Merge pull request #2165 from Hixie/hashCodes

Provide an API for hashCode getters.

sky/engine/core/core.gni

@@ -258,9 +258,10 @@ core_idl_files = get_path_info([
                                "abspath")
 
 core_dart_files = get_path_info([
+                                  "dart/hash_codes.dart",
                                   "dart/hooks.dart",
-                                  "dart/natives.dart",
                                   "dart/lerp.dart",
+                                  "dart/natives.dart",
                                   "dart/painting.dart",
                                   "dart/text.dart",
                                   "dart/window.dart",
@@ -276,9 +277,9 @@ core_dart_files = get_path_info([
                                   "painting/Paint.dart",
                                   "painting/PaintingStyle.dart",
                                   "painting/Point.dart",
-                                  "painting/Rect.dart",
                                   "painting/RRect.dart",
                                   "painting/RSTransform.dart",
+                                  "painting/Rect.dart",
                                   "painting/Size.dart",
                                   "painting/TransferMode.dart",
                                   "painting/VertexMode.dart",

sky/engine/core/dart/hash_codes.dart

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+part of dart_ui;
+
+class _HashEnd { const _HashEnd(); }
+const _HashEnd _hashEnd = const _HashEnd();
+
+/// Combine up to twenty values' hashCodes into one value.
+///
+/// If you only need to handle one value's hashCode, then just refer to its
+/// [hashCode] getter directly.
+///
+/// If you need to combine an arbitrary number of values from a List or other
+/// Iterable, use [hashList]. The output of hashList can be used as one of the
+/// arguments to this function.
+///
+/// For example:
+///
+///   int hashCode => hashValues(foo, bar, hashList(quux), baz);
+int hashValues(
+  Object arg01,            Object arg02,          [ Object arg03 = _hashEnd,
+  Object arg04 = _hashEnd, Object arg05 = _hashEnd, Object arg06 = _hashEnd,
+  Object arg07 = _hashEnd, Object arg08 = _hashEnd, Object arg09 = _hashEnd,
+  Object arg10 = _hashEnd, Object arg11 = _hashEnd, Object arg12 = _hashEnd,
+  Object arg13 = _hashEnd, Object arg14 = _hashEnd, Object arg15 = _hashEnd,
+  Object arg16 = _hashEnd, Object arg17 = _hashEnd, Object arg18 = _hashEnd,
+  Object arg19 = _hashEnd, Object arg20 = _hashEnd ]) {
+  int result = 373;
+  assert(arg01 is! Iterable);
+  result = 37 * result + arg01.hashCode;
+  assert(arg02 is! Iterable);
+  result = 37 * result + arg02.hashCode;
+  if (arg03 != _hashEnd) {
+    assert(arg03 is! Iterable);
+    result = 37 * result + arg03.hashCode;
+    if (arg04 != _hashEnd) {
+      assert(arg04 is! Iterable);
+      result = 37 * result + arg04.hashCode;
+      if (arg05 != _hashEnd) {
+        assert(arg05 is! Iterable);
+        result = 37 * result + arg05.hashCode;
+        if (arg06 != _hashEnd) {
+          assert(arg06 is! Iterable);
+          result = 37 * result + arg06.hashCode;
+          if (arg07 != _hashEnd) {
+            assert(arg07 is! Iterable);
+            result = 37 * result + arg07.hashCode;
+            if (arg08 != _hashEnd) {
+              assert(arg08 is! Iterable);
+              result = 37 * result + arg08.hashCode;
+              if (arg09 != _hashEnd) {
+                assert(arg09 is! Iterable);
+                result = 37 * result + arg09.hashCode;
+                if (arg10 != _hashEnd) {
+                  assert(arg10 is! Iterable);
+                  result = 37 * result + arg10.hashCode;
+                  if (arg11 != _hashEnd) {
+                    assert(arg11 is! Iterable);
+                    result = 37 * result + arg11.hashCode;
+                    if (arg12 != _hashEnd) {
+                      assert(arg12 is! Iterable);
+                      result = 37 * result + arg12.hashCode;
+                      if (arg13 != _hashEnd) {
+                        assert(arg13 is! Iterable);
+                        result = 37 * result + arg13.hashCode;
+                        if (arg14 != _hashEnd) {
+                          assert(arg14 is! Iterable);
+                          result = 37 * result + arg14.hashCode;
+                          if (arg15 != _hashEnd) {
+                            assert(arg15 is! Iterable);
+                            result = 37 * result + arg15.hashCode;
+                            if (arg16 != _hashEnd) {
+                              assert(arg16 is! Iterable);
+                              result = 37 * result + arg16.hashCode;
+                              if (arg17 != _hashEnd) {
+                                assert(arg17 is! Iterable);
+                                result = 37 * result + arg17.hashCode;
+                                if (arg18 != _hashEnd) {
+                                  assert(arg18 is! Iterable);
+                                  result = 37 * result + arg18.hashCode;
+                                  if (arg19 != _hashEnd) {
+                                    assert(arg19 is! Iterable);
+                                    result = 37 * result + arg19.hashCode;
+                                    if (arg20 != _hashEnd) {
+                                      assert(arg20 is! Iterable);
+                                      result = 37 * result + arg20.hashCode;
+                                      // I can see my house from here!
+                                    }
+                                  }
+                                }
+                              }
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  return result;
+}
+
+/// Combine the hashCodes of an arbitrary number of values from an Iterable into
+/// one value. This function will return the same value if given "null" as if
+/// given an empty list.
+int hashList(Iterable<Object> args) {
+  int result = 373;
+  if (args != null) {
+    for (Object arg in args) {
+      assert(arg is! Iterable);
+      result = 37 * result + arg.hashCode;
+    }
+  }
+  return result;
+}

