[Refactor Xcode Objects] Enable generating per file '--help' compiler flag

tools/gn/xcode_object.h

Index: tools/gn/xcode_object.h
diff --git a/tools/gn/xcode_object.h b/tools/gn/xcode_object.h
index 2ad43cceefc4567abad8d2ca2123794f0c0cf606..263ce88f1ee1d595d580b5d29bdf638ba5e8eacc 100644
--- a/tools/gn/xcode_object.h
+++ b/tools/gn/xcode_object.h
@@ -153,8 +153,11 @@ class PBXAggregateTarget : public PBXTarget {
 
 class PBXBuildFile : public PBXObject {
  public:
+  enum HelpCompilerFlagEnabled { HELP_FLAG_ENABLED, HELP_FLAG_DISABLED };

[sdefresne, 2016/12/17 00:07:27]

I don't really like the redundancy of the enumeration name and value and
variable.

What about moving the enum outside of the class, renaming it to CompilerFlags,
changing it to enum class (for proper scoping) and renaming the variable as
compiler_flags_.

Something like this:

enum class CompilerFlags {
  NONE,
  HELP,
};

class PBXBuildFile : public PBXObject {
 public:
  PBXBuildFile(const PBXFileReference* file_reference,
               const PBXSourcesBuildPhase* build_phase,
               CompilerFlags compiler_flags);
  ...
};

Then you can use it like this, later in the code:

  if (compiler_flags_ == CompilerFlags::HELP) {
    std::map<std::string, std::string> ...
  }

[liaoyuke, 2016/12/19 08:02:40]

Thank you for explaining the details. This is a much better design and it would
be more flexible if one needs to add other flags.

+
   PBXBuildFile(const PBXFileReference* file_reference,
-               const PBXSourcesBuildPhase* build_phase);
+               const PBXSourcesBuildPhase* build_phase,
+               const HelpCompilerFlagEnabled help_flag_enabled);
   ~PBXBuildFile() override;
 
   // PXBObject implementation.
@@ -165,6 +168,7 @@ class PBXBuildFile : public PBXObject {
  private:
   const PBXFileReference* file_reference_;
   const PBXSourcesBuildPhase* build_phase_;
+  const HelpCompilerFlagEnabled help_flag_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(PBXBuildFile);
 };
@@ -247,7 +251,8 @@ class PBXNativeTarget : public PBXTarget {
                   const PBXFileReference* product_reference);
   ~PBXNativeTarget() override;
 
-  void AddFileForIndexing(const PBXFileReference* file_reference);
+  void AddFileForIndexing(const PBXFileReference* file_reference,
+                          const PBXBuildFile::HelpCompilerFlagEnabled);
 
   // PBXObject implementation.
   PBXObjectClass Class() const override;
@@ -271,7 +276,9 @@ class PBXProject : public PBXObject {
              const PBXAttributes& attributes);
   ~PBXProject() override;
 
-  void AddSourceFile(const std::string& source_path);
+  void AddSourceFile(
+      const std::string& source_path,
+      const PBXBuildFile::HelpCompilerFlagEnabled help_flag_enabled);
   void AddAggregateTarget(const std::string& name,
                           const std::string& shell_script);
   void AddNativeTarget(const std::string& name,