loader.cc revision f2477e01787aa58f445919b809d89e252beef54f 
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#include "tools/gn/loader.h"
6
7#include "base/bind.h"
8#include "base/message_loop/message_loop.h"
9#include "base/stl_util.h"
10#include "tools/gn/build_settings.h"
11#include "tools/gn/err.h"
12#include "tools/gn/filesystem_utils.h"
13#include "tools/gn/input_file_manager.h"
14#include "tools/gn/parse_tree.h"
15#include "tools/gn/scheduler.h"
16#include "tools/gn/scope_per_file_provider.h"
17#include "tools/gn/settings.h"
18#include "tools/gn/source_dir.h"
19#include "tools/gn/source_file.h"
20#include "tools/gn/trace.h"
21
22namespace {
23
24std::string GetOutputSubdirName(const Label& toolchain_label, bool is_default) {
25  // The default toolchain has no subdir.
26  if (is_default)
27    return std::string();
28
29  // For now just assume the toolchain name is always a valid dir name. We may
30  // want to clean up the in the future.
31  return toolchain_label.name();
32}
33
34}  // namespace
35
36// Identifies one time a file is loaded in a given toolchain so we don't load
37// it more than once.
38struct LoaderImpl::LoadID {
39  LoadID() {}
40  LoadID(const SourceFile& f, const Label& tc_name)
41      : file(f),
42        toolchain_name(tc_name) {
43  }
44
45  bool operator<(const LoadID& other) const {
46    if (file.value() == other.file.value())
47      return toolchain_name < other.toolchain_name;
48    return file < other.file;
49  }
50
51  SourceFile file;
52  Label toolchain_name;
53};
54
55// Our tracking information for a toolchain.
56struct LoaderImpl::ToolchainRecord {
57  // The default toolchain label can be empty for the first time the default
58  // toolchain is loaded, since we don't know it yet. This will be fixed up
59  // later. It should be valid in all other cases.
60  ToolchainRecord(const BuildSettings* build_settings,
61                  const Label& toolchain_label,
62                  const Label& default_toolchain_label)
63      : settings(build_settings,
64                 GetOutputSubdirName(toolchain_label,
65                     toolchain_label == default_toolchain_label)),
66        is_toolchain_loaded(false),
67        is_config_loaded(false) {
68    settings.set_default_toolchain_label(default_toolchain_label);
69    settings.set_toolchain_label(toolchain_label);
70  }
71
72  Settings settings;
73
74  bool is_toolchain_loaded;
75  bool is_config_loaded;
76
77  std::vector<SourceFile> waiting_on_me;
78};
79
80// -----------------------------------------------------------------------------
81
82const void* Loader::kDefaultToolchainKey = &kDefaultToolchainKey;
83
84Loader::Loader() {
85}
86
87Loader::~Loader() {
88}
89
90void Loader::Load(const Label& label) {
91  Load(BuildFileForLabel(label), label.GetToolchainLabel());
92}
93
94// static
95SourceFile Loader::BuildFileForLabel(const Label& label) {
96  return SourceFile(label.dir().value() + "BUILD.gn");
97}
98
99// -----------------------------------------------------------------------------
100
101LoaderImpl::LoaderImpl(const BuildSettings* build_settings)
102    : main_loop_(base::MessageLoop::current()),
103      pending_loads_(0),
104      build_settings_(build_settings) {
105}
106
107LoaderImpl::~LoaderImpl() {
108  STLDeleteContainerPairSecondPointers(toolchain_records_.begin(),
109                                       toolchain_records_.end());
110}
111
112void LoaderImpl::Load(const SourceFile& file,
113    const Label& in_toolchain_name) {
114  const Label& toolchain_name = in_toolchain_name.is_null()
115      ? default_toolchain_label_ : in_toolchain_name;
116  LoadID load_id(file, toolchain_name);
117  if (!invocations_.insert(load_id).second)
118    return;  // Already in set, so this file was already loaded or schedulerd.
119
120  if (toolchain_records_.empty()) {
121    // Nothing loaded, need to load the default build config. The intial load
122    // should not specify a toolchain.
123    DCHECK(toolchain_name.is_null());
124
125    ToolchainRecord* record =
126        new ToolchainRecord(build_settings_, Label(), Label());
127    toolchain_records_[Label()] = record;
128
129    // The default build config is no dependent on the toolchain definition,
130    // since we need to load the build config before we know what the default
131    // toolchain name is.
132    record->is_toolchain_loaded = true;
133
134    record->waiting_on_me.push_back(file);
135    ScheduleLoadBuildConfig(&record->settings, Scope::KeyValueMap());
136    return;
137  }
138
139  ToolchainRecord* record;
140  if (toolchain_name.is_null())
141    record = toolchain_records_[default_toolchain_label_];
142  else
143    record = toolchain_records_[toolchain_name];
144
145  if (!record) {
146    DCHECK(!default_toolchain_label_.is_null());
147
148    // No reference to this toolchain found yet, make one.
