Add TextPosition.== and hashCode, and some text API docs (#4283)

lib/ui/natives.dart

@@ -5,7 +5,7 @@
 part of dart.ui;
 
 // Corelib 'print' implementation.
-void _print(arg) {
+void _print(dynamic arg) {
   _Logger._printString(arg.toString());
 }
 
@@ -43,13 +43,13 @@ Uri _getBaseURL() => Uri.parse(_baseURL);
 // Required for gen_snapshot to work correctly.
 int _isolateId;
 
-_getPrintClosure() => _print;
-_getScheduleMicrotaskClosure() => _scheduleMicrotask;
-_getGetBaseURLClosure() => _getBaseURL;
+Function _getPrintClosure() => _print;
+Function _getScheduleMicrotaskClosure() => _scheduleMicrotask;
+Function _getGetBaseURLClosure() => _getBaseURL;
 
 // Though the "main" symbol is not included in any of the libraries imported
 // above, the builtin library will be included manually during VM setup. This
 // symbol is only necessary for precompilation. It is marked as a stanalone
 // entry point into the VM. This prevents the precompiler from tree shaking
 // away "main"
-_getMainClosure() => main;
+Function _getMainClosure() => main;

lib/ui/text.dart

@@ -154,17 +154,18 @@ class TextDecoration {
   /// Draw a line through each line of text
   static const TextDecoration lineThrough = const TextDecoration._(0x4);
 
+  @override
   bool operator ==(dynamic other) {
-    if (identical(this, other))
-      return true;
     if (other is! TextDecoration)
       return false;
     final TextDecoration typedOther = other;
     return _mask == typedOther._mask;
   }
 
+  @override
   int get hashCode => _mask.hashCode;
 
+  @override
   String toString() {
     if (_mask == 0)
       return 'TextDecoration.none';
@@ -652,7 +653,10 @@ enum TextDirection {
 }
 
 /// A rectangle enclosing a run of text.
+///
+/// This is similar to [Rect] but includes an inherent [TextDirection].
 class TextBox {
+  /// Creates an object that describes a box containing text.
   const TextBox.fromLTRBD(
     this.left,
     this.top,
@@ -670,12 +674,16 @@ class TextBox {
   ) : direction = TextDirection.values[directionIndex];
 
   /// The left edge of the text box, irrespective of direction.
+  ///
+  /// To get the leading edge (which may depend on the [direction]), consider [start].
   final double left;
 
   /// The top edge of the text box.
   final double top;
 
   /// The right edge of the text box, irrespective of direction.
+  ///
+  /// To get the trailing edge (which may depend on the [direction]), consider [end].
   final double right;
 
   /// The bottom edge of the text box.
@@ -687,16 +695,25 @@ class TextBox {
   /// Returns a rect of the same size as this box.
   Rect toRect() => new Rect.fromLTRB(left, top, right, bottom);
 
-  /// The left edge of the box for ltr text; the right edge of the box for rtl text.
+  /// The [left] edge of the box for left-to-right text; the [right] edge of the box for right-to-left text.
+  ///
+  /// See also:
+  ///
+  ///  * [direction], which specifies the text direction.
   double get start {
     return (direction == TextDirection.ltr) ? left : right;
   }
 
-  /// The right edge of the box for ltr text; the left edge of the box for rtl text.
+  /// The [right] edge of the box for left-to-right text; the [left] edge of the box for right-to-left text.
+  ///
+  /// See also:
+  ///
+  ///  * [direction], which specifies the text direction.
   double get end {
     return (direction == TextDirection.ltr) ? right : left;
   }
 
+  @override
   bool operator ==(dynamic other) {
     if (identical(this, other))
       return true;
@@ -710,8 +727,10 @@ class TextBox {
         && typedOther.direction == direction;
   }
 
+  @override
   int get hashCode => hashValues(left, top, right, bottom, direction);
 
+  @override
   String toString() => 'TextBox.fromLTRBD(${left.toStringAsFixed(1)}, ${top.toStringAsFixed(1)}, ${right.toStringAsFixed(1)}, ${bottom.toStringAsFixed(1)}, $direction)';
 }
 
@@ -738,15 +757,45 @@ enum TextAffinity {
 
 /// A visual position in a string of text.
 class TextPosition {
-  const TextPosition({ this.offset, this.affinity: TextAffinity.downstream });
+  /// Creates an object representing a particular position in a string.
+  ///
+  /// The arguments must not be null (so the [offset] argument is required).
+  const TextPosition({
+    this.offset,
+    this.affinity: TextAffinity.downstream,
+  }) : assert(offset != null),
+       assert(affinity != null);
 
-  /// The index of the character just prior to the position.
+  /// The index of the character that immediately follows the position.
+  ///
+  /// For example, given the string `'Hello'`, offset 0 represents the cursor
+  /// being before the `H`, while offset 5 represents the cursor being just
+  /// after the `o`.
   final int offset;
 
   /// If the offset has more than one visual location (e.g., occurs at a line
   /// break), which of the two locations is represented by this position.
+  ///
+  /// For example, if the text `'AB'` had a forced line break between the `A`
+  /// and the `B`, then the downstream affinity at offset 1 represents the
+  /// cursor being just after the `A` on the first line, while the upstream
+  /// affinity at offset 1 represents the cursor being just before the `B` on
+  /// the first line.
   final TextAffinity affinity;
 
+  @override
+  bool operator ==(dynamic other) {
+    if (other.runtimeType != runtimeType)
+      return false;
+    final TextPosition typedOther = other;
+    return typedOther.offset == offset
+        && typedOther.affinity == affinity;
+  }
+
+  @override
+  int get hashCode => hashValues(offset, affinity);
+
+  @override
   String toString() {
     return '$runtimeType(offset: $offset, affinity: $affinity)';
   }
@@ -785,6 +834,7 @@ class ParagraphConstraints {
   /// [Paragraph] with a [ParagraphBuilder].
   final double width;
 
+  @override
   bool operator ==(dynamic other) {
     if (other.runtimeType != runtimeType)
       return false;
@@ -792,8 +842,10 @@ class ParagraphConstraints {
     return typedOther.width == width;
   }
 
+  @override
   int get hashCode => width.hashCode;
 
+  @override
   String toString() => '$runtimeType(width: $width)';
 }
 

travis/analyze.sh

@@ -14,16 +14,18 @@ fi
 
 echo "Analyzing dart:ui library..."
 RESULTS=`dartanalyzer                                                          \
-  --ignore-unrecognized-flags                                                  \
   --supermixin                                                                 \
+  --enable-assert-initializers                                                 \
+  --initializing-formal-access                                                 \
   --enable-strict-call-checks                                                  \
   --enable_type_checks                                                         \
   --strong                                                                     \
+  --no-implicit-dynamic                                                        \
   --package-warnings                                                           \
   --fatal-warnings                                                             \
-  --strong-hints                                                               \
   --fatal-hints                                                                \
   --lints                                                                      \
+  --fatal-lints                                                                \
   out/host_debug_unopt/gen/sky/bindings/dart_ui/ui.dart                        \
   2>&1                                                                         \
   | grep -v "Native functions can only be declared in the SDK and code that is loaded through native extensions" \