Add "-i" to command line to specify leading indent.

Fix #464.

R=sigmund@google.com

Review URL: https://codereview.chromium.org//1470263004 .

bin/format.dart

@@ -25,6 +25,8 @@ void main(List<String> args) {
       negatable: false, help: "Shows version information.");
   parser.addOption("line-length",
       abbr: "l", help: "Wrap lines longer than this.", defaultsTo: "80");
+  parser.addOption("indent",
+      abbr: "i", help: "Spaces of leading indentation.", defaultsTo: "0");
   parser.addOption("preserve",
       help: 'Selection to preserve, formatted as "start:length".');
   parser.addFlag("dry-run",
@@ -118,7 +120,6 @@ void main(List<String> args) {
   }
 
   var pageWidth;
-
   try {
     pageWidth = int.parse(argResults["line-length"]);
   } on FormatException catch (_) {
@@ -128,10 +129,22 @@ void main(List<String> args) {
         '"${argResults['line-length']}".');
   }
 
+  var indent;
+
+  try {
+    indent = int.parse(argResults["indent"]);
+    if (indent < 0 || indent.toInt() != indent) throw new FormatException();
+  } on FormatException catch (_) {
+    usageError(
+        parser,
+        '--indent must be a non-negative integer, was '
+        '"${argResults['indent']}".');
+  }
+
   var followLinks = argResults["follow-links"];
 
   var options = new FormatterOptions(reporter,
-      pageWidth: pageWidth, followLinks: followLinks);
+      indent: indent, pageWidth: pageWidth, followLinks: followLinks);
 
   if (argResults.rest.isEmpty) {
     formatStdin(options, selection);
@@ -168,7 +181,8 @@ void formatStdin(FormatterOptions options, List<int> selection) {
 
   var input = new StringBuffer();
   stdin.transform(new Utf8Decoder()).listen(input.write, onDone: () {
-    var formatter = new DartFormatter(pageWidth: options.pageWidth);
+    var formatter =
+        new DartFormatter(indent: options.indent, pageWidth: options.pageWidth);
     try {
       options.reporter.beforeFile(null, "<stdin>");
       var source = new SourceCode(input.toString(),

lib/src/formatter_options.dart

@@ -14,6 +14,9 @@ class FormatterOptions {
   /// The [OutputReporter] used to show the formatting results.
   final OutputReporter reporter;
 
+  /// The number of spaces of indentation to prefix the output with.
+  final int indent;
+
   /// The number of columns that formatted output should be constrained to fit
   /// within.
   final int pageWidth;
@@ -22,7 +25,7 @@ class FormatterOptions {
   final bool followLinks;
 
   FormatterOptions(this.reporter,
-      {this.pageWidth: 80, this.followLinks: false});
+      {this.indent: 0, this.pageWidth: 80, this.followLinks: false});
 }
 
 /// How the formatter reports the results it produces.

lib/src/io.dart

@@ -67,7 +67,8 @@ bool processDirectory(FormatterOptions options, Directory directory) {
 bool processFile(FormatterOptions options, File file, {String label}) {
   if (label == null) label = file.path;
 
-  var formatter = new DartFormatter(pageWidth: options.pageWidth);
+  var formatter =
+      new DartFormatter(indent: options.indent, pageWidth: options.pageWidth);
   try {
     var source = new SourceCode(file.readAsStringSync(), uri: file.path);
     options.reporter.beforeFile(file, label);

test/command_line_test.dart

@@ -16,54 +16,54 @@ import 'utils.dart';
 void main() {
   setUpTestSuite();
 
-  test("Exits with 0 on success.", () {
+  test("exits with 0 on success", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatterOnDir();
     process.shouldExit(0);
   });
 
-  test("Exits with 64 on a command line argument error.", () {
+  test("exits with 64 on a command line argument error", () {
     var process = runFormatterOnDir(["-wat"]);
     process.shouldExit(64);
   });
 
-  test("Exits with 65 on a parse error.", () {
+  test("exits with 65 on a parse error", () {
     d.dir("code", [d.file("a.dart", "herp derp i are a dart")]).create();
 
     var process = runFormatterOnDir();
     process.shouldExit(65);
   });
 
