|
| 1 | +package gws |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "encoding/binary" |
| 6 | + "errors" |
| 7 | + "io" |
| 8 | + "math" |
| 9 | + |
| 10 | + "github.com/klauspost/compress/flate" |
| 11 | + "github.com/lxzan/gws/internal" |
| 12 | +) |
| 13 | + |
| 14 | +const segmentSize = 128 * 1024 |
| 15 | + |
| 16 | +// 获取大文件压缩器 |
| 17 | +// Get bigDeflater |
| 18 | +func (c *Conn) getBigDeflater() *bigDeflater { |
| 19 | + if c.isServer { |
| 20 | + return c.config.bdPool.Get() |
| 21 | + } |
| 22 | + return (*bigDeflater)(c.deflater.cpsWriter) |
| 23 | +} |
| 24 | + |
| 25 | +// 回收大文件压缩器 |
| 26 | +// Recycle bigDeflater |
| 27 | +func (c *Conn) putBigDeflater(d *bigDeflater) { |
| 28 | + if c.isServer { |
| 29 | + c.config.bdPool.Put(d) |
| 30 | + } |
| 31 | +} |
| 32 | + |
| 33 | +// 拆分io.Reader为小切片 |
| 34 | +// Split io.Reader into small slices |
| 35 | +func (c *Conn) splitReader(r io.Reader, f func(index int, eof bool, p []byte) error) error { |
| 36 | + var buf = binaryPool.Get(segmentSize) |
| 37 | + defer binaryPool.Put(buf) |
| 38 | + |
| 39 | + var p = buf.Bytes()[:segmentSize] |
| 40 | + var n, index = 0, 0 |
| 41 | + var err error |
| 42 | + for n, err = r.Read(p); err == nil || errors.Is(err, io.EOF); n, err = r.Read(p) { |
| 43 | + eof := errors.Is(err, io.EOF) |
| 44 | + if err = f(index, eof, p[:n]); err != nil { |
| 45 | + return err |
| 46 | + } |
| 47 | + index++ |
| 48 | + if eof { |
| 49 | + break |
| 50 | + } |
| 51 | + } |
| 52 | + return err |
| 53 | +} |
| 54 | + |
| 55 | +// WriteFile 大文件写入 |
| 56 | +// 采用分段写入技术, 减少写入过程中的内存占用 |
| 57 | +// Segmented write technology to reduce memory usage during write process |
| 58 | +func (c *Conn) WriteFile(opcode Opcode, payload io.Reader) error { |
| 59 | + err := c.doWriteFile(opcode, payload) |
| 60 | + c.emitError(err) |
| 61 | + return err |
| 62 | +} |
| 63 | + |
| 64 | +func (c *Conn) doWriteFile(opcode Opcode, payload io.Reader) error { |
| 65 | + c.mu.Lock() |
| 66 | + defer c.mu.Unlock() |
| 67 | + |
| 68 | + var cb = func(index int, eof bool, p []byte) error { |
| 69 | + if index > 0 { |
| 70 | + opcode = OpcodeContinuation |
| 71 | + } |
| 72 | + frame, err := c.genFrame(opcode, internal.Bytes(p), frameConfig{ |
| 73 | + fin: eof, |
| 74 | + compress: false, |
| 75 | + broadcast: false, |
| 76 | + checkEncoding: false, |
| 77 | + }) |
| 78 | + if err != nil { |
| 79 | + return err |
| 80 | + } |
| 81 | + if c.pd.Enabled && index == 0 { |
| 82 | + frame.Bytes()[0] |= uint8(64) |
| 83 | + } |
| 84 | + if c.isClosed() { |
| 85 | + return ErrConnClosed |
| 86 | + } |
| 87 | + err = internal.WriteN(c.conn, frame.Bytes()) |
| 88 | + binaryPool.Put(frame) |
| 89 | + return err |
| 90 | + } |
| 91 | + |
| 92 | + if c.pd.Enabled { |
| 93 | + var deflater = c.getBigDeflater() |
| 94 | + var fw = &flateWriter{cb: cb} |
| 95 | + err := deflater.Compress(payload, fw, c.getCpsDict(false), &c.cpsWindow) |
| 96 | + c.putBigDeflater(deflater) |
| 97 | + return err |
| 98 | + } else { |
| 99 | + return c.splitReader(payload, cb) |
| 100 | + } |
| 101 | +} |
| 102 | + |
| 103 | +// 大文件压缩器 |
| 104 | +type bigDeflater flate.Writer |
| 105 | + |
| 106 | +// 创建大文件压缩器 |
| 107 | +// Create a bigDeflater |
| 108 | +func newBigDeflater(isServer bool, options PermessageDeflate) *bigDeflater { |
| 109 | + windowBits := internal.SelectValue(isServer, options.ServerMaxWindowBits, options.ClientMaxWindowBits) |
| 110 | + if windowBits == 15 { |
| 111 | + cpsWriter, _ := flate.NewWriter(nil, options.Level) |
| 112 | + return (*bigDeflater)(cpsWriter) |
| 113 | + } else { |
| 114 | + cpsWriter, _ := flate.NewWriterWindow(nil, internal.BinaryPow(windowBits)) |
| 115 | + return (*bigDeflater)(cpsWriter) |
| 116 | + } |
| 117 | +} |
| 118 | + |
| 119 | +func (c *bigDeflater) FlateWriter() *flate.Writer { return (*flate.Writer)(c) } |
| 120 | + |
| 121 | +// Compress 压缩 |
