DevTools: Implement CSS pretty-printing

Source/devtools/front_end/CSSFormatter.js

Index: Source/devtools/front_end/CSSFormatter.js
diff --git a/Source/devtools/front_end/CSSFormatter.js b/Source/devtools/front_end/CSSFormatter.js
new file mode 100644
index 0000000000000000000000000000000000000000..1c0844daacb13a35289ee716565d823e9d5831c3
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+++ b/Source/devtools/front_end/CSSFormatter.js
@@ -0,0 +1,291 @@
+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @constructor
+ * @param {string} content
+ * @param {!FormatterWorker.CSSFormattedContentBuilder} builder
+ */
+FormatterWorker.CSSFormatter = function(content, builder)
+{
+    this._content = content;
+    this._builder = builder;
+    this._lastLine = -1;
+    this._state = {};
+}
+
+FormatterWorker.CSSFormatter.prototype = {
+    format: function()
+    {
+        this._lineEndings = this._lineEndings(this._content);
+        var tokenize = WebInspector.CodeMirrorUtils.createTokenizer("text/css");
+        var lines = this._content.split("\n");
+
+        for (var i = 0; i < lines.length; ++i) {
+            var line = lines[i];
+            tokenize(line, this._tokenCallback.bind(this, i));
+        }
+        this._builder.flushNewLines(true);
+    },
+
+    /**
+     * @param {string} text
+     */
+    _lineEndings: function(text)
+    {
+        var lineEndings = [];
+        var i = text.indexOf("\n");
+        while (i !== -1) {
+            lineEndings.push(i);
+            i = text.indexOf("\n", i + 1);
+        }
+        lineEndings.push(text.length);
+        return lineEndings;
+    },
+
+    /**
+     * @param {number} startLine
+     * @param {string} token
+     * @param {string} type
+     * @param {number} startColumn
+     */
+    _tokenCallback: function(startLine, token, type, startColumn)
+    {
+        if (startLine !== this._lastLine)
+            this._state.eatWhitespace = true;
+        if (/^css-property/.test(type) && !this._state.inPropertyValue)
+            this._state.seenProperty = true;
+        this._lastLine = startLine;
+        var isWhitespace = /^\s+$/.test(token);
+        if (isWhitespace) {
+            if (!this._state.eatWhitespace)
+                this._builder.addSpace();
+            return;
+        }
+        this._state.eatWhitespace = false;
+        if (token === "\n")
+            return;
+
+        if (token !== "}") {
+            if (this._state.afterClosingBrace)
+                this._builder.addNewLine();
+            this._state.afterClosingBrace = false;
+        }
+        var startPosition = (startLine ? this._lineEndings[startLine - 1] : 0) + startColumn;
+        if (token === "}") {
+            if (this._state.inPropertyValue)
+                this._builder.addNewLine();
+            this._builder.decreaseNestingLevel();
+            this._state.afterClosingBrace = true;
+            this._state.inPropertyValue = false;
+        } else if (token === ":" && !this._state.inPropertyValue && this._state.seenProperty) {
+            this._builder.addToken(token, startPosition, startLine, startColumn);
+            this._builder.addSpace();
+            this._state.eatWhitespace = true;
+            this._state.inPropertyValue = true;
+            this._state.seenProperty = false;
+            return;
+        } else if (token === "{") {
+            this._builder.addSpace();
+            this._builder.addToken(token, startPosition, startLine, startColumn);
+            this._builder.addNewLine();
+            this._builder.increaseNestingLevel();
+            return;
+        }
+
+        this._builder.addToken(token, startPosition, startLine, startColumn);
+
+        if (type === "css-comment" && !this._state.inPropertyValue && !this._state.seenProperty)
+            this._builder.addNewLine();
+        if (token === ";" && this._state.inPropertyValue) {
+            this._state.inPropertyValue = false;
+            this._builder.addNewLine();
+        } else if (token === "}") {
+            this._builder.addNewLine();
+        }
+    }
+}
+
+/**
+ * @constructor
+ * @param {string} content
+ * @param {{original: Array.<number>, formatted: Array.<number>}} mapping
+ * @param {number} originalOffset
