162 lines
4 KiB
JavaScript
162 lines
4 KiB
JavaScript
"use strict";
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/** @interface */
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function FileStorageInterface() {}
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/**
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* Read a portion of a file.
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* @param {string} sha256sum
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* @param {number} offset
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* @param {number} count
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* @return {!Promise<Uint8Array>} null if file does not exist.
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*/
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FileStorageInterface.prototype.read = function(sha256sum, offset, count) {};
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/**
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* Add a read-only file to the filestorage.
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* @param {string} sha256sum
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* @param {!Uint8Array} data
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* @return {!Promise}
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*/
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FileStorageInterface.prototype.cache = function(sha256sum, data) {};
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/**
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* Call this when the file won't be used soon, e.g. when a file closes or when this immutable
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* version is already out of date. It is used to help prevent accumulation of unused files in
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* memory in the long run for some FileStorage mediums.
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*/
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FileStorageInterface.prototype.uncache = function(sha256sum) {};
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/**
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* @constructor
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* @implements {FileStorageInterface}
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*/
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function MemoryFileStorage()
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{
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/**
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* From sha256sum to file data.
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* @type {Map<string,Uint8Array>}
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*/
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this.filedata = new Map();
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}
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/**
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* @param {string} sha256sum
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* @param {number} offset
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* @param {number} count
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* @return {!Promise<Uint8Array>} null if file does not exist.
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*/
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MemoryFileStorage.prototype.read = async function(sha256sum, offset, count)
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{
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dbg_assert(sha256sum, "MemoryFileStorage read: sha256sum should be a non-empty string");
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const data = this.filedata.get(sha256sum);
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if(!data)
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{
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return null;
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}
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return data.subarray(offset, offset + count);
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};
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/**
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* @param {string} sha256sum
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* @param {!Uint8Array} data
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*/
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MemoryFileStorage.prototype.cache = async function(sha256sum, data)
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{
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dbg_assert(sha256sum, "MemoryFileStorage cache: sha256sum should be a non-empty string");
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this.filedata.set(sha256sum, data);
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};
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/**
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* @param {string} sha256sum
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*/
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MemoryFileStorage.prototype.uncache = function(sha256sum)
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{
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this.filedata.delete(sha256sum);
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};
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/**
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* @constructor
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* @implements {FileStorageInterface}
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* @param {FileStorageInterface} file_storage
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* @param {string} baseurl
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*/
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function ServerFileStorageWrapper(file_storage, baseurl)
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{
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dbg_assert(baseurl, "ServerMemoryFileStorage: baseurl should not be empty");
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this.storage = file_storage;
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this.baseurl = baseurl;
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}
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/**
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* @param {string} sha256sum
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* @return {!Promise<Uint8Array>}
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*/
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ServerFileStorageWrapper.prototype.load_from_server = function(sha256sum)
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{
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return new Promise((resolve, reject) =>
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{
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v86util.load_file(this.baseurl + sha256sum, { done: async buffer =>
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{
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const data = new Uint8Array(buffer);
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await this.cache(sha256sum, data);
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resolve(data);
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}});
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});
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};
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/**
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* @param {string} sha256sum
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* @param {number} offset
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* @param {number} count
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* @return {!Promise<Uint8Array>}
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*/
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ServerFileStorageWrapper.prototype.read = async function(sha256sum, offset, count)
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{
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const data = await this.storage.read(sha256sum, offset, count);
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if(!data)
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{
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const full_file = await this.load_from_server(sha256sum);
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return full_file.subarray(offset, offset + count);
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}
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return data;
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};
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/**
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* @param {string} sha256sum
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* @param {!Uint8Array} data
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*/
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ServerFileStorageWrapper.prototype.cache = async function(sha256sum, data)
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{
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return await this.storage.cache(sha256sum, data);
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};
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/**
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* @param {string} sha256sum
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*/
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ServerFileStorageWrapper.prototype.uncache = function(sha256sum)
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{
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this.storage.uncache(sha256sum);
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};
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// Closure Compiler's way of exporting
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if(typeof window !== "undefined")
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{
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window["MemoryFileStorage"] = MemoryFileStorage;
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window["ServerFileStorageWrapper"] = ServerFileStorageWrapper;
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}
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else if(typeof module !== "undefined" && typeof module.exports !== "undefined")
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{
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module.exports["MemoryFileStorage"] = MemoryFileStorage;
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module.exports["ServerFileStorageWrapper"] = ServerFileStorageWrapper;
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}
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else if(typeof importScripts === "function")
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{
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// web worker
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self["MemoryFileStorage"] = MemoryFileStorage;
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self["ServerFileStorageWrapper"] = ServerFileStorageWrapper;
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}
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