Files
react/vendor/fbtransform/lib/utils.js
T
Paul O’Shannessy 75897c2dcd Initial public release
2013-05-29 12:54:02 -07:00

333 lines
8.9 KiB
JavaScript

/**
* Copyright 2013 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*global exports:true*/
/**
* State represents the given parser state. It has a local and global parts.
* Global contains parser position, source, etc. Local contains scope based
* properties, like current class name. State should contain all the info
* required for transformation. It's the only mandatory object that is being
* passed to every function in transform chain.
*
* @param {String} source
* @param {Object} transformOptions
* @return {Object}
*/
function createState(source, transformOptions) {
return {
/**
* Name of the super class variable
* @type {String}
*/
superVar: '',
/**
* Name of the enclosing class scope
* @type {String}
*/
scopeName: '',
/**
* Global state (not affected by updateState)
* @type {Object}
*/
g: {
/**
* A set of general options that transformations can consider while doing
* a transformation:
*
* - minify
* Specifies that transformation steps should do their best to minify
* the output source when possible. This is useful for places where
* minification optimizations are possible with higher-level context
* info than what jsxmin can provide.
*
* For example, the ES6 class transform will minify munged private
* variables if this flag is set.
*/
opts: transformOptions,
/**
* Current position in the source code
* @type {Number}
*/
position: 0,
/**
* Buffer containing the result
* @type {String}
*/
buffer: '',
/**
* Indentation offset (only negative offset is supported now)
* @type {Number}
*/
indentBy: 0,
/**
* Source that is being transformed
* @type {String}
*/
source: source,
/**
* Cached parsed docblock (see getDocblock)
* @type {object}
*/
docblock: null,
/**
* Whether the thing was used
* @type {Boolean}
*/
tagNamespaceUsed: false,
/**
* If using bolt xjs transformation
* @type {Boolean}
*/
isBolt: undefined,
/**
* Whether to record source map (expensive) or not
* @type {SourceMapGenerator|null}
*/
sourceMap: null,
/**
* Filename of the file being processed. Will be returned as a source
* attribute in the source map
*/
sourceMapFilename: 'source.js',
/**
* Only when source map is used: last line in the source for which
* source map was generated
* @type {Number}
*/
sourceLine: 1,
/**
* Only when source map is used: last line in the buffer for which
* source map was generated
* @type {Number}
*/
bufferLine: 1,
/**
* The top-level Program AST for the original file.
*/
originalProgramAST: null,
sourceColumn: 0,
bufferColumn: 0
}
};
}
/**
* Updates a copy of a given state with "update" and returns an updated state.
*
* @param {Object} state
* @param {Object} update
* @return {Object}
*/
function updateState(state, update) {
return {
g: state.g,
superVar: update.superVar || state.superVar,
scopeName: update.scopeName || state.scopeName
};
}
/**
* Given a state fill the resulting buffer from the original source up to
* the end
* @param {Number} end
* @param {Object} state
* @param {Function?} contentTransformer Optional callback to transform newly
* added content.
*/
function catchup(end, state, contentTransformer) {
if (end < state.g.position) {
// cannot move backwards
return;
}
var source = state.g.source.substring(state.g.position, end);
var transformed = updateIndent(source, state);
if (state.g.sourceMap && transformed) {
// record where we are
state.g.sourceMap.addMapping({
generated: { line: state.g.bufferLine, column: state.g.bufferColumn },
original: { line: state.g.sourceLine, column: state.g.sourceColumn },
source: state.g.sourceMapFilename
});
// record line breaks in transformed source
var sourceLines = source.split('\n');
var transformedLines = transformed.split('\n');
// Add line break mappings between last known mapping and the end of the
// added piece. So for the code piece
// (foo, bar);
// > var x = 2;
// > var b = 3;
// var c =
// only add lines marked with ">": 2, 3.