+ * @param {number} formattedOffset
+ * @param {string} indentString
+ */
+FormatterWorker.CSSFormattedContentBuilder = function(content, mapping, originalOffset, formattedOffset, indentString)
+{
+    this._originalContent = content;
+    this._originalOffset = originalOffset;
+    this._lastOriginalPosition = 0;
+
+    this._formattedContent = [];
+    this._formattedContentLength = 0;
+    this._formattedOffset = formattedOffset;
+    this._lastFormattedPosition = 0;
+
+    this._mapping = mapping;
+
+    this._lineNumber = 0;
+    this._nestingLevel = 0;
+    this._needNewLines = 0;
+    this._atLineStart = true;
+    this._indentString = indentString;
+    this._cachedIndents = {};
+}
+
+FormatterWorker.CSSFormattedContentBuilder.prototype = {
+    /**
+     * @param {string} token
+     * @param {number} startPosition
+     * @param {number} startLine
+     * @param {number} startColumn
+     */
+    addToken: function(token, startPosition, startLine, startColumn)
+    {
+        if ((this._isWhitespaceRun || this._atLineStart) && /^\s+$/.test(token))
+            return;
+
+        if (this._isWhitespaceRun && this._lineNumber === startLine && !this._needNewLines)
+            this._addText(" ");
+
+        this._isWhitespaceRun = false;
+        this._atLineStart = false;
+
+        while (this._lineNumber < startLine) {
+            this._addText("\n");
+            this._addIndent();
+            this._needNewLines = 0;
+            this._lineNumber += 1;
+            this._atLineStart = true;
+        }
+
+        if (this._needNewLines) {
+            this.flushNewLines();
+            this._addIndent();
+            this._atLineStart = true;
+        }
+
+        this._addMappingIfNeeded(startPosition);
+        this._addText(token);
+        this._lineNumber = startLine;
+    },
+
+    addSpace: function()
+    {
+        if (this._isWhitespaceRun)
+            return;
+        this._isWhitespaceRun = true;
+    },
+
+    addNewLine: function()
+    {
+        ++this._needNewLines;
+    },
+
+    /**
+     * @param {boolean=} atLeastOne
+     */
+    flushNewLines: function(atLeastOne)
+    {
+        var newLineCount = atLeastOne && !this._needNewLines ? 1 : this._needNewLines;
+        if (newLineCount)
+            this._isWhitespaceRun = false;
+        for (var i = 0; i < newLineCount; ++i)
+            this._addText("\n");
+        this._needNewLines = 0;
+    },
+
+    increaseNestingLevel: function()
+    {
+        this._nestingLevel += 1;
+    },
+
+    /**
+     * @param {boolean=} addNewline
+     */
+    decreaseNestingLevel: function(addNewline)
+    {
+        if (this._nestingLevel)
+            this._nestingLevel -= 1;
+        if (addNewline)
+            this.addNewLine();
+    },
+
+    /**
+     * @return {string}
+     */
+    content: function()
+    {
+        return this._formattedContent.join("");
+    },
+
+    _addIndent: function()
+    {
+        if (this._cachedIndents[this._nestingLevel]) {
+            this._addText(this._cachedIndents[this._nestingLevel]);
+            return;
+        }
+
+        var fullIndent = "";
+        for (var i = 0; i < this._nestingLevel; ++i)
+            fullIndent += this._indentString;
+        this._addText(fullIndent);
+
+        // Cache a maximum of 20 nesting level indents.
+        if (this._nestingLevel <= 20)
+            this._cachedIndents[this._nestingLevel] = fullIndent;
+    },
+
+    /**
+     * @param {string} text
+     */
+    _addText: function(text)
+    {
+        if (!text)
+            return;
+        this._formattedContent.push(text);
+        this._formattedContentLength += text.length;
+    },
+
+    /**
+     * @param {number} originalPosition
+     */
+    _addMappingIfNeeded: function(originalPosition)
+    {
+        if (originalPosition - this._lastOriginalPosition === this._formattedContentLength - this._lastFormattedPosition)
+            return;
+        this._mapping.original.push(this._originalOffset + originalPosition);
+        this._lastOriginalPosition = originalPosition;
+        this._mapping.formatted.push(this._formattedOffset + this._formattedContentLength);
+        this._lastFormattedPosition = this._formattedContentLength;
+    }
+}