Icard/angular-clarity-master(work.../node_modules/pngjs/lib/parser-async.js

166 lines
4.2 KiB
JavaScript

"use strict";
let util = require("util");
let zlib = require("zlib");
let ChunkStream = require("./chunkstream");
let FilterAsync = require("./filter-parse-async");
let Parser = require("./parser");
let bitmapper = require("./bitmapper");
let formatNormaliser = require("./format-normaliser");
let ParserAsync = (module.exports = function (options) {
ChunkStream.call(this);
this._parser = new Parser(options, {
read: this.read.bind(this),
error: this._handleError.bind(this),
metadata: this._handleMetaData.bind(this),
gamma: this.emit.bind(this, "gamma"),
palette: this._handlePalette.bind(this),
transColor: this._handleTransColor.bind(this),
finished: this._finished.bind(this),
inflateData: this._inflateData.bind(this),
simpleTransparency: this._simpleTransparency.bind(this),
headersFinished: this._headersFinished.bind(this),
});
this._options = options;
this.writable = true;
this._parser.start();
});
util.inherits(ParserAsync, ChunkStream);
ParserAsync.prototype._handleError = function (err) {
this.emit("error", err);
this.writable = false;
this.destroy();
if (this._inflate && this._inflate.destroy) {
this._inflate.destroy();
}
if (this._filter) {
this._filter.destroy();
// For backward compatibility with Node 7 and below.
// Suppress errors due to _inflate calling write() even after
// it's destroy()'ed.
this._filter.on("error", function () {});
}
this.errord = true;
};
ParserAsync.prototype._inflateData = function (data) {
if (!this._inflate) {
if (this._bitmapInfo.interlace) {
this._inflate = zlib.createInflate();
this._inflate.on("error", this.emit.bind(this, "error"));
this._filter.on("complete", this._complete.bind(this));
this._inflate.pipe(this._filter);
} else {
let rowSize =
((this._bitmapInfo.width *
this._bitmapInfo.bpp *
this._bitmapInfo.depth +
7) >>
3) +
1;
let imageSize = rowSize * this._bitmapInfo.height;
let chunkSize = Math.max(imageSize, zlib.Z_MIN_CHUNK);
this._inflate = zlib.createInflate({ chunkSize: chunkSize });
let leftToInflate = imageSize;
let emitError = this.emit.bind(this, "error");
this._inflate.on("error", function (err) {
if (!leftToInflate) {
return;
}
emitError(err);
});
this._filter.on("complete", this._complete.bind(this));
let filterWrite = this._filter.write.bind(this._filter);
this._inflate.on("data", function (chunk) {
if (!leftToInflate) {
return;
}
if (chunk.length > leftToInflate) {
chunk = chunk.slice(0, leftToInflate);
}
leftToInflate -= chunk.length;
filterWrite(chunk);
});
this._inflate.on("end", this._filter.end.bind(this._filter));
}
}
this._inflate.write(data);
};
ParserAsync.prototype._handleMetaData = function (metaData) {
this._metaData = metaData;
this._bitmapInfo = Object.create(metaData);
this._filter = new FilterAsync(this._bitmapInfo);
};
ParserAsync.prototype._handleTransColor = function (transColor) {
this._bitmapInfo.transColor = transColor;
};
ParserAsync.prototype._handlePalette = function (palette) {
this._bitmapInfo.palette = palette;
};
ParserAsync.prototype._simpleTransparency = function () {
this._metaData.alpha = true;
};
ParserAsync.prototype._headersFinished = function () {
// Up until this point, we don't know if we have a tRNS chunk (alpha)
// so we can't emit metadata any earlier
this.emit("metadata", this._metaData);
};
ParserAsync.prototype._finished = function () {
if (this.errord) {
return;
}
if (!this._inflate) {
this.emit("error", "No Inflate block");
} else {
// no more data to inflate
this._inflate.end();
}
};
ParserAsync.prototype._complete = function (filteredData) {
if (this.errord) {
return;
}
let normalisedBitmapData;
try {
let bitmapData = bitmapper.dataToBitMap(filteredData, this._bitmapInfo);
normalisedBitmapData = formatNormaliser(bitmapData, this._bitmapInfo);
bitmapData = null;
} catch (ex) {
this._handleError(ex);
return;
}
this.emit("parsed", normalisedBitmapData);
};