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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_TOOLCHAIN_MANAGER_H_ | |
| 6 #define TOOLS_GN_TOOLCHAIN_MANAGER_H_ | |
| 7 | |
| 8 #include <map> | |
| 9 | |
| 10 #include "base/basictypes.h" | |
| 11 #include "base/synchronization/lock.h" | |
| 12 #include "tools/gn/label.h" | |
| 13 #include "tools/gn/location.h" | |
| 14 #include "tools/gn/source_file.h" | |
| 15 #include "tools/gn/toolchain.h" | |
| 16 | |
| 17 class Err; | |
| 18 class BuildSettings; | |
| 19 class ParseNode; | |
| 20 class Settings; | |
| 21 | |
| 22 // The toolchain manager manages the mapping of toolchain names to the | |
| 23 // settings and toolchain object. It also loads build files in the context of a | |
| 24 // toolchain context of a toolchain, and manages running the build config | |
| 25 // script when necessary. | |
| 26 // | |
| 27 // This class uses the lock from the item tree to manage threadsafety. The | |
| 28 // functions requiring this lock to be held are named "Locked" to make this | |
| 29 // more clear. The "Unlocked" versions will acquire the lock themselves so will | |
| 30 // break if you call it while locked. (The rationale behind which is which is | |
| 31 // just based on the needs of the callers, so it can be changed.) There are two | |
| 32 // reasons for this: | |
| 33 // | |
| 34 // The first is that when resolving a target, we do a bunch of script | |
| 35 // stuff (slow) and then lookup the target, config, and toolchain dependencies | |
| 36 // based on that. The options are to do a lock around each dependency lookup | |
| 37 // or do a lock around the entire operation. Given that there's not a huge | |
| 38 // amount of work, the "big lock" approach is likely a bit better since it | |
| 39 // avoids lots of locking overhead. | |
| 40 // | |
| 41 // The second reason is that if we had a separate lock here, we would need to | |
| 42 // lock around creating a new toolchain. But creating a new toolchain involves | |
| 43 // adding it to the item tree, and this needs to be done atomically to prevent | |
| 44 // other threads from seeing a partially initialized toolchain. This sets up | |
| 45 // having deadlock do to acquiring multiple locks, or recursive locking | |
| 46 // problems. | |
| 47 class ToolchainManager { | |
| 48 public: | |
| 49 ToolchainManager(const BuildSettings* build_settings); | |
| 50 ~ToolchainManager(); | |
| 51 | |
| 52 // At the very beginning of processing, this begins loading build files. | |
| 53 // This will scheduler loadin the default build config and the given build | |
| 54 // file in that context, going out from there. | |
| 55 // | |
| 56 // This returns immediately, you need to run the Scheduler to actually | |
| 57 // process anything. It's assumed this function is called on the main thread | |
| 58 // before doing anything, so it does not need locking. | |
| 59 void StartLoadingUnlocked(const SourceFile& build_file_name); | |
| 60 | |
| 61 // Returns the settings object for a given toolchain. This does not | |
| 62 // schedule loading the given toolchain if it's not loaded yet: you actually | |
| 63 // need to invoke a target with that toolchain to get that. | |
| 64 // | |
| 65 // On error, returns NULL and sets the error. | |
| 66 const Settings* GetSettingsForToolchainLocked(const LocationRange& from_here, | |
| 67 const Label& toolchain_name, | |
| 68 Err* err); | |
| 69 | |
| 70 // Returns the toolchain definition or NULL if the toolchain hasn't been | |
| 71 // defined yet. | |
| 72 const Toolchain* GetToolchainDefinitionUnlocked(const Label& toolchain_name); | |
| 73 | |
| 74 // Sets the default toolchain. If the default toolchain is already set, | |
| 75 // this function will return false and fill in the given err. | |
| 76 bool SetDefaultToolchainUnlocked(const Label& dt, | |
| 77 const LocationRange& defined_from, | |
| 78 Err* err); | |
| 79 | |
| 80 // Returns the default toolchain name. This will be empty if it hasn't been | |
| 81 // set. | |
| 82 Label GetDefaultToolchainUnlocked() const; | |
