GN threading refactor

tools/gn/builder.h

Index: tools/gn/builder.h
diff --git a/tools/gn/builder.h b/tools/gn/builder.h
new file mode 100644
index 0000000000000000000000000000000000000000..aea4baf1d1579ee78913ba97fc86ecc20cc0bfe3
--- /dev/null
+++ b/tools/gn/builder.h
@@ -0,0 +1,135 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TOOLS_GN_BUILDER_H_
+#define TOOLS_GN_BUILDER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/containers/hash_tables.h"
+#include "base/memory/ref_counted.h"
+#include "tools/gn/builder_record.h"
+#include "tools/gn/label.h"
+#include "tools/gn/label_ptr.h"
+
+class Config;
+class Err;
+class Loader;
+class ParseNode;
+
+class Builder : public base::RefCountedThreadSafe<Builder> {
+ public:
+  typedef base::Callback<void(const Item*)> ResolvedCallback;
+
+  Builder(Loader* loader);
+
+  // The resolved callback is called whenever a target has been resolved. This
+  // will be executed only on the main thread.
+  void set_resolved_callback(const ResolvedCallback& cb) {
+    resolved_callback_ = cb;
+  }
+
+  Loader* loader() const { return loader_; }
+
+  void ItemDefined(scoped_ptr<Item> item);
+
+  // Returns NULL if there is not a thing with the corresponding label.
+  const Item* GetItem(const Label& label) const;
+  const Toolchain* GetToolchain(const Label& label) const;
+
+  std::vector<const BuilderRecord*> GetAllRecords() const;
+
+  // Returns targets which should be generated and which are defined.
+  std::vector<const Target*> GetAllResolvedTargets() const;
+
+  // Returns the record for the given label, or NULL if it doesn't exist.
+  // Mostly used for unit tests.
+  const BuilderRecord* GetRecord(const Label& label) const;
+  BuilderRecord* GetRecord(const Label& label);
+
+  // If there are any undefined references, returns false and sets the error.
+  bool CheckForBadItems(Err* err) const;
+
+ private:
+  friend class base::RefCountedThreadSafe<Builder>;
+
+  virtual ~Builder();
+
+  bool TargetDefined(BuilderRecord* record, Err* err);
+
+  // Returns the record associated with the given label. This function checks
+  // that if we already have references for it, the type matches. If no record
+  // exists yet, a new one will be created.
+  //
+  // If any of the conditions fail, the return value will be null and the error
+  // will be set. request_from is used as the source of the error.
+  BuilderRecord* GetOrCreateRecordOfType(const Label& label,
+                                         const ParseNode* request_from,
+                                         BuilderRecord::ItemType type,
+                                         Err* err);
+
+  // Returns the record associated with the given label. This function checks
+  // that it's already been resolved to the correct type.
+  //
+  // If any of the conditions fail, the return value will be null and the error
+  // will be set. request_from is used as the source of the error.
+  BuilderRecord* GetResolvedRecordOfType(const Label& label,
+                                         const ParseNode* request_from,
+                                         BuilderRecord::ItemType type,
+                                         Err* err);
+
+  bool AddDeps(BuilderRecord* record,
+               const LabelConfigVector& configs,
+               Err* err);
+  bool AddDeps(BuilderRecord* record,
+               const LabelTargetVector& targets,
+               Err* err);
+  bool AddToolchainDep(BuilderRecord* record,
+                       const Target* target,
+                       Err* err);
+
+  // Given a target, sets the "should generate" bit and pushes it through the
+  // dependency tree. Any time the bit it set, we ensure that the given item is
+  // scheduled to be loaded.
+  //
+  // If the force flag is set, we'll ignore the current state of the record's
+  // should_generate flag, and set it on the dependents every time. This is
+  // used when defining a target: the "should generate" may have been set
+  // before the item was defined (if it is required by something that is
+  // required). In this case, we need to re-push the "should generate" flag
+  // to the item's dependencies.
+  void RecursiveSetShouldGenerate(BuilderRecord* record, bool force);
+
+  void ScheduleItemLoadIfNecessary(BuilderRecord* record);
+
+  // This takes a BuilderRecord with resolved depdencies, and fills in the
+  // target's Label*Vectors with the resolved pointers.
+  bool ResolveItem(BuilderRecord* record, Err* err);
+
+  // Fills in the pointers in the given vector based on the labels. We assume
+  // that everything should be resolved by this point, so will return an error
+  // if anything isn't found or if the type doesn't match.
+  bool ResolveDeps(LabelTargetVector* deps, Err* err);
+  bool ResolveConfigs(LabelConfigVector* configs, Err* err);
+  bool ResolveForwardDependentConfigs(Target* target, Err* err);
+
+  // Given a list of unresolved records, tries to find any circular
+  // dependencies and returns the string describing the problem. If no circular
+  // deps were found, returns the empty string.
+  std::string CheckForCircularDependencies(
+      const std::vector<const BuilderRecord*>& bad_records) const;
+
+  // Non owning pointer.
+  Loader* loader_;
+
+  // Owning pointers.
+  typedef base::hash_map<Label, BuilderRecord*> RecordMap;
+  RecordMap records_;
+
+  ResolvedCallback resolved_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(Builder);
+};
+
+#endif  // TOOLS_GN_BUILDER_H_