for (var i = 1; i < sourceLines.length - 1; i++) {
state.g.sourceMap.addMapping({
generated: { line: state.g.bufferLine, column: 0 },
original: { line: state.g.sourceLine, column: 0 },
source: state.g.sourceMapFilename
});
state.g.sourceLine++;
state.g.bufferLine++;
}
// offset for the last piece
if (sourceLines.length > 1) {
state.g.sourceLine++;
state.g.bufferLine++;
state.g.sourceColumn = 0;
state.g.bufferColumn = 0;
}
state.g.sourceColumn += sourceLines[sourceLines.length - 1].length;
state.g.bufferColumn +=
transformedLines[transformedLines.length - 1].length;
}
state.g.buffer +=
contentTransformer ? contentTransformer(transformed) : transformed;
state.g.position = end;
}
/**
* Applies `catchup` but passing in a function that removes any non-whitespace
* characters.
*/
var re = /(\S)/g;
function stripNonWhite(value) {
return value.replace(re, function() {
return '';
});
}
/**
* Catches up as `catchup` but turns each non-white character into a space.
*/
function catchupWhiteSpace(end, state) {
catchup(end, state, stripNonWhite);
}
/**
* Same as catchup but does not touch the buffer
* @param {Number} end
* @param {Object} state
*/
function move(end, state) {
// move the internal cursors
if (state.g.sourceMap) {
if (end < state.g.position) {
state.g.position = 0;
state.g.sourceLine = 1;
state.g.sourceColumn = 0;
}
var source = state.g.source.substring(state.g.position, end);
var sourceLines = source.split('\n');
if (sourceLines.length > 1) {
state.g.sourceLine += sourceLines.length - 1;
state.g.sourceColumn = 0;
}
state.g.sourceColumn += sourceLines[sourceLines.length - 1].length;
}
state.g.position = end;
}
/**
* Appends a string of text to the buffer
* @param {String} string
* @param {Object} state
*/
function append(string, state) {
if (state.g.sourceMap && string) {
state.g.sourceMap.addMapping({
generated: { line: state.g.bufferLine, column: state.g.bufferColumn },
original: { line: state.g.sourceLine, column: state.g.sourceColumn },
source: state.g.sourceMapFilename
});
var transformedLines = string.split('\n');
if (transformedLines.length > 1) {
state.g.bufferLine += transformedLines.length - 1;
state.g.bufferColumn = 0;
}
state.g.bufferColumn +=
transformedLines[transformedLines.length - 1].length;
}
state.g.buffer += string;
}
/**
* Update indent using state.indentBy property. Indent is measured in
* double spaces. Updates a single line only.
*
* @param {String} str
* @param {Object} state
* @return {String}
*/
function updateIndent(str, state) {
for (var i = 0; i < -state.g.indentBy; i++) {
str = str.replace(/(^|\n)( {2}|\t)/g, '$1');
}
return str;
}
/**
* Calculates indent from the beginning of the line until "start" or the first
* character before start.
* @example
* " foo.bar()"
* ^
* start
* indent will be 2
*
* @param {Number} start
* @param {Object} state
* @return {Number}
*/
function indentBefore(start, state) {
var end = start;
start = start - 1;
while (start > 0 && state.g.source[start] != '\n') {
if (!state.g.source[start].match(/[ \t]/)) {
end = start;
}
start--;
}
return state.g.source.substring(start + 1, end);
}
function getDocblock(state) {
if (!state.g.docblock) {
var docblock = require('./docblock');
state.g.docblock =
docblock.parseAsObject(docblock.extract(state.g.source));
}
return state.g.docblock;
}
exports.catchup = catchup;
exports.catchupWhiteSpace = catchupWhiteSpace;
exports.append = append;
exports.move = move;
exports.updateIndent = updateIndent;
exports.indentBefore = indentBefore;
exports.updateState = updateState;
exports.createState = createState;
exports.getDocblock = getDocblock;