ninja: rules chained only by output of first one failing

pylib/gyp/generator/ninja.py

Index: pylib/gyp/generator/ninja.py
diff --git a/pylib/gyp/generator/ninja.py b/pylib/gyp/generator/ninja.py
index 19dcc1bb7fe788a0323c5de4946ee84350b21e59..c069ee66d4f0f17a1f59865d77acdb9b4586f423 100644
--- a/pylib/gyp/generator/ninja.py
+++ b/pylib/gyp/generator/ninja.py
@@ -314,6 +314,48 @@ class NinjaWriter:
       self.ninja.newline()
     return targets[0]
 
+  def _SourcesHandledByRule(self, rule, sources):
+    """Get a list of files that from |sources| that |rule| handles."""
+    rule_ext = rule['extension']
+    result = []
+    for source in sources:
+      if source.endswith('.' + rule_ext):
+        inputs, outputs = self._GetInputsAndOutputsForRule(rule, source)
+        if source in outputs:
+          # Don't include the outputs of this rule, even if by extension we
+          # ought to.
+          continue
+        result.append(source)
+    return result
+
+  def _GetInputsAndOutputsForRule(self, rule, source):
+    """Get the expanded inputs and outputs of the given |rule| for a
+    particular |source|."""
+    dirname, basename = os.path.split(source)
+    root, ext = os.path.splitext(basename)
+    outputs = [self.ExpandRuleVariables(o, root, dirname,
+                                        source, ext, basename)
+               for o in rule['outputs']]
+    inputs = [self.ExpandRuleVariables(i, root, dirname,
+                                       source, ext, basename)
+              for i in rule.get('inputs', [])]
+    return inputs, outputs
+
+  def _GetSources(self, spec):
+    """Get all sources for the given |spec|. In addition to the sources
+    directly specified in the gyp file, it includes sources generated by
+    actions and copies. Outputs of rules are not included because otherwise
+    rules that generate the same extension as they process cause much
+    confusion. Rule outputs are added when the rule is processed."""
+    sources = spec.get('sources', [])
+    for action in spec.get('actions', []):
+      if int(action.get('process_outputs_as_sources', False)):
+        sources.extend(action.get('outputs', []))
+    for copy in spec.get('copies', []):
+      sources.extend(copy.get('files', []))
+    return set(sources)
+
+
   def WriteSpec(self, spec, config_name, generator_flags):
     """The main entry point for NinjaWriter: write the build rules for a spec.
 
@@ -359,13 +401,16 @@ class NinjaWriter:
       self.target.preaction_stamp = actions_depends
       self.target.precompile_stamp = compile_depends
 
+    # Build a list of sources. We do this as a pre-process so that we have
+    # access to generated outputs for actions for other actions and rules.
+    sources = self._GetSources(spec)
+
     # Write out actions, rules, and copies.  These must happen before we
     # compile any sources, so compute a list of predependencies for sources
     # while we do it.
-    extra_sources = []
     mac_bundle_depends = []
     self.target.actions_stamp = self.WriteActionsRulesCopies(
-        spec, extra_sources, actions_depends, mac_bundle_depends)
+        spec, sources, actions_depends, mac_bundle_depends)
 
     # If we have actions/rules/copies, we depend directly on those, but
     # otherwise we depend on dependent target's actions/rules/copies etc.
@@ -375,7 +420,6 @@ class NinjaWriter:
 
     # Write out the compilation steps, if any.
     link_deps = []
-    sources = spec.get('sources', []) + extra_sources
     if sources:
       link_deps = self.WriteSources(
           config_name, config, sources, compile_depends_stamp,
@@ -447,7 +491,7 @@ class NinjaWriter:
       self._WinIdlRule(source, prebuild, outputs)
     return outputs
 
-  def WriteActionsRulesCopies(self, spec, extra_sources, prebuild,
+  def WriteActionsRulesCopies(self, spec, sources, prebuild,
                               mac_bundle_depends):
     """Write out the Actions, Rules, and Copies steps.  Return a path
     representing the outputs of these steps."""
@@ -455,10 +499,10 @@ class NinjaWriter:
     extra_mac_bundle_resources = []
 
     if 'actions' in spec:
-      outputs += self.WriteActions(spec['actions'], extra_sources, prebuild,
+      outputs += self.WriteActions(spec['actions'], sources, prebuild,
                                    extra_mac_bundle_resources)
     if 'rules' in spec:
-      outputs += self.WriteRules(spec['rules'], extra_sources, prebuild,
+      outputs += self.WriteRules(spec['rules'], sources, prebuild,
                                  extra_mac_bundle_resources)
     if 'copies' in spec:
       outputs += self.WriteCopies(spec['copies'], prebuild)
@@ -490,7 +534,7 @@ class NinjaWriter:
     else:
       return '%s %s: %s' % (verb, self.name, fallback)
 
-  def WriteActions(self, actions, extra_sources, prebuild,
+  def WriteActions(self, actions, sources, prebuild,
                    extra_mac_bundle_resources):
     # Actions cd into the base directory.
     env = self.GetXcodeEnv()
@@ -512,8 +556,6 @@ class NinjaWriter:
                                          is_cygwin, env=env)
 
       inputs = [self.GypPathToNinja(i, env) for i in action['inputs']]
-      if int(action.get('process_outputs_as_sources', False)):
-        extra_sources += action['outputs']
       if int(action.get('process_outputs_as_mac_bundle_resources', False)):
         extra_mac_bundle_resources += action['outputs']
       outputs = [self.GypPathToNinja(o, env) for o in action['outputs']]
@@ -527,8 +569,7 @@ class NinjaWriter:
 
     return all_outputs
 
-  def WriteRules(self, rules, extra_sources, prebuild,
-                 extra_mac_bundle_resources):
+  def WriteRules(self, rules, sources, prebuild, extra_mac_bundle_resources):
     all_outputs = []
     for rule in rules:
       # First write out a rule for the rule action.
@@ -562,21 +603,15 @@ class NinjaWriter:
           return path.replace('\\', '/')
         return path
 
+      rule_sources = self._SourcesHandledByRule(rule, sources)
       # For each source file, write an edge that generates all the outputs.
-      for source in rule.get('rule_sources', []):
+      for source in rule_sources:
         dirname, basename = os.path.split(source)
         root, ext = os.path.splitext(basename)
-
-        # Gather the list of inputs and outputs, expanding $vars if possible.
-        outputs = [self.ExpandRuleVariables(o, root, dirname,
-                                            source, ext, basename)
-                   for o in rule['outputs']]
-        inputs = [self.ExpandRuleVariables(i, root, dirname,
-                                           source, ext, basename)
-                  for i in rule.get('inputs', [])]
+        inputs, outputs = self._GetInputsAndOutputsForRule(rule, source)
 
         if int(rule.get('process_outputs_as_sources', False)):
-          extra_sources += outputs
+          sources.update(outputs)
         if int(rule.get('process_outputs_as_mac_bundle_resources', False)):
           extra_mac_bundle_resources += outputs