-  test("Errors if --dry-run and --overwrite are both passed.", () {
+  test("errors if --dry-run and --overwrite are both passed", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatterOnDir(["--dry-run", "--overwrite"]);
     process.shouldExit(64);
   });
 
-  test("Errors if --dry-run and --machine are both passed.", () {
+  test("errors if --dry-run and --machine are both passed", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatterOnDir(["--dry-run", "--machine"]);
     process.shouldExit(64);
   });
 
-  test("Errors if --machine and --overwrite are both passed.", () {
+  test("errors if --machine and --overwrite are both passed", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatterOnDir(["--machine", "--overwrite"]);
     process.shouldExit(64);
   });
 
-  test("Errors if --dry-run and --machine are both passed.", () {
+  test("errors if --dry-run and --machine are both passed", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatter(["--dry-run", "--machine"]);
     process.shouldExit(64);
   });
 
-  test("Errors if --machine and --overwrite are both passed.", () {
+  test("errors if --machine and --overwrite are both passed", () {
     d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
     var process = runFormatter(["--machine", "--overwrite"]);
@@ -94,7 +94,7 @@ void main() {
   });
 
   group("--dry-run", () {
-    test("prints names of files that would change.", () {
+    test("prints names of files that would change", () {
       d.dir("code", [
         d.file("a_bad.dart", unformattedSource),
         d.file("b_good.dart", formattedSource),
@@ -113,7 +113,7 @@ void main() {
       process.shouldExit();
     });
 
-    test("does not modify files.", () {
+    test("does not modify files", () {
       d.dir("code", [d.file("a.dart", unformattedSource)]).create();
 
       var process = runFormatterOnDir(["--dry-run"]);
@@ -153,25 +153,25 @@ void main() {
   });
 
   group("--preserve", () {
-    test("errors if given paths.", () {
+    test("errors if given paths", () {
       var process = runFormatter(["--preserve", "path", "another"]);
       process.shouldExit(64);
     });
 
-    test("errors on wrong number of components.", () {
+    test("errors on wrong number of components", () {
       var process = runFormatter(["--preserve", "1"]);
       process.shouldExit(64);
 
       process = runFormatter(["--preserve", "1:2:3"]);
       process.shouldExit(64);
     });
 
-    test("errors on non-integer component.", () {
+    test("errors on non-integer component", () {
       var process = runFormatter(["--preserve", "1:2.3"]);
       process.shouldExit(64);
     });
 
-    test("updates selection.", () {
+    test("updates selection", () {
       var process = runFormatter(["--preserve", "6:10", "-m"]);
       process.writeLine(unformattedSource);
       process.closeStdin();
@@ -187,20 +187,43 @@ void main() {
     });
   });
 
+  group("--indent", () {
+    test("sets the leading indentation of the output", () {
+      var process = runFormatter(["--indent", "3"]);
+      process.writeLine("main() {'''");
+      process.writeLine("a flush left multi-line string''';}");
+      process.closeStdin();
+
+      process.stdout.expect("   main() {");
+      process.stdout.expect("     '''");
+      process.stdout.expect("a flush left multi-line string''';");
+      process.stdout.expect("   }");
+      process.shouldExit(0);
+    });
+
+    test("errors if the indent is not a non-negative number", () {
+      var process = runFormatter(["--indent", "notanum"]);
+      process.shouldExit(64);
+
+      process = runFormatter(["--preserve", "-4"]);
+      process.shouldExit(64);
+    });
+  });
+
   group("with no paths", () {
-    test("errors on --overwrite.", () {
+    test("errors on --overwrite", () {
       var process = runFormatter(["--overwrite"]);
       process.shouldExit(64);
     });
 
-    test("exits with 65 on parse error.", () {
+    test("exits with 65 on parse error", () {
       var process = runFormatter();
       process.writeLine("herp derp i are a dart");
       process.closeStdin();
       process.shouldExit(65);
     });
 
-    test("reads from stdin.", () {
+    test("reads from stdin", () {
       var process = runFormatter();
       process.writeLine(unformattedSource);
       process.closeStdin();