149    record = new ToolchainRecord(build_settings_, toolchain_name,
150                                 default_toolchain_label_);
151    toolchain_records_[toolchain_name] = record;
152
153    // Schedule a load of the toolchain using the default one.
154    Load(BuildFileForLabel(toolchain_name), default_toolchain_label_);
155  }
156
157  if (record->is_config_loaded)
158    ScheduleLoadFile(&record->settings, file);
159  else
160    record->waiting_on_me.push_back(file);
161}
162
163void LoaderImpl::ToolchainLoaded(const Toolchain* toolchain) {
164  ToolchainRecord* record = toolchain_records_[toolchain->label()];
165  if (!record) {
166    DCHECK(!default_toolchain_label_.is_null());
167    record = new ToolchainRecord(build_settings_, toolchain->label(),
168                                 default_toolchain_label_);
169    toolchain_records_[toolchain->label()] = record;
170  }
171  record->is_toolchain_loaded = true;
172
173  // The default build config is loaded first, then its toolchain. Secondary
174  // ones are loaded in the opposite order so we can pass toolchain parameters
175  // to the build config. So we may or may not have a config at this point.
176  if (!record->is_config_loaded) {
177    ScheduleLoadBuildConfig(&record->settings, toolchain->args());
178  } else {
179    // There should be nobody waiting on this if the build config is already
180    // loaded.
181    DCHECK(record->waiting_on_me.empty());
182  }
183}
184
185Label LoaderImpl::GetDefaultToolchain() const {
186  return default_toolchain_label_;
187}
188
189const Settings* LoaderImpl::GetToolchainSettings(const Label& label) {
190  ToolchainRecordMap::iterator found_toolchain;
191  if (label.is_null()) {
192    if (default_toolchain_label_.is_null())
193      return NULL;
194    found_toolchain = toolchain_records_.find(default_toolchain_label_);
195  } else {
196    found_toolchain = toolchain_records_.find(label);
197  }
198
199  if (found_toolchain == toolchain_records_.end())
200    return NULL;
201  return &found_toolchain->second->settings;
202}
203
204void LoaderImpl::ScheduleLoadFile(const Settings* settings,
205                                  const SourceFile& file) {
206  Err err;
207  pending_loads_++;
208  if (!AsyncLoadFile(LocationRange(), settings->build_settings(), file,
209                     base::Bind(&LoaderImpl::BackgroundLoadFile, this,
210                                settings, file),
211                     &err)) {
212    g_scheduler->FailWithError(err);
213    DecrementPendingLoads();
214  }
215}
216
217void LoaderImpl::ScheduleLoadBuildConfig(
218    Settings* settings,
219    const Scope::KeyValueMap& toolchain_overrides) {
220  Err err;
221  pending_loads_++;
222  if (!AsyncLoadFile(LocationRange(), settings->build_settings(),
223                     settings->build_settings()->build_config_file(),
224                     base::Bind(&LoaderImpl::BackgroundLoadBuildConfig,
225                                this, settings, toolchain_overrides),
226                     &err)) {
227    g_scheduler->FailWithError(err);
228    DecrementPendingLoads();
229  }
230}
231
232void LoaderImpl::BackgroundLoadFile(const Settings* settings,
233                                    const SourceFile& file_name,
234                                    const ParseNode* root) {
235  if (!root) {
236    main_loop_->PostTask(FROM_HERE,
237        base::Bind(&LoaderImpl::DecrementPendingLoads, this));
238    return;
239  }
240
241  if (g_scheduler->verbose_logging()) {
242    g_scheduler->Log("Running", file_name.value() + " with toolchain " +
243                     settings->toolchain_label().GetUserVisibleName(false));
244  }
245
246  Scope our_scope(settings->base_config());
247  ScopePerFileProvider per_file_provider(&our_scope);
248  our_scope.set_source_dir(file_name.GetDir());
249
250  ScopedTrace trace(TraceItem::TRACE_FILE_EXECUTE, file_name.value());
251  trace.SetToolchain(settings->toolchain_label());
252
253  Err err;
254  root->Execute(&our_scope, &err);
255  if (err.has_error())
256    g_scheduler->FailWithError(err);
257
258  trace.Done();
259
260  main_loop_->PostTask(FROM_HERE, base::Bind(&LoaderImpl::DidLoadFile, this));
261}
262
263void LoaderImpl::BackgroundLoadBuildConfig(
264    Settings* settings,
265    const Scope::KeyValueMap& toolchain_overrides,
266    const ParseNode* root) {
267  if (!root) {
268    main_loop_->PostTask(FROM_HERE,
269        base::Bind(&LoaderImpl::DecrementPendingLoads, this));
270    return;
271  }
272
273  Scope* base_config = settings->base_config();
274  base_config->set_source_dir(SourceDir("//"));
275
276  settings->build_settings()->build_args().SetupRootScope(
277      base_config, toolchain_overrides);
278
279  base_config->SetProcessingBuildConfig();
280
281  // See kDefaultToolchainKey in the header.
