add diff tool (flutter#19)

* add diff tool
rhencke · Jun 15, 2017 · dfcbd59 · dfcbd59
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.5.5
+
+- Added `diff` tool.
+
 ## 0.5.4+2
 
 - Updated minimum SDK dependency to align with package dependencies.

diff --git a/README.md b/README.md
@@ -63,6 +63,10 @@ The following tools are a available today:
     dependency between functions and fields in your program. Currently it only
     supports the `some_path` query, which shows a dependency path from one
     function to another.
+
+  * [`diff`][diff]: a tool that diffs two info files and reports which
+    program elements have been added, removed, or changed size. This also
+    tells which elements are no longer deferred or have become deferred.
 
   * [`library_size_split`][lib_split]: a tool that shows how much code was
     attributed to each library. This tool is configurable so it can group data
@@ -102,10 +106,10 @@ this tool only supports the `some_path` query, which gives you the shortest path
 for how one function depends on another.
 
 Run this tool as follows:
-```bash
+```console
 # activate is only needed once to install the dart2js_info* executables
-pub global activate dart2js_info
-dart2js_info_code_deps out.js.info.json some_path main foo
+$ pub global activate dart2js_info
+$ dart2js_info_code_deps out.js.info.json some_path main foo
 ```
 
 The arguments to the query are regular expressions that can be used to
@@ -120,22 +124,58 @@ a fully qualified element name, which includes the library and class name
 If the name of a function your are looking for is unique enough, it might be
 sufficient to just write that name as your regular expression.
 
+### Diff tool
+
+This command-line tool shows a diff between two info files. It can be run
+as follows:
+
+```console
+$ pub global activate dart2js_info # only needed once
+$ dart2js_info_diff old.js.info.json new.js.info.json
+```
+
+The tool gives a breakdown of the difference between the two info files.
+Here's an example output:
+
+```
+OVERALL SIZE DIFFERENCE
+========================================================================
+3 bytes
+
+ADDED
+========================================================================
+
+REMOVED
+========================================================================
+file:///home/het/Code/foo/foo.dart::A.y: 0 bytes
+
+CHANGED SIZE
+========================================================================
+
+BECAME DEFERRED
+========================================================================
+
+NO LONGER DEFERRED
+========================================================================
+
+```
+
 ### Library size split tool
 
 This command-line tool shows the size distribution of generated code among
 libraries. It can be run as follows:
 
-```bash
-pub global activate dart2js_info # only needed once
-dart2js_info_library_size_split out.js.info.json
+```console
+$ pub global activate dart2js_info # only needed once
+$ dart2js_info_library_size_split out.js.info.json
 ```
 
 
 Libraries can be grouped using regular expressions. You can
 specify what regular expressions to use by providing a `grouping.yaml` file:
 
-```bash
-dart2js_info_library_size_split out.js.info.json grouping.yaml
+```console
+$ dart2js_info_library_size_split out.js.info.json grouping.yaml
 ```
 
 The format of the `grouping.yaml` file is as follows:
@@ -205,9 +245,9 @@ bootstrapping code and lazy static initializers are missing.
 This tool checks that the output from dart2js meets a given specification,
 given in a YAML file. It can be run as follows:
 
-```bash
-pub global activate dart2js_info # only needed once
-dart2js_info_deferred_library_check out.js.info.json manifest.yaml
+```console
+$ pub global activate dart2js_info # only needed once
+$ dart2js_info_deferred_library_check out.js.info.json manifest.yaml
 ```
 
 The format of the YAML file is:
@@ -253,7 +293,7 @@ This tool gives a breakdown of all of the deferred code in the program by size.
 It can show how much of the total code size is deferred. It can be run as
 follows:
 
-```bash
+```console
 pub global activate dart2js_info # only needed once
 dart2js_info_deferred_library_size out.js.info.json
 ```
@@ -278,9 +318,9 @@ Percent of code deferred                  41.86%
 This tool reports which code is included in each output unit.  It can be run as
 follows:
 
-```bash
-pub global activate dart2js_info # only needed once
-dart2js_info_deferred_library_layout out.js.info.json
+```console
+$ pub global activate dart2js_info # only needed once
+$ dart2js_info_deferred_library_layout out.js.info.json
 ```
 
 The tool will output a table listing all of the deferred output units or chunks,
@@ -322,9 +362,9 @@ code of your application.  We use dependency information to compute dominance
 and reachability data as well.
 
