GN threading refactor

tools/gn/builder_record.h

+// 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_RECORD_H_
+#define TOOLS_GN_BUILDER_RECORD_H_
+
+#include <set>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "tools/gn/item.h"
+#include "tools/gn/location.h"
+
+class ParseNode;
+
+// This class is used by the builder to manage the loading of the dependency
+// tree. It holds a reference to an item and links to other records that the
+// item depends on, both resolved ones, and unresolved ones.
+//
+// If a target depends on another one that hasn't been defined yet, we'll make
+// a placeholder BuilderRecord with no item, and try to load the buildfile
+// associated with the new item. The item will get filled in when we encounter
+// the declaration for the item (or when we're done and realize there are
+// undefined items).
+//
+// You can also have null item pointers when the target is not required for
+// the current build (should_generate is false).
+class BuilderRecord {
+ public:
+  typedef std::set<BuilderRecord*> BuilderRecordSet;
+
+  enum ItemType {
+    ITEM_UNKNOWN,
+    ITEM_TARGET,
+    ITEM_CONFIG,
+    ITEM_TOOLCHAIN
+  };
+
+  //BuilderRecord();
+  BuilderRecord(ItemType type, const Label& label);
+  ~BuilderRecord();
+
+  ItemType type() const { return type_; }
+  const Label& label() const { return label_; }
+
+  // Returns a user-ready name for the given type. e.g. "target".
+  static const char* GetNameForType(ItemType type);
+
+  // Returns true if the given item is of the given type.
+  static bool IsItemOfType(const Item* item, ItemType type);
+
+  // Returns the type enum for the given item.
+  static ItemType TypeOfItem(const Item* item);
+
+  Item* item() { return item_.get(); }
+  const Item* item() const { return item_.get(); }
+  void set_item(scoped_ptr<Item> item) { item_ = item.Pass(); }
+
+  // Indicates from where this item was originally referenced from that caused
+  // it to be loaded. For targets for which we encountered the declaration
+  // before a reference, this will be the empty range.
+  const ParseNode* originally_referenced_from() const {
+    return originally_referenced_from_;
+  }
+  void set_originally_referenced_from(const ParseNode* pn) {
+    originally_referenced_from_ = pn;
+  }
+
+  bool should_generate() const { return should_generate_; }
+  void set_should_generate(bool sg) { should_generate_ = sg; }
+
+  bool resolved() const { return resolved_; }
+  void set_resolved(bool r) { resolved_ = r; }
+
+  bool can_resolve() const {
+    return item_ && unresolved_deps_.empty();
+  }
+
+  // All records this one is depending on.
+  BuilderRecordSet& all_deps() { return all_deps_; }
+  const BuilderRecordSet& all_deps() const { return all_deps_; }
+
+  // Unresolved records this one is depending on. A subset of all... above.
+  BuilderRecordSet& unresolved_deps() { return unresolved_deps_; }
+  const BuilderRecordSet& unresolved_deps() const { return unresolved_deps_; }
+
+  // Records that are waiting on this one to be resolved. This is the other
+  // end of the "unresolved deps" arrow.
+  BuilderRecordSet& waiting_on_resolution() { return waiting_on_resolution_; }
+  const BuilderRecordSet& waiting_on_resolution() const {
+    return waiting_on_resolution_;
+  }
+
+  void AddDep(BuilderRecord* record);
+
+ private:
+  ItemType type_;
+  Label label_;
+  scoped_ptr<Item> item_;
+  const ParseNode* originally_referenced_from_;
+  bool should_generate_;
+  bool resolved_;
+
+  BuilderRecordSet all_deps_;
+  BuilderRecordSet unresolved_deps_;
+  BuilderRecordSet waiting_on_resolution_;
+
+  DISALLOW_COPY_AND_ASSIGN(BuilderRecord);
+};
+
+#endif  // TOOLS_GN_BUILDER_RECORD_H_