Add runtime dependency extraction for GN.

tools/gn/command_desc.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 #include <set>
 #include <sstream>
 
 #include "base/command_line.h"
 #include "tools/gn/commands.h"
 #include "tools/gn/config.h"
 #include "tools/gn/config_values_extractors.h"
 #include "tools/gn/deps_iterator.h"
 #include "tools/gn/filesystem_utils.h"
 #include "tools/gn/item.h"
 #include "tools/gn/label.h"
+#include "tools/gn/runtime_deps.h"
 #include "tools/gn/setup.h"
 #include "tools/gn/standard_out.h"
 #include "tools/gn/substitution_writer.h"
 #include "tools/gn/target.h"
 #include "tools/gn/variables.h"
 
 namespace commands {
 
 namespace {
 
+// The switch for displaying blame.
+const char kBlame[] = "blame";
+
 // Prints the given directory in a nice way for the user to view.
 std::string FormatSourceDir(const SourceDir& dir) {
 #if defined(OS_WIN)
   // On Windows we fix up system absolute paths to look like native ones.
   // Internally, they'll look like "/C:\foo\bar/"
   if (dir.is_system_absolute()) {
     std::string buf = dir.value();
     if (buf.size() > 3 && buf[2] == ':') {
       buf.erase(buf.begin());  // Erase beginning slash.
       return buf;
@@ skipping 360 matching lines @@
   }
 };
 
 // Writes a given config value type to the string, optionally with attribution.
 // This should match RecursiveTargetConfigToStream in the order it traverses.
 template<typename T> void OutputRecursiveTargetConfig(
     const Target* target,
     const char* header_name,
     const std::vector<T>& (ConfigValues::* getter)() const) {
   bool display_blame =
-      base::CommandLine::ForCurrentProcess()->HasSwitch("blame");
+      base::CommandLine::ForCurrentProcess()->HasSwitch(kBlame);
 
   DescValueWriter<T> writer;
   std::ostringstream out;
 
   for (ConfigValuesIterator iter(target); !iter.done(); iter.Next()) {
     if ((iter.cur().*getter)().empty())
       continue;
 
     // Optional blame sub-head.
     if (display_blame) {
@@ skipping 12 matching lines @@
     ConfigValuesToStream(iter.cur(), getter, writer, out);
   }
 
   std::string out_str = out.str();
   if (!out_str.empty()) {
     OutputString("\n" + std::string(header_name) + "\n");
     OutputString(out_str);
   }
 }
 
+void PrintRuntimeDeps(const Target* target) {
+  bool display_blame =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(kBlame);
+  Label toolchain = target->label().GetToolchainLabel();
+
+  const Target* previous_from = NULL;
+  for (const auto& pair : ComputeRuntimeDeps(target)) {
+    if (display_blame) {
+      // Generally a target's runtime deps will be listed sequentially, so
+      // group them and don't duplicate the "from" label for two in a row.
+      if (previous_from == pair.second) {
+        OutputString("  ");  // Just indent.
+      } else {
+        previous_from = pair.second;
+        OutputString("From ");
+        OutputString(pair.second->label().GetUserVisibleName(toolchain));
+        OutputString("\n  ");  // Make the file name indented.
+      }
+    }
+    OutputString(pair.first.value());
+    OutputString("\n");
+  }
+}
+
 }  // namespace
 
 // desc ------------------------------------------------------------------------
 
 const char kDesc[] = "desc";
 const char kDesc_HelpShort[] =
     "desc: Show lots of insightful information about a target.";
 const char kDesc_Help[] =
     "gn desc <out_dir> <target label> [<what to show>] [--blame]\n"
     "\n"
@@ skipping 57 matching lines @@
     "  include_dirs  [--blame]\n"
     "  cflags        [--blame]\n"
     "  cflags_cc     [--blame]\n"
     "  cflags_cxx    [--blame]\n"
     "  ldflags       [--blame]\n"
     "  lib_dirs\n"
     "  libs\n"
     "      Shows the given values taken from the target and all configs\n"
     "      applying. See \"--blame\" below.\n"
     "\n"
+    "  runtime_deps\n"
+    "      Compute all runtime deps for the given target. This is a\n"
+    "      computed list and does not correspond to any GN variable, unlike\n"
+    "      most other values here.\n"
+    "\n"
+    "      The output is a list of file names relative to the build\n"
+    "      directory. See \"gn help runtime_deps\" for how this is computed.\n"
+    "      This also works with \"--blame\" to see the source of the\n"
+    "      dependency.\n"
+    "\n"
+    "Shared flags\n"
+    "\n"
     "  --blame\n"
     "      Used with any value specified by a config, this will name\n"
     "      the config that specified the value. This doesn't currently work\n"
     "      for libs and lib_dirs because those are inherited and are more\n"
     "      complicated to figure out the blame (patches welcome).\n"
     "\n"
     "Flags that control how deps are printed\n"
     "\n"
     "  --all\n"
     "      Collects all recursive dependencies and prints a sorted flat list.\n"
@@ skipping 94 matching lines @@
     } else if (what == variables::kDepfile) {
       PrintDepfile(target, false);
     } else if (what == variables::kOutputs) {
       PrintOutputs(target, false);
     } else if (what == variables::kDeps) {
       PrintDeps(target, false);
     } else if (what == variables::kLibDirs) {
       PrintLibDirs(target, false);
     } else if (what == variables::kLibs) {
       PrintLibs(target, false);
+    } else if (what == "runtime_deps") {
+      PrintRuntimeDeps(target);
 
     CONFIG_VALUE_HANDLER(defines, std::string)
     CONFIG_VALUE_HANDLER(include_dirs, SourceDir)
     CONFIG_VALUE_HANDLER(cflags, std::string)
     CONFIG_VALUE_HANDLER(cflags_c, std::string)
     CONFIG_VALUE_HANDLER(cflags_cc, std::string)
     CONFIG_VALUE_HANDLER(cflags_objc, std::string)
     CONFIG_VALUE_HANDLER(cflags_objcc, std::string)
     CONFIG_VALUE_HANDLER(ldflags, std::string)
 
@@ skipping 75 matching lines @@
   // so always display them, even for groups and such.
   PrintLibs(target, true);
   PrintLibDirs(target, true);
 
   PrintDeps(target, true);
 
   return 0;
 }
 
 }  // namespace commands