DDC: mostly incremental compilation, fixes #223

lib/src/options.dart

Index: lib/src/options.dart
diff --git a/lib/src/options.dart b/lib/src/options.dart
index 3fa1334431d8c67b0b344c02ed77b13647447861..5245cc7cf3a8c6edd5bbdf870defe59213ca5f18 100644
--- a/lib/src/options.dart
+++ b/lib/src/options.dart
@@ -145,6 +145,10 @@ class CompilerOptions {
   /// to this directory.
   final String inputBaseDir;
 
+  /// True to save compiler messages to a file.
+  /// Useful for incremental compilation and tests.
+  final bool saveMessages;
+
   CompilerOptions(
       {this.strongOptions: const StrongModeOptions(),
       this.sourceOptions: const SourceResolverOptions(),
@@ -162,8 +166,9 @@ class CompilerOptions {
       this.host: 'localhost',
       this.port: 8080,
       this.runtimeDir,
-      this.inputs,
-      this.inputBaseDir});
+      this.inputs: const [],
+      this.inputBaseDir,
+      this.saveMessages: false});
 }
 
 /// Parses options from the command-line
@@ -191,7 +196,7 @@ CompilerOptions parseOptions(List<String> argv, {bool forceOutDir: false}) {
   }
   var runtimeDir = args['runtime-dir'];
   if (runtimeDir == null) {
-    runtimeDir = _computeRuntimeDir();
+    runtimeDir = _computedRuntimeDir;
   }
   var outputDir = args['out'];
   if (outputDir == null && (serverMode || forceOutDir)) {
@@ -248,6 +253,7 @@ CompilerOptions parseOptions(List<String> argv, {bool forceOutDir: false}) {
       host: args['host'],
       port: int.parse(args['port']),
       runtimeDir: runtimeDir,
+      saveMessages: args['save-messages'],
       inputs: args.rest);
 }
 
@@ -315,12 +321,16 @@ final ArgParser argParser = StrongModeOptions.addArguments(new ArgParser()
   ..addOption('dump-info-file',
       abbr: 'f',
       help: 'Dump info json file (requires dump-info)',
-      defaultsTo: null));
+      defaultsTo: null)
+  ..addFlag('save-messages', help: 'Save compiler messages to a text file'));
 
 /// Tries to find the `lib/runtime/` directory of the dev_compiler package. This
 /// works when running devc from it's sources or from a snapshot that is
 /// activated via `pub global activate`.
-String _computeRuntimeDir() {
+final String _computedRuntimeDir = () {
+  // TODO(jmesserly): if we're in the test runner we can't get our runtime path.
+  if (Platform.script.scheme == 'data') return null;
+
   var scriptPath = path.fromUri(Platform.script);
   var file = path.basename(scriptPath);
   var dir = path.dirname(scriptPath);
@@ -367,4 +377,20 @@ String _computeRuntimeDir() {
     return path.join(dir, cacheDir, 'lib', 'runtime');
   }
   return null;
-}
+}();
+
+/// The timestamp of the compiler itself. Used to invalidate output if the
+/// compiler itself changes.

[Leaf, 2015/09/04 21:46:31]

At some point, we should probably include a version string in the generated code
so that we could invalidate even if we can't find the compiler sources.  Maybe a
TODO?

+final DateTime compilerLastModified = () {
+  if (_computedRuntimeDir == null) return null;
+
+  DateTime lastModify = null;
+  var compilerLib = new Directory(path.join(_computedRuntimeDir, '..'));
+  for (var file in compilerLib.listSync(recursive: true)) {
+    if (file is File && file.path.endsWith('.dart')) {
+      var modify = file.lastModifiedSync();
+      if (lastModify == null || modify.isAfter(lastModify)) lastModify = modify;
+    }
+  }
+  return lastModify;
+}();