 When you run:
-```bash
-pub global activate dart2js_info # only needed once
-dart2js_info_function_size_analysis out.js.info.json
+```console
+$ pub global activate dart2js_info # only needed once
+$ dart2js_info_function_size_analysis out.js.info.json
 ```
 
 the tool produces a table output with lots of entries. Here is an example entry
@@ -355,8 +395,8 @@ steps are as follows:
   * Compile an app with dart2js using `--dump-info` and defining the
     Dart environment `traceCalls=post`:
 
-```
-DART_VM_OPTIONS="-DtraceCalls=post" dart2js --dump-info main.dart
+```console
+$ DART_VM_OPTIONS="-DtraceCalls=post" dart2js --dump-info main.dart
 ```
 
   Because coverage/tracing data is currently experimental, the feature is
@@ -365,8 +405,8 @@ DART_VM_OPTIONS="-DtraceCalls=post" dart2js --dump-info main.dart
 
   * Launch the coverage server tool to serve up the JS code of your app:
 
-```bash
-dart2js_info_coverage_log_server main.dart.js
+```console
+$ dart2js_info_coverage_log_server main.dart.js
 ```
 
   * (optional) If you have a complex application setup, you may need to serve an
@@ -382,8 +422,8 @@ dart2js_info_coverage_log_server main.dart.js
   * Finally, run the live code analysis tool given it both the info and
     coverage json files:
 
-```bash
-dart2js_info_live_code_size_analysis main.dart.info.json main.dart.coverage.json
+```console
+$ dart2js_info_live_code_size_analysis main.dart.info.json main.dart.coverage.json
 ```
 
 ## Code location, features and bugs
@@ -394,6 +434,7 @@ bugs at the [issue tracker][tracker].
 [repo]: https://github.com/dart-lang/dart2js_info/
 [tracker]: https://github.com/dart-lang/dart2js_info/issues
 [code_deps]: https://github.com/dart-lang/dart2js_info/blob/master/bin/code_deps.dart
+[diff]: https://github.com/dart-lang/dart2js_info/blob/master/bin/diff.dart
 [lib_split]: https://github.com/dart-lang/dart2js_info/blob/master/bin/library_size_split.dart
 [deferred_lib]: https://github.com/dart-lang/dart2js_info/blob/master/bin/deferred_library_check.dart
 [deferred_size]: https://github.com/dart-lang/dart2js_info/blob/master/bin/deferred_library_size.dart

