Enhance GN introspection

tools/gn/commands.cc

Index: tools/gn/commands.cc
diff --git a/tools/gn/commands.cc b/tools/gn/commands.cc
index ace78a7dff9c2a713e2f92383da72fb711638334..b4f58e3ff85888ef26f50607367075360ef5f60b 100644
--- a/tools/gn/commands.cc
+++ b/tools/gn/commands.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/command_line.h"
+#include "tools/gn/builder.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/filesystem_utils.h"
 #include "tools/gn/item.h"
@@ -13,6 +15,320 @@
 
 namespace commands {
 
+namespace {
+
+// Like above but the input string can be a pattern that matches multiple
+// targets. If the input does not parse as a pattern, prints and error and
+// returns false. If the pattern is valid, fills the vector (which might be
+// empty if there are no matches) and returns true.
+//
+// If all_toolchains is false, a pattern with an unspecified toolchain will
+// match the default toolchain only. If true, all toolchains will be matched.
+bool ResolveTargetsFromCommandLinePattern(
+    Setup* setup,
+    const std::string& label_pattern,
+    bool all_toolchains,
+    std::vector<const Target*>* matches) {
+  Value pattern_value(nullptr, label_pattern);
+
+  Err err;
+  LabelPattern pattern = LabelPattern::GetPattern(
+      SourceDirForCurrentDirectory(setup->build_settings().root_path()),
+      pattern_value,
+      &err);
+  if (err.has_error()) {
+    err.PrintToStdout();
+    return false;
+  }
+
+  if (!all_toolchains) {
+    // By default a pattern with an empty toolchain will match all toolchains.
+    // If the caller wants to default to the main toolchain only, set it
+    // explicitly.
+    if (pattern.toolchain().is_null()) {
+      // No explicit toolchain set.
+      pattern.set_toolchain(setup->loader()->default_toolchain_label());
+    }
+  }
+
+  std::vector<LabelPattern> pattern_vector;
+  pattern_vector.push_back(pattern);
+  FilterTargetsByPatterns(setup->builder()->GetAllResolvedTargets(),
+                          pattern_vector, matches);
+  return true;
+}
+
+
+// If there's an error, it will be printed and false will be returned.
+bool ResolveStringFromCommandLineInput(
+    Setup* setup,
+    const SourceDir& current_dir,
+    const std::string& input,
+    bool all_toolchains,
+    UniqueVector<const Target*>* target_matches,
+    UniqueVector<const Config*>* config_matches,
+    UniqueVector<const Toolchain*>* toolchain_matches,
+    UniqueVector<SourceFile>* file_matches) {
+  if (LabelPattern::HasWildcard(input)) {
+    // For now, only match patterns against targets. It might be nice in the
+    // future to allow the user to specify which types of things they want to
+    // match, but it should probably only match targets by default.
+    std::vector<const Target*> target_match_vector;
+    if (!ResolveTargetsFromCommandLinePattern(setup, input, all_toolchains,
+                                              &target_match_vector))
+      return false;
+    for (const Target* target : target_match_vector)
+      target_matches->push_back(target);
+    return true;
+  }
+
+  // Try to figure out what this thing is.
+  Err err;
+  Label label = Label::Resolve(current_dir,
+                               setup->loader()->default_toolchain_label(),
+                               Value(nullptr, input), &err);
+  if (err.has_error()) {
+    err.PrintToStdout();
+    return false;
+  }
+
+  const Item* item = setup->builder()->GetItem(label);
+  if (item) {
+    if (const Config* as_config = item->AsConfig())
+      config_matches->push_back(as_config);
+    else if (const Target* as_target = item->AsTarget())
+      target_matches->push_back(as_target);
+    else if (const Toolchain* as_toolchain = item->AsToolchain())
+      toolchain_matches->push_back(as_toolchain);
+  } else {
+    // Not an item, assume this must be a file.
+    file_matches->push_back(current_dir.ResolveRelativeFile(
+        input, setup->build_settings().root_path_utf8()));
+  }
+
+  return true;
+}
+
+enum TargetPrintingMode {
+  TARGET_PRINT_BUILDFILE,
+  TARGET_PRINT_LABEL,
+  TARGET_PRINT_OUTPUT,
+};
+
+// Retrieves the target printing mode based on the command line flags for the
+// current process. Returns true on success. On error, prints a message to the
+// console and returns false.
+bool GetTargetPrintingMode(TargetPrintingMode* mode) {
+  std::string switch_key = "as";
+  const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
+
+  if (!cmdline->HasSwitch(switch_key)) {
+    // Default to labels.
+    *mode = TARGET_PRINT_LABEL;
+    return true;
+  }
+
+  std::string value = cmdline->GetSwitchValueASCII(switch_key);
+  if (value == "buildfile") {
+    *mode = TARGET_PRINT_BUILDFILE;
+    return true;
+  }
+  if (value == "label") {
+    *mode = TARGET_PRINT_LABEL;
+    return true;
+  }
+  if (value == "output") {
+    *mode = TARGET_PRINT_OUTPUT;
+    return true;
+  }
+
+  Err(Location(), "Invalid value for \"--as\".",
+      "I was expecting \"buildfile\", \"label\", or \"output\" but you\n"
+      "said \"" + value + "\".").PrintToStdout();
+  return false;
+}
+
+// Returns the target type filter based on the command line flags for the
+// current process. Returns true on success. On error, prints a message to the
+// console and returns false.
+//
+// Target::UNKNOWN will be set if there is no filter. Target::ACTION_FOREACH
+// will never be returned. Code applying the filters should apply Target::ACTION
+// to both ACTION and ACTION_FOREACH.
+bool GetTargetTypeFilter(Target::OutputType* type) {
+  std::string switch_key = "type";
