1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef TOOLS_GN_ITEM_TREE_H_ 6 #define TOOLS_GN_ITEM_TREE_H_ 7 8 #include "base/containers/hash_tables.h" 9 #include "base/memory/scoped_ptr.h" 10 #include "base/synchronization/lock.h" 11 #include "tools/gn/label.h" 12 13 class BuildSettings; 14 class Err; 15 class Item; 16 class ItemNode; 17 18 // Represents the full dependency tree if labeled items in the system. 19 // Generally you will interact with this through the target manager, etc. 20 // 21 // There are two modes for filling out the dependency tree: 22 // 23 // - In greedy mode, every target we encounter will be generated. This means 24 // that we'll recursively load all of its subdependencies. So if you have 25 // a build file that's loaded for any reason, all targets in that build file 26 // will be generated. 27 // 28 // - In non-greedy mode, we'll only generate and load dependncies for targets 29 // that have the should_generate bit set. This allows us to load the minimal 30 // set of buildfiles required for one or more targets. 31 // 32 // The main build is generally run in greedy mode, since people expect to be 33 // be able to write random tests and have them show up in the output. We'll 34 // switch into non-greed mode when doing diagnostics (like displaying the 35 // dependency tree on the command line) and for dependencies on targets in 36 // other toolchains. The toolchain behavior is important, if target A depends 37 // on B with an alternate toolchain, it doesn't mean we should recursively 38 // generate all targets in the buildfile just to get B: we should generate the 39 // and load the minimum number of files in order to resolve B. 40 class ItemTree { 41 public: 42 ItemTree(); 43 ~ItemTree(); 44 45 // This lock must be held when calling the "Locked" functions below. 46 base::Lock& lock() const { return lock_; } 47 48 // Returns NULL if the item is not found. 49 // 50 // The lock must be held. 51 ItemNode* GetExistingNodeLocked(const Label& label); 52 53 // There must not be an item with this label in the tree already. Takes 54 // ownership of the pointer. 55 // 56 // The lock must be held. 57 void AddNodeLocked(ItemNode* node); 58 59 // Mark the given item as being defined. If it has no unresolved 60 // dependencies, it will be marked resolved, and the resolved state will be 61 // recursively pushed into the dependency tree. Returns an error if there was 62 // an error. 63 bool MarkItemDefinedLocked(const BuildSettings* build_settings, 64 const Label& label, 65 Err* err); 66 67 // Fills the given vector with all known items. 68 void GetAllItemsLocked(std::vector<const Item*>* dest) const; 69 70 // Returns an error if there are unresolved dependencies, or no error if 71 // there aren't. 72 // 73 // The lock should not be held. 74 Err CheckForBadItems() const; 75 76 private: 77 void MarkItemResolvedLocked(ItemNode* node); 78 79 // Given a set of unresolved nodes, looks for cycles and returns the error 80 // message describing any cycles it found. 81 std::string CheckForCircularDependenciesLocked( 82 const std::vector<const ItemNode*>& bad_nodes) const; 83 84 mutable base::Lock lock_; 85 86 typedef base::hash_map<Label, ItemNode*> StringToNodeHash; 87 StringToNodeHash items_; // Owning pointer. 88 89 DISALLOW_COPY_AND_ASSIGN(ItemTree); 90 }; 91 92 #endif // TOOLS_GN_ITEM_TREE_H_ 93
