//
// Copyright (c) Microsoft and contributors. All rights reserved.
//
// 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.
//
var Constants = require('./../../../common/util/constants');
var EventEmitter = require('events').EventEmitter;
var BlobUtilities = require('./../blobutilities');
/**
* BlockBlob block range stream
*/
function BlockRangeStream(blobServiceClient, container, blob, options) {
console.log('[XXXXXXXXXXXXXX]');
this.blobServiceClient = blobServiceClient;
this.container = container;
this.blob = blob;
this._emitter = new EventEmitter();
this._paused = false;
this._emittedAll = false;
this._emittedRangeType = null;
this._emittedRangeIndex = null;
this._offset = 0;
this._rangelist = [];
this._isEmitting = false;
Iif (options.rangeStart) {
this._startOffset = options.rangeStart;
} else {
this._startOffset = 0;
}
Iif (options.rangeEnd) {
this._endOffset = options.rangeEnd;
} else {
this._endOffset = Number.MAX_VALUE;
}
}
/**
* Add event listener
*/
BlockRangeStream.prototype.on = function (event, listener) {
this._emitter.on(event, listener);
};
/**
* Get block list
*/
BlockRangeStream.prototype.list = function (options) {
Iif (!options) {
options = {};
}
Eif (!options.bloblistType) {
options.bloblistType = BlobUtilities.BlockListFilter.ALL;
}
var self = this;
this.blobServiceClient.listBlocks(this.container, this.blob, options.bloblistType, options, function (error, blocklist, response) {
Iif (error) throw error;
var totalSize = parseInt(response.headers[Constants.HeaderConstants.BLOB_CONTENT_LENGTH], 10);
Iif (!blocklist.CommittedBlocks) {
//Convert single block blob to block blob range
var name = 'NODESDK_BLOCKBLOB_RANGESTREAM';
blocklist.CommittedBlocks = [{ Name : name, Size : totalSize }];
}
self._rangelist = blocklist;
self._emitBlockList();
self = blocklist = null;
});
};
/**
* Emit block ranges
*/
BlockRangeStream.prototype._emitBlockList = function () {
if (this._paused || this._emittedAll || this._isEmitting) return;
var self = this;
this._getTypeList(function () {
self._rangelist = null;
self._emittedAll = true;
self._emitter.emit('end');
});
};
/**
* Get the block type list
*/
BlockRangeStream.prototype._getTypeList = function (callback) {
this._isEmitting = true;
try {
var typeStart = false;
for (var blockType in this._rangelist) {
Eif (this._rangelist.hasOwnProperty(blockType)) {
Eif (this._emittedRangeType === null || typeStart || this._emittedRangeType == blockType) {
this._emittedRangeType = blockType;
typeStart = true;
} else if (this._emittedRangeType !== blockType) {
continue;
}
Iif (this._paused) {
return;
}
this._emitBlockRange (blockType, callback);
}
}
} finally {
this._isEmitting = false;
}
};
/**
* Get the block list
*/
BlockRangeStream.prototype._emitBlockRange = function (blockType, callback) {
var blockList = this._rangelist[blockType];
var indexStart = false;
for (var blockIndex = 0; blockIndex < blockList.length; blockIndex++) {
Eif (this._emittedRangeIndex === null || indexStart || this._emittedRangeIndex === blockIndex) {
this._emittedRangeIndex = blockIndex;
indexStart = true;
} else if (this._emittedRangeIndex !== blockIndex) {
continue;
}
Iif (this._paused) {
return;
}
var range = blockList[blockIndex];
// follow the same naming convention of page ranges and json
range.name = range.Name;
range.type = blockType;
range.start = this._offset;
this._offset += parseInt(range.Size, 10);
range.end = this._offset - 1;
delete range.Name;
delete range.Size;
Iif (range.start > this._endOffset) {
break;
} else Iif (range.end < this._startOffset) {
continue;
} else {
range.start = Math.max(range.start, this._startOffset);
range.end = Math.min(range.end, this._endOffset);
range.size = range.end - range.start + 1;
range.dataSize = range.size;
this._emitter.emit('range', range);
}
}
// remove the used range and avoid memory leak
this._rangelist[blockType] = null;
callback();
};
/**
* Pause the stream
*/
BlockRangeStream.prototype.pause = function () {
this._paused = true;
};
/**
* Resume the stream
*/
BlockRangeStream.prototype.resume = function () {
this._paused = false;
Eif (!this._isEmitting) {
this._emitBlockList();
}
};
module.exports = BlockRangeStream;
|