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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 GetAllItemNodesLocked(std::vector<const ItemNode*>* dest) const; | |
69 void GetAllItemsLocked(std::vector<const Item*>* dest) const; | |
70 | |
71 // Returns an error if there are unresolved dependencies, or no error if | |
72 // there aren't. | |
73 // | |
74 // The lock should not be held. | |
75 Err CheckForBadItems() const; | |
76 | |
77 private: | |
78 void MarkItemResolvedLocked(ItemNode* node); | |
79 | |
80 // Given a set of unresolved nodes, looks for cycles and returns the error | |
81 // message describing any cycles it found. | |
82 std::string CheckForCircularDependenciesLocked( | |
83 const std::vector<const ItemNode*>& bad_nodes) const; | |
84 | |
85 mutable base::Lock lock_; | |
86 | |
87 typedef base::hash_map<Label, ItemNode*> StringToNodeHash; | |
88 StringToNodeHash items_; // Owning pointer. | |
89 | |
90 DISALLOW_COPY_AND_ASSIGN(ItemTree); | |
91 }; | |
92 | |
93 #endif // TOOLS_GN_ITEM_TREE_H_ | |
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