GN threading refactor

tools/gn/build_settings.h

Index: tools/gn/build_settings.h
diff --git a/tools/gn/build_settings.h b/tools/gn/build_settings.h
index fc175dfe795167204e97b678c664a4b9df8bb93a..2e93296bc237375c39ded91cadfeee4e689e2c5e 100644
--- a/tools/gn/build_settings.h
+++ b/tools/gn/build_settings.h
@@ -10,21 +10,20 @@
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
+#include "base/memory/scoped_ptr.h"
 #include "tools/gn/args.h"
-#include "tools/gn/item_tree.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/source_dir.h"
 #include "tools/gn/source_file.h"
-#include "tools/gn/target_manager.h"
-#include "tools/gn/toolchain_manager.h"
 
+class Item;
 class OutputFile;
 
 // Settings for one build, which is one toplevel output directory. There
 // may be multiple Settings objects that refer to this, one for each toolchain.
 class BuildSettings {
  public:
-  typedef base::Callback<void(const Target*)> TargetResolvedCallback;
+  typedef base::Callback<void(scoped_ptr<Item>)> ItemDefinedCallback;
 
   BuildSettings();
   BuildSettings(const BuildSettings& other);
@@ -44,13 +43,6 @@ class BuildSettings {
   }
   void SetSecondarySourcePath(const SourceDir& d);
 
-  // Set when we're running an external generator (e.g. GYP) and should
-  // enable "external" flags on targets.
-  bool using_external_generator() const { return using_external_generator_; }
-  void set_using_external_generator(bool ueg) {
-    using_external_generator_ = ueg;
-  }
-
   // Path of the python executable to run scripts with.
   base::FilePath python_path() const { return python_path_; }
   void set_python_path(const base::FilePath& p) { python_path_ = p; }
@@ -74,16 +66,6 @@ class BuildSettings {
   Args& build_args() { return build_args_; }
   const Args& build_args() const { return build_args_; }
 
-  // These accessors do not return const objects since the resulting objects
-  // are threadsafe. In this setting, we use constness primarily to ensure
-  // that the Settings object is used in a threadsafe manner. Although this
-  // violates the concept of logical constness, that's less important in our
-  // application, and actually implementing this in a way that preserves
-  // logical constness is cumbersome.
-  ItemTree& item_tree() const { return item_tree_; }
-  TargetManager& target_manager() const { return target_manager_; }
-  ToolchainManager& toolchain_manager() const { return toolchain_manager_; }
-
   // Returns the full absolute OS path cooresponding to the given file in the
   // root source tree.
   base::FilePath GetFullPath(const SourceFile& file) const;
@@ -95,22 +77,16 @@ class BuildSettings {
   base::FilePath GetFullPathSecondary(const SourceFile& file) const;
   base::FilePath GetFullPathSecondary(const SourceDir& dir) const;
 
-  // This is the callback to execute when a target is marked resolved. If we
-  // don't need to do anything, this will be null. When a target is resolved,
-  // this callback should be posted to the scheduler pool so the work is
-  // distributed properly.
-  const TargetResolvedCallback& target_resolved_callback() const {
-    return target_resolved_callback_;
-  }
-  void set_target_resolved_callback(const TargetResolvedCallback& cb) {
-    target_resolved_callback_ = cb;
+  // Called when an item is defined from a background thread.
+  void ItemDefined(scoped_ptr<Item> item) const;
+  void set_item_defined_callback(ItemDefinedCallback cb) {
+    item_defined_callback_ = cb;
   }
 
  private:
   base::FilePath root_path_;
   std::string root_path_utf8_;
   base::FilePath secondary_source_path_;
-  bool using_external_generator_;
   base::FilePath python_path_;
 
   SourceFile build_config_file_;
@@ -118,12 +94,7 @@ class BuildSettings {
   std::string build_to_source_dir_string_;
   Args build_args_;
 
-  TargetResolvedCallback target_resolved_callback_;
-
-  // See getters above.
-  mutable ItemTree item_tree_;
-  mutable TargetManager target_manager_;
-  mutable ToolchainManager toolchain_manager_;
+  ItemDefinedCallback item_defined_callback_;
 
   BuildSettings& operator=(const BuildSettings& other);  // Disallow.
 };