+  const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
+
+  if (!cmdline->HasSwitch(switch_key)) {
+    // Default to unknown -> no filtering.
+    *type = Target::UNKNOWN;
+    return true;
+  }
+
+  std::string value = cmdline->GetSwitchValueASCII(switch_key);
+  if (value == "group") {
+    *type = Target::GROUP;
+    return true;
+  }
+  if (value == "executable") {
+    *type = Target::EXECUTABLE;
+    return true;
+  }
+  if (value == "shared_library") {
+    *type = Target::SHARED_LIBRARY;
+    return true;
+  }
+  if (value == "static_library") {
+    *type = Target::STATIC_LIBRARY;
+    return true;
+  }
+  if (value == "source_set") {
+    *type = Target::SOURCE_SET;
+    return true;
+  }
+  if (value == "copy") {
+    *type = Target::COPY_FILES;
+    return true;
+  }
+  if (value == "action") {
+    *type = Target::ACTION;
+    return true;
+  }
+
+  Err(Location(), "Invalid value for \"--type\".").PrintToStdout();
+  return false;
+}
+
+
+// Applies any testonly filtering specified on the command line to the given
+// target set. On failure, prints an error and returns false.
+bool ApplyTestonlyFilter(std::vector<const Target*>* targets) {
+  const base::CommandLine* cmdline = base::CommandLine::ForCurrentProcess();
+  std::string testonly_key = "testonly";
+
+  if (targets->empty() || !cmdline->HasSwitch(testonly_key))
+    return true;
+
+  std::string testonly_value = cmdline->GetSwitchValueASCII(testonly_key);
+  bool testonly = false;
+  if (testonly_value == "true") {
+    testonly = true;
+  } else if (testonly_value != "false") {
+    Err(Location(), "Bad value for --testonly.",
+        "I was expecting --testonly=true or --testonly=false.")
+        .PrintToStdout();
+    return false;
+  }
+
+  // Filter into a copy of the vector, then swap to output.
+  std::vector<const Target*> result;
+  result.reserve(targets->size());
+
+  for (const Target* target : *targets) {
+    if (target->testonly() == testonly)
+      result.push_back(target);
+  }
+
+  targets->swap(result);
+  return true;
+}
+
+// Applies any target type filtering specified on the command line to the given
+// target set. On failure, prints an error and returns false.
+bool ApplyTypeFilter(std::vector<const Target*>* targets) {
+  Target::OutputType type = Target::UNKNOWN;
+  if (!GetTargetTypeFilter(&type))
+    return false;
+  if (targets->empty() || type == Target::UNKNOWN)
+    return true;  // Nothing to filter out.
+
+  // Filter into a copy of the vector, then swap to output.
+  std::vector<const Target*> result;
+  result.reserve(targets->size());
+
+  for (const Target* target : *targets) {
+    // Make "action" also apply to ACTION_FOREACH.
+    if (target->output_type() == type ||
+        (type == Target::ACTION &&
+         target->output_type() == Target::ACTION_FOREACH))
+      result.push_back(target);
+  }
+
+  targets->swap(result);
+  return true;
+}
+
+// Returns the file path generating this item.
+base::FilePath BuildFileForItem(const Item* item) {
+  return item->defined_from()->GetRange().begin().file()->physical_name();
+}
+
+void PrintTargetsAsBuildfiles(bool indent,
+                              const std::vector<const Target*>& targets) {
+  // Output the set of unique source files.
+  std::set<std::string> unique_files;
+  for (const Target* target : targets)
+    unique_files.insert(FilePathToUTF8(BuildFileForItem(target)));
+
+  for (const std::string& file : unique_files) {
+    if (indent)
+      OutputString("  ");
+    OutputString(file + "\n");
+  }
+}
+
+void PrintTargetsAsLabels(bool indent,
+                          const std::vector<const Target*>& targets) {
+  // Putting the labels into a set automatically sorts them for us.
+  std::set<Label> unique_labels;
+  for (const auto& target : targets)
+    unique_labels.insert(target->label());
+
+  // Grab the label of the default toolchain from the first target.
+  Label default_tc_label =
+      targets[0]->settings()->default_toolchain_label();
+
+  for (const Label& label : unique_labels) {
+    // Print toolchain only for ones not in the default toolchain.
+    if (indent)
+      OutputString("  ");
+    OutputString(label.GetUserVisibleName(
+        label.GetToolchainLabel() != default_tc_label));
+    OutputString("\n");
+  }
+}
+
+void PrintTargetsAsOutputs(bool indent,
+                           const std::vector<const Target*>& targets) {
+  if (targets.empty())
+    return;
+
+  // Grab the build settings from a random target.
+  const BuildSettings* build_settings =
+      targets[0]->settings()->build_settings();
+
+  SourceDir current_dir = SourceDirForCurrentDirectory(
+      build_settings->root_path());
+  for (const Target* target : targets) {
+    // Use the link output file if there is one, otherwise fall back to the
+    // dependency output file (for actions, for example).
+    OutputFile output_file = target->link_output_file();
+    if (output_file.value().empty())
+      output_file = target->dependency_output_file();
+
+    SourceFile output_as_source =
+        output_file.AsSourceFile(build_settings);
+    std::string result = RebasePath(output_as_source.value(), current_dir,
+                                    build_settings->root_path_utf8());
+    if (indent)
+      OutputString("  ");
+    OutputString(result);
+    OutputString("\n");
+  }
+}
+
+}  // namespace
+
 CommandInfo::CommandInfo()
     : help_short(nullptr),
       help(nullptr),
@@ -84,38 +400,87 @@ const Target* ResolveTargetFromCommandLineString(
   return target;
 }
 