| 122 | +func (c *bigDeflater) Compress(src io.Reader, dst *flateWriter, dict []byte, sw *slideWindow) error { |
| 123 | + if err := compressTo(c.FlateWriter(), &readerWrapper{r: src, sw: sw}, dst, dict); err != nil { |
| 124 | + return err |
| 125 | + } |
| 126 | + return dst.Flush() |
| 127 | +} |
| 128 | + |
| 129 | +// 写入代理 |
| 130 | +// 将切片透传给回调函数, 以实现分段写入功能 |
| 131 | +// Write proxy |
| 132 | +// Passthrough slices to the callback function for segmented writes. |
| 133 | +type flateWriter struct { |
| 134 | + index int |
| 135 | + buffers []*bytes.Buffer |
| 136 | + cb func(index int, eof bool, p []byte) error |
| 137 | +} |
| 138 | + |
| 139 | +// 是否可以执行回调函数 |
| 140 | +// Whether the callback function can be executed |
| 141 | +func (c *flateWriter) shouldCall() bool { |
| 142 | + var n = len(c.buffers) |
| 143 | + if n < 2 { |
| 144 | + return false |
| 145 | + } |
| 146 | + var sum = 0 |
| 147 | + for i := 1; i < n; i++ { |
| 148 | + sum += c.buffers[i].Len() |
| 149 | + } |
| 150 | + return sum >= 4 |
| 151 | +} |
| 152 | + |
| 153 | +// 聚合写入, 减少syscall.write调用次数 |
| 154 | +// Aggregate writes, reducing the number of syscall.write calls |
| 155 | +func (c *flateWriter) write(p []byte) { |
| 156 | + if len(c.buffers) == 0 { |
| 157 | + c.buffers = append(c.buffers, binaryPool.Get(segmentSize)) |
| 158 | + } |
| 159 | + var n = len(c.buffers) |
| 160 | + var tail = c.buffers[n-1] |
| 161 | + if tail.Len()+len(p)+frameHeaderSize > tail.Cap() { |
| 162 | + tail = binaryPool.Get(segmentSize) |
| 163 | + c.buffers = append(c.buffers, tail) |
| 164 | + } |
| 165 | + tail.Write(p) |
| 166 | +} |
| 167 | + |
| 168 | +func (c *flateWriter) Write(p []byte) (n int, err error) { |
| 169 | + c.write(p) |
| 170 | + if c.shouldCall() { |
| 171 | + err = c.cb(c.index, false, c.buffers[0].Bytes()) |
| 172 | + binaryPool.Put(c.buffers[0]) |
| 173 | + c.buffers = c.buffers[1:] |
| 174 | + c.index++ |
| 175 | + } |
| 176 | + return n, err |
| 177 | +} |
| 178 | + |
| 179 | +func (c *flateWriter) Flush() error { |
| 180 | + var buf = c.buffers[0] |
| 181 | + for i := 1; i < len(c.buffers); i++ { |
| 182 | + buf.Write(c.buffers[i].Bytes()) |
| 183 | + binaryPool.Put(c.buffers[i]) |
| 184 | + } |
| 185 | + if n := buf.Len(); n >= 4 { |
| 186 | + if tail := buf.Bytes()[n-4:]; binary.BigEndian.Uint32(tail) == math.MaxUint16 { |
| 187 | + buf.Truncate(n - 4) |
| 188 | + } |
| 189 | + } |
| 190 | + var err = c.cb(c.index, true, buf.Bytes()) |
| 191 | + c.index++ |
| 192 | + binaryPool.Put(buf) |
| 193 | + return err |
| 194 | +} |
| 195 | + |
| 196 | +// 将io.Reader包装为io.WriterTo |
| 197 | +// Wrapping io.Reader as io.WriterTo |
| 198 | +type readerWrapper struct { |
| 199 | + r io.Reader |
| 200 | + sw *slideWindow |
| 201 | +} |
| 202 | + |
| 203 | +// WriteTo 写入内容, 并更新字典 |
| 204 | +// Write the contents, and update the dictionary |
| 205 | +func (c *readerWrapper) WriteTo(w io.Writer) (int64, error) { |
| 206 | + var buf = binaryPool.Get(segmentSize) |
| 207 | + defer binaryPool.Put(buf) |
| 208 | + |
| 209 | + var p = buf.Bytes()[:segmentSize] |
| 210 | + var sum, n = 0, 0 |
| 211 | + var err error |
| 212 | + for n, err = c.r.Read(p); err == nil || errors.Is(err, io.EOF); n, err = c.r.Read(p) { |
| 213 | + eof := errors.Is(err, io.EOF) |
| 214 | + if _, err = w.Write(p[:n]); err != nil { |
| 215 | + return int64(sum), err |
| 216 | + } |
| 217 | + sum += n |
| 218 | + _, _ = c.sw.Write(p[:n]) |
| 219 | + if eof { |
| 220 | + break |
| 221 | + } |
| 222 | + } |
| 223 | + return int64(sum), err |
| 224 | +} |
| 225 | + |
| 226 | +func compressTo(cpsWriter *flate.Writer, r io.WriterTo, w io.Writer, dict []byte) error { |
| 227 | + cpsWriter.ResetDict(w, dict) |
| 228 | + if _, err := r.WriteTo(cpsWriter); err != nil { |
| 229 | + return err |
| 230 | + } |
| 231 | + return cpsWriter.Flush() |
| 232 | +} |
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