Source/WebInspectorUI/UserInterface/Controllers/Formatter.js

/*
 * Copyright (C) 2013 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.
 */

WebInspector.Formatter = class Formatter
{
    constructor(codeMirror, builder)
    {
        console.assert(codeMirror);
        console.assert(builder);

        this._codeMirror = codeMirror;
        this._builder = builder;

        this._lastToken = null;
        this._lastContent = "";
    }

    // Public

    format(from, to)
    {
        console.assert(this._builder.originalContent === null);
        if (this._builder.originalContent !== null)
            return;

        var outerMode = this._codeMirror.getMode();
        var content = this._codeMirror.getRange(from, to);
        var state = CodeMirror.copyState(outerMode, this._codeMirror.getTokenAt(from).state);
        this._builder.setOriginalContent(content);

        var lineOffset = 0;
        var lines = content.split("\n");
        for (var i = 0; i < lines.length; ++i) {
            var line = lines[i];
            var startOfNewLine = true;
            var firstTokenOnLine = true;
            var stream = new CodeMirror.StringStream(line);
            while (!stream.eol()) {
                var innerMode = CodeMirror.innerMode(outerMode, state);
                var token = outerMode.token(stream, state);
                var isWhiteSpace = token === null && /^\s*$/.test(stream.current());
                this._handleToken(innerMode.mode, token, state, stream, lineOffset + stream.start, isWhiteSpace, startOfNewLine, firstTokenOnLine);
                stream.start = stream.pos;
                startOfNewLine = false;
                if (firstTokenOnLine && !isWhiteSpace)
                    firstTokenOnLine = false;
            }

            if (firstTokenOnLine)
                this._handleEmptyLine();

            lineOffset += line.length + 1; // +1 for the "\n" removed in split.
            this._handleLineEnding(lineOffset - 1); // -1 for the index of the "\n".
        }

        this._builder.finish();
    }

    // Private

    _handleToken(mode, token, state, stream, originalPosition, isWhiteSpace, startOfNewLine, firstTokenOnLine)
    {
        // String content of the token.
        var content = stream.current();

        // Start of a new line. Insert a newline to be safe if code was not-ASI safe. These are collapsed.
        if (startOfNewLine)
            this._builder.appendNewline();

        // Whitespace. Remove all spaces or collapse to a single space.
        if (isWhiteSpace) {
            this._builder.appendSpace();
            return;
        }

        // Avoid some hooks for content in comments.
        var isComment = token && /\bcomment\b/.test(token);

        if (mode.modifyStateForTokenPre)
            mode.modifyStateForTokenPre(this._lastToken, this._lastContent, token, state, content, isComment);

        // Should we remove the last whitespace?
        if (this._builder.lastTokenWasWhitespace && mode.removeLastWhitespace(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.removeLastWhitespace();

        // Should we remove the last newline?
        if (this._builder.lastTokenWasNewline && mode.removeLastNewline(this._lastToken, this._lastContent, token, state, content, isComment, firstTokenOnLine))
            this._builder.removeLastNewline();

        // Add whitespace after the last token?
        if (!this._builder.lastTokenWasWhitespace && mode.shouldHaveSpaceAfterLastToken(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.appendSpace();

        // Add whitespace before this token?
        if (!this._builder.lastTokenWasWhitespace && mode.shouldHaveSpaceBeforeToken(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.appendSpace();

        // Should we dedent before this token?
        var dedents = mode.dedentsBeforeToken(this._lastToken, this._lastContent, token, state, content, isComment);
        while (dedents-- > 0)
            this._builder.dedent();

        // Should we add a newline before this token?
        if (mode.newlineBeforeToken(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.appendNewline();

        // Should we indent before this token?
        if (mode.indentBeforeToken(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.indent();

        // Append token.
        this._builder.appendToken(content, originalPosition);

        // Let the pretty printer update any state it keeps track of.
        if (mode.modifyStateForTokenPost)
            mode.modifyStateForTokenPost(this._lastToken, this._lastContent, token, state, content, isComment);

        // Should we indent or dedent after this token?
        if (!isComment && mode.indentAfterToken(this._lastToken, this._lastContent, token, state, content, isComment))
            this._builder.indent();

        // Should we add newlines after this token?
        var newlines = mode.newlinesAfterToken(this._lastToken, this._lastContent, token, state, content, isComment);
        if (newlines)
            this._builder.appendMultipleNewlines(newlines);

        // Record this token as the last token.
        this._lastToken = token;
        this._lastContent = content;
    }

    _handleEmptyLine()
    {
        // Preserve original whitespace only lines by adding a newline.
        // However, don't do this if the builder just added multiple newlines.
        if (!(this._builder.lastTokenWasNewline && this._builder.lastNewlineAppendWasMultiple))
            this._builder.appendNewline(true);
    }

    _handleLineEnding(originalNewLinePosition)
    {
        // Record the original line ending.
        this._builder.addOriginalLineEnding(originalNewLinePosition);
    }
};