-bool ResolveTargetsFromCommandLinePattern(
+bool ResolveFromCommandLineInput(
     Setup* setup,
-    const std::string& label_pattern,
+    const std::vector<std::string>& input,
     bool all_toolchains,
-    std::vector<const Target*>* matches) {
-  Value pattern_value(nullptr, label_pattern);
-
-  Err err;
-  LabelPattern pattern = LabelPattern::GetPattern(
-      SourceDirForCurrentDirectory(setup->build_settings().root_path()),
-      pattern_value,
-      &err);
-  if (err.has_error()) {
-    err.PrintToStdout();
+    UniqueVector<const Target*>* target_matches,
+    UniqueVector<const Config*>* config_matches,
+    UniqueVector<const Toolchain*>* toolchain_matches,
+    UniqueVector<SourceFile>* file_matches) {
+  if (input.empty()) {
+    Err(Location(), "You need to specify a label, file, or pattern.")
+        .PrintToStdout();
     return false;
   }
 
-  if (!all_toolchains) {
-    // By default a pattern with an empty toolchain will match all toolchains.
-    // IF the caller wants to default to the main toolchain only, set it
-    // explicitly.
-    if (pattern.toolchain().is_null()) {
-      // No explicit toolchain set.
-      pattern.set_toolchain(setup->loader()->default_toolchain_label());
+  SourceDir cur_dir =
+      SourceDirForCurrentDirectory(setup->build_settings().root_path());
+  for (const auto& cur : input) {
+    if (!ResolveStringFromCommandLineInput(setup, cur_dir, cur,
+                                           all_toolchains, target_matches,
+                                           config_matches, toolchain_matches,
+                                           file_matches))
+      return false;
+  }
+  return true;
+}
+
+void FilterTargetsByPatterns(const std::vector<const Target*>& input,
+                             const std::vector<LabelPattern>& filter,
+                             std::vector<const Target*>* output) {
+  for (const auto& target : input) {
+    for (const auto& pattern : filter) {
+      if (pattern.Matches(target->label())) {
+        output->push_back(target);
+        break;
+      }
     }
   }
+}
 
-  std::vector<LabelPattern> pattern_vector;
-  pattern_vector.push_back(pattern);
-  FilterTargetsByPatterns(setup->builder()->GetAllResolvedTargets(),
-                          pattern_vector, matches);
-  return true;
+void FilterTargetsByPatterns(const std::vector<const Target*>& input,
+                             const std::vector<LabelPattern>& filter,
+                             UniqueVector<const Target*>* output) {
+  for (const auto& target : input) {
+    for (const auto& pattern : filter) {
+      if (pattern.Matches(target->label())) {
+        output->push_back(target);
+        break;
+      }
+    }
+  }
+}
+
+void FilterAndPrintTargets(bool indent, std::vector<const Target*>* targets) {
+  if (targets->empty())
+    return;
+
+  if (!ApplyTestonlyFilter(targets))
+    return;
+  if (!ApplyTypeFilter(targets))
+    return;
+
+  TargetPrintingMode printing_mode = TARGET_PRINT_LABEL;
+  if (targets->empty() || !GetTargetPrintingMode(&printing_mode))
+    return;
+  switch (printing_mode) {
+    case TARGET_PRINT_BUILDFILE:
+      PrintTargetsAsBuildfiles(indent, *targets);
+      break;
+    case TARGET_PRINT_LABEL:
+      PrintTargetsAsLabels(indent, *targets);
+      break;
+    case TARGET_PRINT_OUTPUT:
+      PrintTargetsAsOutputs(indent, *targets);
+      break;
+  }
+}
+
+void FilterAndPrintTargetSet(bool indent,
+                             const std::set<const Target*>& targets) {
+  std::vector<const Target*> target_vector(targets.begin(), targets.end());
+  FilterAndPrintTargets(indent, &target_vector);
 }
 
 }  // namespace commands