DevTools: remove illusionary caching from String.prototype.lineEndings

third_party/WebKit/Source/devtools/front_end/common/Text.js

Index: third_party/WebKit/Source/devtools/front_end/common/Text.js
diff --git a/third_party/WebKit/Source/devtools/front_end/common/Text.js b/third_party/WebKit/Source/devtools/front_end/common/Text.js
new file mode 100644
index 0000000000000000000000000000000000000000..4e02e37d912ecfe86b03dc0f7d4bf69008564004
--- /dev/null
+++ b/third_party/WebKit/Source/devtools/front_end/common/Text.js
@@ -0,0 +1,97 @@
+// Copyright 2016 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.
+
+/**
+ * @constructor
+ * @param {string} value
+ */
+WebInspector.Text = function(value)
+{
+    this._value = value;
+}
+
+WebInspector.Text.prototype = {
+    /**
+     * @return {!Array<number>}
+     */
+    lineEndings: function()
+    {
+        if (!this._lineEndings)
+            this._lineEndings = this._value.computeLineEndings();
+        return this._lineEndings;
+    },
+
+    /**
+     * @return {string}
+     */
+    value: function()
+    {
+        return this._value;
+    },
+
+    /**
+     * @return {number}
+     */
+    lineCount: function()
+    {
+        var lineEndings = this.lineEndings();
+        return lineEndings.length;
+    },
+
+    /**
+     * @param {number} lineNumber
+     * @param {number} columNumber
+     * @return {number}
+     */
+    offsetFromPosition: function(lineNumber, columNumber)
+    {
+        return (lineNumber ? this.lineEndings()[lineNumber - 1] + 1 : 0) + columNumber;
+    },
+
+    /**
+     * @return {string}
+     */
+    lineAt: function(lineNumber)
+    {
+        var lineEndings = this.lineEndings();
+        var lineStart = lineNumber > 0 ? lineEndings[lineNumber - 1] + 1 : 0;
+        var lineEnd = lineEndings[lineNumber];
+        var lineContent = this._value.substring(lineStart, lineEnd);
+        if (lineContent.length > 0 && lineContent.charAt(lineContent.length - 1) === "\r")
+            lineContent = lineContent.substring(0, lineContent.length - 1);
+        return lineContent;
+    },
+
+    /**
+     * @param {!WebInspector.TextRange} range
+     * @return {!WebInspector.SourceRange}
+     */
+    toSourceRange: function(range)
+    {
+        var start = this.offsetFromPosition(range.startLine, range.startColumn);
+        var end = this.offsetFromPosition(range.endLine, range.endColumn);
+        return new WebInspector.SourceRange(start, end - start);
+    },
+
+    /**
+     * @param {!WebInspector.TextRange} range
+     * @param {string} replacement
+     * @return {string}
+     */
+    replaceRange: function(range, replacement)
+    {
+        var sourceRange = this.toSourceRange(range);
+        return this._value.substring(0, sourceRange.offset) + replacement + this._value.substring(sourceRange.offset + sourceRange.length);
+    },
+
+    /**
+     * @param {!WebInspector.TextRange} range
+     * @return {string}
+     */
+    extract: function(range)
+    {
+        var sourceRange = this.toSourceRange(range);
+        return this._value.substr(sourceRange.offset, sourceRange.length);
+    },
+}