diff --git a/bin/diff.dart b/bin/diff.dart
@@ -0,0 +1,92 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:dart2js_info/src/diff.dart';
+import 'package:dart2js_info/src/util.dart';
+
+/// A command-line tool that computes the diff between two info files.
+main(List<String> args) async {
+  if (args.length != 2) {
+    print('usage: dart2js_info_diff old.info.json new.info.json');
+    return;
+  }
+  var oldInfo = await infoFromFile(args[0]);
+  var newInfo = await infoFromFile(args[1]);
+
+  var diffs = diff(oldInfo, newInfo);
+
+  // Categorize the diffs
+  var adds = <AddDiff>[];
+  var removals = <RemoveDiff>[];
+  var sizeChanges = <SizeDiff>[];
+  var becameDeferred = <DeferredStatusDiff>[];
+  var becameUndeferred = <DeferredStatusDiff>[];
+
+  for (var diff in diffs) {
+    switch (diff.kind) {
+      case DiffKind.add:
+        adds.add(diff as AddDiff);
+        break;
+      case DiffKind.remove:
+        removals.add(diff as RemoveDiff);
+        break;
+      case DiffKind.size:
+        sizeChanges.add(diff as SizeDiff);
+        break;
+      case DiffKind.deferred:
+        var deferredDiff = diff as DeferredStatusDiff;
+        if (deferredDiff.wasDeferredBefore) {
+          becameUndeferred.add(deferredDiff);
+        } else {
+          becameDeferred.add(deferredDiff);
+        }
+        break;
+    }
+  }
+
+  // TODO(het): Improve this output. Siggi has good suggestions in
+  // https://github.com/dart-lang/dart2js_info/pull/19
+  var overallSizeDiff = newInfo.program.size - oldInfo.program.size;
+  _section('OVERALL SIZE DIFFERENCE');
+  print('$overallSizeDiff bytes');
+  print('');
+
+  _section('ADDED');
+  for (var add in adds) {
+    print('${longName(add.info, useLibraryUri: true)}: ${add.info.size} bytes');
+  }
+  print('');
+
+  _section('REMOVED');
+  for (var removal in removals) {
+    print('${longName(removal.info, useLibraryUri: true)}: '
+        '${removal.info.size} bytes');
+  }
+  print('');
+
+  _section('CHANGED SIZE');
+  for (var sizeChange in sizeChanges) {
+    print('${longName(sizeChange.info, useLibraryUri: true)}: '
+        '${sizeChange.sizeDifference} bytes');
+  }
+  print('');
+
+  _section('BECAME DEFERRED');
+  for (var diff in becameDeferred) {
+    print('${longName(diff.info, useLibraryUri: true)}: '
+        '${diff.info.size} bytes');
+  }
+  print('');
+
+  _section('NO LONGER DEFERRED');
+  for (var diff in becameUndeferred) {
+    print('${longName(diff.info, useLibraryUri: true)}: '
+        '${diff.info.size} bytes');
+  }
+}
+
+void _section(String title) {
+  print(title);
+  print('=' * 72);
+}
diff --git a/lib/info.dart b/lib/info.dart
@@ -46,7 +46,7 @@ abstract class Info {
   /// Info of the enclosing element.
   Info parent;
 
-  dynamic accept(InfoVisitor visitor);
+  T accept<T>(InfoVisitor<T> visitor);
 }
 
 /// Common information used for most kind of elements.
@@ -171,7 +171,7 @@ class AllInfo {
 
   AllInfo();
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitAll(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitAll(this);
 }
 
 class ProgramInfo {
@@ -196,7 +196,7 @@ class ProgramInfo {
       this.noSuchMethodEnabled,
       this.minified});
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitProgram(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitProgram(this);
 }
 
 /// Info associated with a library element.
@@ -229,7 +229,7 @@ class LibraryInfo extends BasicInfo {
 
   LibraryInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitLibrary(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitLibrary(this);
 }
 
 /// Information about an output unit. Normally there is just one for the entire
@@ -244,7 +244,7 @@ class OutputUnitInfo extends BasicInfo {
 
   OutputUnitInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitOutput(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitOutput(this);
 }
 
 /// Information about a class element.
@@ -267,7 +267,7 @@ class ClassInfo extends BasicInfo {
 
   ClassInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitClass(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitClass(this);
 }
 
 /// Information about a constant value.
@@ -282,7 +282,7 @@ class ConstantInfo extends BasicInfo {
 
   ConstantInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitConstant(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitConstant(this);
 }
 
 /// Information about a field element.
@@ -319,7 +319,7 @@ class FieldInfo extends BasicInfo with CodeInfo {
 
   FieldInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitField(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitField(this);
 }
 
 /// Information about a typedef declaration.
@@ -332,7 +332,7 @@ class TypedefInfo extends BasicInfo {
 
   TypedefInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitTypedef(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitTypedef(this);
 }
 
 /// Information about a function or method.
@@ -396,7 +396,7 @@ class FunctionInfo extends BasicInfo with CodeInfo {
 
   FunctionInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitFunction(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitFunction(this);
 }
 
 /// Information about a closure, also known as a local function.
@@ -410,7 +410,7 @@ class ClosureInfo extends BasicInfo {
 
   ClosureInfo._(String serializedId) : super._fromId(serializedId);
 
-  dynamic accept(InfoVisitor visitor) => visitor.visitClosure(this);
+  T accept<T>(InfoVisitor<T> visitor) => visitor.visitClosure(this);
 }
 
 /// Information about how a dependency is used.