sky/engine/core/painting/OffsetBase.dart

@@ -25,10 +25,5 @@ abstract class OffsetBase {
            _dy == typedOther._dy;
   }
 
-  int get hashCode {
-    int result = 373;
-    result = 37 * result + _dx.hashCode;
-    result = 37 * result + _dy.hashCode;
-    return result;
-  }
+  int get hashCode => hashValues(_dx, _dy);
 }

sky/engine/core/painting/Point.dart

@@ -47,12 +47,7 @@ class Point {
            y == typedOther.y;
   }
 
-  int get hashCode {
-    int result = 373;
-    result = 37 * result + x.hashCode;
-    result = 37 * result + y.hashCode;
-    return result;
-  }
+  int get hashCode => hashValues(x, y);
 
   String toString() => "Point(${x.toStringAsFixed(1)}, ${y.toStringAsFixed(1)})";
 }

sky/engine/core/painting/RRect.dart

@@ -229,7 +229,7 @@ class RRect {
     return true;
   }
 
-  int get hashCode => _value.fold(373, (value, item) => (37 * value + item.hashCode));
+  int get hashCode => hashList(_value);
 
   String toString() => "RRect.fromLTRBXY(${left.toStringAsFixed(1)}, ${top.toStringAsFixed(1)}, ${right.toStringAsFixed(1)}, ${bottom.toStringAsFixed(1)}, ${radiusX.toStringAsFixed(1)}, ${radiusY.toStringAsFixed(1)})";
 }

sky/engine/core/painting/Rect.dart

@@ -143,7 +143,7 @@ class Rect {
     return true;
   }
 
-  int get hashCode => _value.fold(373, (value, item) => (37 * value + item.hashCode));
+  int get hashCode => hashList(_value);
 
   String toString() => "Rect.fromLTRB(${left.toStringAsFixed(1)}, ${top.toStringAsFixed(1)}, ${right.toStringAsFixed(1)}, ${bottom.toStringAsFixed(1)})";
 }