| 83 | |
| 84 // Saves the given named toolchain (the name will be taken from the toolchain | |
| 85 // parameter). This will fail and return false if the given toolchain was | |
| 86 // already defined. In this case, the given error will be set. | |
| 87 bool SetToolchainDefinitionLocked(const Toolchain& tc, | |
| 88 const LocationRange& defined_from, | |
| 89 Err* err); | |
| 90 | |
| 91 // Schedules an invocation of the given file under the given toolchain. The | |
| 92 // toolchain file will be loaded if necessary. If the toolchain is an is_null | |
| 93 // label, the default toolchain will be used. | |
| 94 // | |
| 95 // The origin should be the node that will be blamed for this invocation if | |
| 96 // an error occurs. If a synchronous error occurs, the given error will be | |
| 97 // set and it will return false. If an async error occurs, the error will be | |
| 98 // sent to the scheduler. | |
| 99 bool ScheduleInvocationLocked(const LocationRange& origin, | |
| 100 const Label& toolchain_name, | |
| 101 const SourceDir& dir, | |
| 102 Err* err); | |
| 103 | |
| 104 private: | |
| 105 struct Info; | |
| 106 | |
| 107 static std::string ToolchainToOutputSubdir(const Label& toolchain_name); | |
| 108 | |
| 109 // Creates a new info struct and saves it in the map. A pointer to the | |
| 110 // struct is returned. No loads are scheduled. | |
| 111 // | |
| 112 // If the label is non-empty, the toolchain will be added to the ItemTree | |
| 113 // so that other nodes can depend on it. THe empty label case is for the | |
| 114 // default build config file (when the toolchain name isn't known yet). It | |
| 115 // will be added later. | |
| 116 // | |
| 117 // On error, will return NULL and the error will be set. | |
| 118 Info* LoadNewToolchainLocked(const LocationRange& specified_from, | |
| 119 const Label& toolchain_name, | |
| 120 Err* err); | |
| 121 | |
| 122 // Fixes up the default toolchain names once they're known when processing | |
| 123 // the default build config, or throw an error if the default toolchain | |
| 124 // hasn't been set. See the StartLoading() implementation for more. | |
| 125 void FixupDefaultToolchainLocked(); | |
| 126 | |
| 127 // Schedules the buildfile to be invoked for the given toolchain info. The | |
| 128 // toolchain must be already loaded. Can be called with the lock held or not | |
| 129 // (it does not use any class vars). | |
| 130 bool ScheduleBackgroundInvoke(Info* info, | |
| 131 const LocationRange& specified_from, | |
| 132 const SourceFile& build_file, | |
| 133 Err* err); | |
| 134 | |
| 135 // Schedules the build config file for the given info to be loaded and | |
| 136 // invoked. The toolchain definition (for non-default toolchains) should | |
| 137 // already be loaded. | |
| 138 bool ScheduleBuildConfigLoadLocked(Info* info, bool is_default, Err* err); | |
| 139 | |
| 140 // Invokes the given file for a toolchain with loaded settings. Run on a | |
| 141 // background thread asynchronously. | |
| 142 void BackgroundInvoke(const Info* info, | |
| 143 const SourceFile& file_name, | |
| 144 const ParseNode* root); | |
| 145 | |
| 146 // Loads the build config file for the given Info. | |
| 147 void BackgroundLoadBuildConfig(Info* info, | |
| 148 bool is_default, | |
| 149 const ParseNode* root); | |
| 150 | |
| 151 // Returns the lock to use. | |
| 152 base::Lock& GetLock() const; | |
| 153 | |
| 154 const BuildSettings* build_settings_; | |
| 155 | |
| 156 // We own the info pointers. | |
| 157 typedef std::map<Label, Info*> ToolchainMap; | |
| 158 ToolchainMap toolchains_; | |
| 159 | |
| 160 Label default_toolchain_; | |
| 161 LocationRange default_toolchain_defined_here_; | |
| 162 | |
| 163 typedef std::map<std::pair<SourceFile, const Info*>, Info*> | |
| 164 BuildConfigInvokeMap; | |
| 165 BuildConfigInvokeMap pending_build_config_map_; | |
| 166 | |
| 167 DISALLOW_COPY_AND_ASSIGN(ToolchainManager); | |
| 168 }; | |
| 169 | |
| 170 #endif // TOOLS_GN_TOOLCHAIN_MANAGER_H_ | |
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