164 lines
3.7 KiB
JavaScript
Executable file
164 lines
3.7 KiB
JavaScript
Executable file
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/*!
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* Stylus - plugin - url
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* Copyright (c) Automattic <developer.wordpress.com>
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* MIT Licensed
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*/
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/**
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* Module dependencies.
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*/
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var utils = require('../utils')
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, nodes = require('../nodes')
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, Buffer = require('safer-buffer').Buffer
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, fs = require('fs')
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, path = require('path')
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, sax = require('sax');
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/**
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* Initialize a new `Image` with the given `ctx` and `path.
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*
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* @param {Evaluator} ctx
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* @param {String} path
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* @api private
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*/
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var Image = module.exports = function Image(ctx, path) {
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this.ctx = ctx;
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this.path = utils.lookup(path, ctx.paths);
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if (!this.path) throw new Error('failed to locate file ' + path);
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};
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/**
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* Open the image for reading.
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*
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* @api private
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*/
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Image.prototype.open = function(){
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this.fd = fs.openSync(this.path, 'r');
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this.length = fs.fstatSync(this.fd).size;
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this.extname = path.extname(this.path).slice(1);
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};
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/**
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* Close the file.
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*
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* @api private
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*/
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Image.prototype.close = function(){
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if (this.fd) fs.closeSync(this.fd);
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};
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/**
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* Return the type of image, supports:
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*
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* - gif
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* - png
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* - jpeg
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* - svg
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*
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* @return {String}
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* @api private
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*/
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Image.prototype.type = function(){
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var type
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, buf = Buffer.alloc(4);
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fs.readSync(this.fd, buf, 0, 4, 0);
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// GIF
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if (0x47 == buf[0] && 0x49 == buf[1] && 0x46 == buf[2]) type = 'gif';
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// PNG
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else if (0x50 == buf[1] && 0x4E == buf[2] && 0x47 == buf[3]) type = 'png';
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// JPEG
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else if (0xff == buf[0] && 0xd8 == buf[1]) type = 'jpeg';
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// SVG
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else if ('svg' == this.extname) type = this.extname;
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return type;
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};
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/**
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* Return image dimensions `[width, height]`.
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*
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* @return {Array}
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* @api private
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*/
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Image.prototype.size = function(){
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var type = this.type()
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, width
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, height
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, buf
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, offset
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, blockSize
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, parser;
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function uint16(b) { return b[1] << 8 | b[0]; }
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function uint32(b) { return b[0] << 24 | b[1] << 16 | b[2] << 8 | b[3]; }
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// Determine dimensions
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switch (type) {
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case 'jpeg':
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buf = Buffer.alloc(this.length);
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fs.readSync(this.fd, buf, 0, this.length, 0);
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offset = 4;
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blockSize = buf[offset] << 8 | buf[offset + 1];
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while (offset < this.length) {
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offset += blockSize;
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if (offset >= this.length || 0xff != buf[offset]) break;
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// SOF0 or SOF2 (progressive)
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if (0xc0 == buf[offset + 1] || 0xc2 == buf[offset + 1]) {
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height = buf[offset + 5] << 8 | buf[offset + 6];
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width = buf[offset + 7] << 8 | buf[offset + 8];
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} else {
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offset += 2;
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blockSize = buf[offset] << 8 | buf[offset + 1];
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}
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}
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break;
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case 'png':
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buf = Buffer.alloc(8);
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// IHDR chunk width / height uint32_t big-endian
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fs.readSync(this.fd, buf, 0, 8, 16);
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width = uint32(buf);
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height = uint32(buf.slice(4, 8));
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break;
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case 'gif':
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buf = Buffer.alloc(4);
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// width / height uint16_t little-endian
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fs.readSync(this.fd, buf, 0, 4, 6);
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width = uint16(buf);
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height = uint16(buf.slice(2, 4));
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break;
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case 'svg':
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offset = Math.min(this.length, 1024);
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buf = Buffer.alloc(offset);
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fs.readSync(this.fd, buf, 0, offset, 0);
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buf = buf.toString('utf8');
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parser = sax.parser(true);
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parser.onopentag = function(node) {
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if ('svg' == node.name && node.attributes.width && node.attributes.height) {
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width = parseInt(node.attributes.width, 10);
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height = parseInt(node.attributes.height, 10);
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}
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};
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parser.write(buf).close();
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break;
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}
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if ('number' != typeof width) throw new Error('failed to find width of "' + this.path + '"');
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if ('number' != typeof height) throw new Error('failed to find height of "' + this.path + '"');
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return [width, height];
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};
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