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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,43 @@ | ||
| /** | ||
| * AbstractFile is an abstract representation of a file. There are two implementation: | ||
| * 1. RemoteFile - representation of a file on a remote server which can be | ||
| * fetched in chunks, e.g. using a Range request. | ||
| * 2. LoclaStringFile is a representation of a file that was created from input string. | ||
| * Used for testing and small input files. | ||
| * @flow | ||
| */ | ||
| 'use strict'; | ||
|
|
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| //import Q from 'q'; | ||
|
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| class AbstractFile { | ||
| constructor() { | ||
| //how to prevent instantation of this class??? | ||
| //this code doesn't pass npm run flow | ||
| // if (new.target === AbstractFile) { | ||
| // throw new TypeError("Cannot construct AbstractFile instances directly"); | ||
| // } | ||
| } | ||
|
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| getBytes(start: number, length: number):Object {//: Q.Promise<ArrayBuffer> { | ||
| throw new TypeError("Method getBytes is not implemented"); | ||
| } | ||
|
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| // Read the entire file -- not recommended for large files! | ||
| getAll():Object {//: Q.Promise<ArrayBuffer> { | ||
| throw new TypeError("Method getAll is not implemented"); | ||
| } | ||
|
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| // Reads the entire file as a string (not an ArrayBuffer). | ||
| // This does not use the cache. | ||
| getAllString():Object {//: Q.Promise<string> { | ||
| throw new TypeError("Method getAllString is not implemented"); | ||
| } | ||
|
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| // Returns a promise for the number of bytes in the remote file. | ||
| getSize():Object {//: Q.Promise<number> { | ||
| throw new TypeError("Method getSize is not implemented"); | ||
| } | ||
| } | ||
|
|
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| module.exports = AbstractFile; |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,66 @@ | ||
| /** | ||
| * LocalStringFile is a representation of a file that was created from input string. Used for testing and small input files. | ||
| * @flow | ||
| */ | ||
| 'use strict'; | ||
|
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| import Q from 'q'; | ||
| import AbstractFile from './AbstractFile'; | ||
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| class LocalStringFile extends AbstractFile { | ||
| fileLength: number; | ||
| content: string; //content of this "File" | ||
| buffer: ArrayBuffer; | ||
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| constructor(content: string) { | ||
| super(); | ||
| this.fileLength = content.length; | ||
| this.buffer = new ArrayBuffer(content.length); // 2 bytes for each char | ||
| this.content = content; | ||
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| var bufView = new Uint8Array(this.buffer); | ||
| for (var i=0; i < this.fileLength; i++) { | ||
| bufView[i] = content.charCodeAt(i); | ||
| } | ||
| } | ||
|
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| getBytes(start: number, length: number): Q.Promise<ArrayBuffer> { | ||
| if (length < 0) { | ||
| return Q.reject(`Requested <0 bytes (${length})`); | ||
| } | ||
|
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| // If the remote file length is known, clamp the request to fit within it. | ||
| var stop = start + length - 1; | ||
| if (this.fileLength != -1) { | ||
| stop = Math.min(this.fileLength - 1, stop); | ||
| } | ||
|
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| // First check the cache. | ||
| var buf = this.getFromCache(start, stop); | ||
| return Q.when(buf); | ||
| } | ||
|
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| // Read the entire file -- not recommended for large files! | ||
| getAll(): Q.Promise<ArrayBuffer> { | ||
| var buf = this.getFromCache(0, this.fileLength - 1); | ||
| return Q.when(buf); | ||
| } | ||
|
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| // Reads the entire file as a string (not an ArrayBuffer). | ||
| // This does not use the cache. | ||
| getAllString(): Q.Promise<string> { | ||
| return Q.when(this.content); | ||
| } | ||
|
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| // Returns a promise for the number of bytes in the remote file. | ||
| getSize(): Q.Promise<number> { | ||
| return Q.when(this.fileLength); | ||
| } | ||
|
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| getFromCache(start: number, stop: number): ?ArrayBuffer { | ||
| return this.buffer.slice(start, stop + 1); | ||
| } | ||
|
|
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| } | ||
|
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| module.exports = LocalStringFile; |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,113 @@ | ||
| /* @flow */ | ||
| 'use strict'; | ||
|
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| import {expect} from 'chai'; | ||
|
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| import LocalStringFile from '../main/LocalStringFile'; | ||
| import jBinary from 'jbinary'; | ||
|
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| describe('LocalStringFile', () => { | ||
| function bufferToText(buf) { | ||
| return new jBinary(buf).read('string'); | ||
| } | ||
|
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| it('should fetch a subset of a file', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| var promisedData = f.getBytes(4, 5); | ||
|
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| return promisedData.then(buf => { | ||
| expect(buf.byteLength).to.equal(5); | ||
| expect(bufferToText(buf)).to.equal('45678'); | ||
| }); | ||
| }); | ||
|
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| it('should fetch subsets from cache', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getBytes(0, 10).then(buf => { | ||
| expect(buf.byteLength).to.equal(10); | ||
| expect(bufferToText(buf)).to.equal('0123456789'); | ||
| return f.getBytes(4, 5).then(buf => { | ||
| expect(buf.byteLength).to.equal(5); | ||
| expect(bufferToText(buf)).to.equal('45678'); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should fetch entire files', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getAll().then(buf => { | ||
| expect(buf.byteLength).to.equal(11); | ||
| expect(bufferToText(buf)).to.equal('0123456789\n'); | ||
| }); | ||
| }); | ||
|
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| it('should determine file lengths', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getSize().then(size => { | ||
| expect(size).to.equal(11); | ||
| }); | ||
| }); | ||
|
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| it('should get file lengths from full requests', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getAll().then(buf => { | ||
| return f.getSize().then(size => { | ||
| expect(size).to.equal(11); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should get file lengths from range requests', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getBytes(4, 5).then(buf => { | ||
| return f.getSize().then(size => { | ||
| expect(size).to.equal(11); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should cache requests for full files', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| f.getAll().then(buf => { | ||
| expect(buf.byteLength).to.equal(11); | ||
| expect(bufferToText(buf)).to.equal('0123456789\n'); | ||
| return f.getAll().then(buf => { | ||
| expect(buf.byteLength).to.equal(11); | ||
| expect(bufferToText(buf)).to.equal('0123456789\n'); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should serve range requests from cache after getAll', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getAll().then(buf => { | ||
| expect(buf.byteLength).to.equal(11); | ||
| expect(bufferToText(buf)).to.equal('0123456789\n'); | ||
| return f.getBytes(4, 5).then(buf => { | ||
| expect(buf.byteLength).to.equal(5); | ||
| expect(bufferToText(buf)).to.equal('45678'); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should truncate requests past EOF', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| var promisedData = f.getBytes(4, 100); | ||
|
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| return promisedData.then(buf => { | ||
| expect(buf.byteLength).to.equal(7); | ||
| expect(bufferToText(buf)).to.equal('456789\n'); | ||
| return f.getBytes(6, 90).then(buf => { | ||
| expect(buf.byteLength).to.equal(5); | ||
| expect(bufferToText(buf)).to.equal('6789\n'); | ||
| }); | ||
| }); | ||
| }); | ||
|
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| it('should fetch entire files as strings', function() { | ||
| var f = new LocalStringFile('0123456789\n'); | ||
| return f.getAllString().then(txt => { | ||
| expect(txt).to.equal('0123456789\n'); | ||
| }); | ||
| }); | ||
| }); |
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