282  Label default_toolchain_label;
283  if (settings->is_default())
284    base_config->SetProperty(kDefaultToolchainKey, &default_toolchain_label);
285
286  ScopedTrace trace(TraceItem::TRACE_FILE_EXECUTE,
287      settings->build_settings()->build_config_file().value());
288  trace.SetToolchain(settings->toolchain_label());
289
290  const BlockNode* root_block = root->AsBlock();
291  Err err;
292  root_block->ExecuteBlockInScope(base_config, &err);
293
294  trace.Done();
295
296  base_config->ClearProcessingBuildConfig();
297  if (settings->is_default()) {
298    // The default toolchain must have been set in the default build config
299    // file.
300    if (default_toolchain_label.is_null()) {
301      g_scheduler->FailWithError(Err(Location(),
302          "The default build config file did not call set_default_toolchain()",
303          "If you don't call this, I can't figure out what toolchain to use\n"
304          "for all of this code."));
305    } else {
306      DCHECK(settings->toolchain_label().is_null());
307      settings->set_toolchain_label(default_toolchain_label);
308    }
309  }
310
311  main_loop_->PostTask(FROM_HERE,
312      base::Bind(&LoaderImpl::DidLoadBuildConfig, this,
313                 settings->toolchain_label()));
314}
315
316void LoaderImpl::DidLoadFile() {
317  DecrementPendingLoads();
318}
319
320void LoaderImpl::DidLoadBuildConfig(const Label& label) {
321  // Do not return early, we must call DecrementPendingLoads() at the bottom.
322
323  ToolchainRecordMap::iterator found_toolchain = toolchain_records_.find(label);
324  ToolchainRecord* record = NULL;
325  if (found_toolchain == toolchain_records_.end()) {
326    // When loading the default build config, we'll insert it into the record
327    // map with an empty label since we don't yet know what to call it.
328    //
329    // In this case, we should have exactly one entry in the map with an empty
330    // label. We now need to fix up the naming so it refers to the "real" one.
331    CHECK(toolchain_records_.size() == 1);
332    ToolchainRecordMap::iterator empty_label = toolchain_records_.find(Label());
333    CHECK(empty_label != toolchain_records_.end());
334
335    // Fix up the toolchain record.
336    record = empty_label->second;
337    toolchain_records_[label] = record;
338    toolchain_records_.erase(empty_label);
339
340    // Save the default toolchain label.
341    default_toolchain_label_ = label;
342    DCHECK(record->settings.default_toolchain_label().is_null());
343    record->settings.set_default_toolchain_label(label);
344
345    // The settings object should have the toolchain label already set.
346    DCHECK(!record->settings.toolchain_label().is_null());
347
348    // Update any stored invocations that refer to the empty toolchain label.
349    // This will normally only be one, for the root build file, so brute-force
350    // is OK.
351    LoadIDSet old_loads;
352    invocations_.swap(old_loads);
353    for (LoadIDSet::iterator i = old_loads.begin();
354         i != old_loads.end(); ++i) {
355      if (i->toolchain_name.is_null()) {
356        // Fix up toolchain label
357        invocations_.insert(LoadID(i->file, label));
358      } else {
359        // Can keep the old one.
360        invocations_.insert(*i);
361      }
362    }
363  } else {
364    record = found_toolchain->second;
365  }
366
367  DCHECK(!record->is_config_loaded);
368  DCHECK(record->is_toolchain_loaded);
369  record->is_config_loaded = true;
370
371  // Schedule all waiting file loads.
372  for (size_t i = 0; i < record->waiting_on_me.size(); i++)
373    ScheduleLoadFile(&record->settings, record->waiting_on_me[i]);
374  record->waiting_on_me.clear();
375
376  DecrementPendingLoads();
377}
378
379void LoaderImpl::DecrementPendingLoads() {
380  DCHECK(pending_loads_ > 0);
381  pending_loads_--;
382  if (pending_loads_ == 0 && !complete_callback_.is_null())
383    complete_callback_.Run();
384}
385
386bool LoaderImpl::AsyncLoadFile(
387    const LocationRange& origin,
388    const BuildSettings* build_settings,
389    const SourceFile& file_name,
390    const base::Callback<void(const ParseNode*)>& callback,
391    Err* err) {
392  if (async_load_file_.is_null()) {
393    return g_scheduler->input_file_manager()->AsyncLoadFile(
394        origin, build_settings, file_name, callback, err);
395  }
396  return async_load_file_.Run(
397      origin, build_settings, file_name, callback, err);
398}
399