🚙 GN: Add write_runtime_deps variable

tools/gn/scheduler.cc

Index: tools/gn/scheduler.cc
diff --git a/tools/gn/scheduler.cc b/tools/gn/scheduler.cc
index dfc877d190bc1522f6f035432c8f6469fd4e2af0..cef2b9bddc54b9b7ab0ab24bb6a051df74ca8305 100644
--- a/tools/gn/scheduler.cc
+++ b/tools/gn/scheduler.cc
@@ -12,6 +12,7 @@
 #include "build/build_config.h"
 #include "tools/gn/standard_out.h"
 #include "tools/gn/switches.h"
+#include "tools/gn/target.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
@@ -153,6 +154,28 @@ void Scheduler::AddUnknownGeneratedInput(const Target* target,
   unknown_generated_inputs_.insert(std::make_pair(file, target));
 }
 
+void Scheduler::AddWriteRuntimeDepsTarget(const Target* target) {
+  base::AutoLock lock(lock_);
+  write_runtime_deps_targets_.push_back(target);
+}
+
+std::vector<const Target*> Scheduler::GetWriteRuntimeDepsTargets()
+    const {

[brettw, 2016/03/28 23:06:35]

const can be on previous line.

[agrieve, 2016/03/29 16:14:01]

Done.

+  base::AutoLock lock(lock_);
+  return write_runtime_deps_targets_;
+}
+
+bool Scheduler::IsFileGeneratedByWriteRuntimeDeps(
+    const OutputFile& file) const {
+  // Number of targets should be quite small, so brute-force search is fine.
+  for (const Target* target : write_runtime_deps_targets_) {

[brettw, 2016/03/28 23:06:35]

This will crash because it accesses the list not protected by the lock. I don't
think we want to lock here if we can avoid it anyway since this can be called a
lot.

target.cc is already going through all the deps tree. I didn't entirely consider
the details of the changes you made to the deps walking algorithm there but I
wonder if it can be modified to handle all the cases without doing this code.

[agrieve, 2016/03/29 16:14:01]

Added the lock.

This function is called only when the initial
EnsureFileIsGeneratedByDependency() fails, so it shouldn't be called a lot.

+    if (file == target->write_runtime_deps_output()) {
+      return true;
+    }
+  }
+  return false;
+}
+
 std::multimap<SourceFile, const Target*>
     Scheduler::GetUnknownGeneratedInputs() const {
   base::AutoLock lock(lock_);