VS10: Load projects with obj "source" files (#11147)

WriteCLSources should skip source files with "obj" extensions
since WriteObjSources has already written them into the vcxproj
file. Likewise, WriteGroupSources should skip source files with
"obj" extensions to avoid receiving "item ... already exists under
the filter" project-load-time error messages from Visual Studio.

Source/cmVisualStudio10TargetGenerator.cxx

@@ -597,7 +597,11 @@ WriteGroupSources(const char* name,
   for(std::vector<cmSourceFile*>::const_iterator s = sources.begin();
       s != sources.end(); ++s)
     {
-    cmSourceFile* sf = *s; 
+    cmSourceFile* sf = *s;
+    if(sf->GetExtension() == "obj")
+      {
+      continue;
+      }
     std::string const& source = sf->GetFullPath();
     cmSourceGroup& sourceGroup = 
       this->Makefile->FindSourceGroup(source.c_str(), sourceGroups);
@@ -666,55 +670,56 @@ void cmVisualStudio10TargetGenerator::WriteCLSources()
   for(std::vector<cmSourceFile*>::const_iterator source = sources.begin();
       source != sources.end(); ++source)
     {
-    // if it is not a custom command then add it as a c/c++ file,
-    // TODO: need to check for idl or rc
-    if(!(*source)->GetCustomCommand())
+    std::string ext = (*source)->GetExtension();
+    if((*source)->GetCustomCommand() || ext == "obj")
       {
-      bool header = (*source)->GetPropertyAsBool("HEADER_FILE_ONLY")
-        || this->GlobalGenerator->IgnoreFile
-        ((*source)->GetExtension().c_str());
-      const char* lang = (*source)->GetLanguage();
-      bool cl = lang && (strcmp(lang, "C") == 0 || strcmp(lang, "CXX") ==0);
-      bool rc = lang && (strcmp(lang, "RC") == 0);
-      bool idl = (*source)->GetExtension() == "idl";
-      std::string sourceFile = (*source)->GetFullPath();
-      sourceFile =  cmSystemTools::RelativePath(
-        this->Makefile->GetCurrentOutputDirectory(),
-        sourceFile.c_str());
-      this->ConvertToWindowsSlash(sourceFile);
-      // output the source file
-      if(header)
-        {
-        this->WriteString("<ClInclude Include=\"", 2);
-        }
-      else if(cl)
-        {
-        this->WriteString("<ClCompile Include=\"", 2);
-        }
-      else if(rc)
-        {
-        this->WriteString("<ResourceCompile Include=\"", 2);
-        }
-      else if(idl)
-        {
-        this->WriteString("<Midl Include=\"", 2);
-        }
-      else
-        {
-        this->WriteString("<None Include=\"", 2);
-        }
-      (*this->BuildFileStream ) << sourceFile << "\"";
-      // ouput any flags specific to this source file
-      if(!header && cl && this->OutputSourceSpecificFlags(*source))
-        {
-        // if the source file has specific flags the tag
-        // is ended on a new line
-        this->WriteString("</ClCompile>\n", 2);
-        }
-      else
-        {
-        (*this->BuildFileStream ) << " />\n";
-        }
+      continue;
+      }
+    // If it is not a custom command and it is not a pre-built obj file,
+    // then add it as a source (c/c++/header/rc/idl) file
+    bool header = (*source)->GetPropertyAsBool("HEADER_FILE_ONLY")
+      || this->GlobalGenerator->IgnoreFile(ext.c_str());
+    const char* lang = (*source)->GetLanguage();
+    bool cl = lang && (strcmp(lang, "C") == 0 || strcmp(lang, "CXX") ==0);
+    bool rc = lang && (strcmp(lang, "RC") == 0);
+    bool idl = ext == "idl";
+    std::string sourceFile = (*source)->GetFullPath();
+    sourceFile =  cmSystemTools::RelativePath(
+      this->Makefile->GetCurrentOutputDirectory(),
+      sourceFile.c_str());
+    this->ConvertToWindowsSlash(sourceFile);
+    // output the source file
+    if(header)
+      {
+      this->WriteString("<ClInclude Include=\"", 2);
+      }
+    else if(cl)
+      {
+      this->WriteString("<ClCompile Include=\"", 2);
+      }
+    else if(rc)
+      {
+      this->WriteString("<ResourceCompile Include=\"", 2);
+      }
+    else if(idl)
+      {
+      this->WriteString("<Midl Include=\"", 2);
+      }
+    else
+      {
+      this->WriteString("<None Include=\"", 2);
+      }
+    (*this->BuildFileStream ) << sourceFile << "\"";
+    // ouput any flags specific to this source file
+    if(!header && cl && this->OutputSourceSpecificFlags(*source))
+      {
+      // if the source file has specific flags the tag
+      // is ended on a new line
+      this->WriteString("</ClCompile>\n", 2);
+      }
+    else
+      {
+      (*this->BuildFileStream ) << " />\n";
       }
     }
   this->WriteString("</ItemGroup>\n", 1);