cmTargetInternalPointer& operator=(cmTargetInternalPointer const& r);
   cmTargetInternals* operator->() const { return this->Pointer; }
+  cmTargetInternals* Get() const { return this->Pointer; }
 private:
   cmTargetInternals* Pointer;
 };
@@ -122,6 +123,9 @@ public:
   std::vector<cmSourceFile*> const& GetSourceFiles();
   void AddSourceFile(cmSourceFile* sf);
 
+  /** Get sources that must be built before the given source.  */
+  std::vector<cmSourceFile*> const* GetSourceDepends(cmSourceFile* sf);
+
   /**
    * Flags for a given source file as used in this target. Typically assigned
    * via SET_TARGET_PROPERTIES when the property is a list of source files.
@@ -530,7 +534,6 @@ private:
   std::vector<cmCustomCommand> PostBuildCommands;
   TargetType TargetTypeValue;
   std::vector<cmSourceFile*> SourceFiles;
-  std::set<cmSourceFile*> SourceFileSet;
   LinkLibraryVectorType LinkLibraries;
   LinkLibraryVectorType PrevLinkedLibraries;
   bool LinkLibrariesAnalyzed;