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| 1 | +'use strict'; |
| 2 | + |
| 3 | +const { Buffer } = require('buffer'); |
| 4 | +const { FSReqWrap, close, read } = process.binding('fs'); |
| 5 | + |
| 6 | +const kReadFileBufferLength = 8 * 1024; |
| 7 | + |
| 8 | +function readFileAfterRead(err, bytesRead) { |
| 9 | + const context = this.context; |
| 10 | + |
| 11 | + if (err) |
| 12 | + return context.close(err); |
| 13 | + |
| 14 | + if (bytesRead === 0) |
| 15 | + return context.close(); |
| 16 | + |
| 17 | + context.pos += bytesRead; |
| 18 | + |
| 19 | + if (context.size !== 0) { |
| 20 | + if (context.pos === context.size) |
| 21 | + context.close(); |
| 22 | + else |
| 23 | + context.read(); |
| 24 | + } else { |
| 25 | + // unknown size, just read until we don't get bytes. |
| 26 | + context.buffers.push(context.buffer.slice(0, bytesRead)); |
| 27 | + context.read(); |
| 28 | + } |
| 29 | +} |
| 30 | + |
| 31 | +function readFileAfterClose(err) { |
| 32 | + const context = this.context; |
| 33 | + const callback = context.callback; |
| 34 | + let buffer = null; |
| 35 | + |
| 36 | + if (context.err || err) |
| 37 | + return callback(context.err || err); |
| 38 | + |
| 39 | + try { |
| 40 | + if (context.size === 0) |
| 41 | + buffer = Buffer.concat(context.buffers, context.pos); |
| 42 | + else if (context.pos < context.size) |
| 43 | + buffer = context.buffer.slice(0, context.pos); |
| 44 | + else |
| 45 | + buffer = context.buffer; |
| 46 | + |
| 47 | + if (context.encoding) |
| 48 | + buffer = buffer.toString(context.encoding); |
| 49 | + } catch (err) { |
| 50 | + return callback(err); |
| 51 | + } |
| 52 | + |
| 53 | + callback(null, buffer); |
| 54 | +} |
| 55 | + |
| 56 | +class ReadFileContext { |
| 57 | + constructor(callback, encoding) { |
| 58 | + this.fd = undefined; |
| 59 | + this.isUserFd = undefined; |
| 60 | + this.size = undefined; |
| 61 | + this.callback = callback; |
| 62 | + this.buffers = null; |
| 63 | + this.buffer = null; |
| 64 | + this.pos = 0; |
| 65 | + this.encoding = encoding; |
| 66 | + this.err = null; |
| 67 | + } |
| 68 | + |
| 69 | + read() { |
| 70 | + let buffer; |
| 71 | + let offset; |
| 72 | + let length; |
| 73 | + |
| 74 | + if (this.size === 0) { |
| 75 | + buffer = this.buffer = Buffer.allocUnsafeSlow(kReadFileBufferLength); |
| 76 | + offset = 0; |
| 77 | + length = kReadFileBufferLength; |
| 78 | + } else { |
| 79 | + buffer = this.buffer; |
| 80 | + offset = this.pos; |
| 81 | + length = Math.min(kReadFileBufferLength, this.size - this.pos); |
| 82 | + } |
| 83 | + |
| 84 | + const req = new FSReqWrap(); |
| 85 | + req.oncomplete = readFileAfterRead; |
| 86 | + req.context = this; |
| 87 | + |
| 88 | + read(this.fd, buffer, offset, length, -1, req); |
| 89 | + } |
| 90 | + |
| 91 | + close(err) { |
| 92 | + const req = new FSReqWrap(); |
| 93 | + req.oncomplete = readFileAfterClose; |
| 94 | + req.context = this; |
| 95 | + this.err = err; |
| 96 | + |
| 97 | + if (this.isUserFd) { |
| 98 | + process.nextTick(function tick() { |
| 99 | + req.oncomplete(null); |
| 100 | + }); |
| 101 | + return; |
| 102 | + } |
| 103 | + |
| 104 | + close(this.fd, req); |
| 105 | + } |
| 106 | +} |
| 107 | + |
| 108 | +module.exports = ReadFileContext; |
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