hphp/util/brotli.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #include "hphp/util/brotli.h"
  18
  19 #include "hphp/util/alloc.h"
  20 #include "hphp/util/exception.h"
  21 #include "hphp/util/logger.h"
  22
  23 #include <brotli/encode.h>
  24
  25 namespace HPHP {
  26 ///////////////////////////////////////////////////////////////////////////////
  27
  28 bool g_brotliUseLocalArena = false;
  29
  30 namespace {
  31 void *brotlialloc(void * /*opaque*/, size_t size) {
  32   if (g_brotliUseLocalArena) {
  33     return local_malloc(size);
  34   } else {
  35     return malloc(size);
  36   }
  37 }
  38
  39 void brotlifree(void * /*opaque*/, void *address) {
  40   if (g_brotliUseLocalArena) {
  41     local_free(address);
  42   } else {
  43     free(address);
  44   }
  45 }
  46 } // namespace
  47
  48 BrotliCompressor::BrotliCompressor(BrotliEncoderMode mode, uint32_t quality, uint32_t lgWin) {
  49   if (quality < BROTLI_MIN_QUALITY || quality > BROTLI_MAX_QUALITY) {
  50     Logger::Info("brotli compression quality (%d) must be within %d..%d, clamping...", quality, BROTLI_MIN_QUALITY, BROTLI_MAX_QUALITY);
  51     if (quality < BROTLI_MIN_QUALITY) {
  52       quality = BROTLI_MIN_QUALITY;
  53     } else {
  54       quality = BROTLI_MAX_QUALITY;
  55     }
  56   }
  57
  58   if (lgWin < BROTLI_MIN_WINDOW_BITS || lgWin > BROTLI_MAX_WINDOW_BITS) {
  59     Logger::Info("brotli window size (%d) must be within %d..%d, clamping...", lgWin, BROTLI_MIN_WINDOW_BITS, BROTLI_MAX_WINDOW_BITS);
  60     if (lgWin < BROTLI_MIN_WINDOW_BITS) {
  61       lgWin = BROTLI_MIN_WINDOW_BITS;
  62     } else {
  63       lgWin = BROTLI_MAX_WINDOW_BITS;
  64     }
  65   }
  66
  67   m_encState.reset(BrotliEncoderCreateInstance(brotlialloc, brotlifree, nullptr));
  68   if (!m_encState) {
  69     throw Exception("Failed to create brotli encoder instance");
  70   }
  71
  72   if (BrotliEncoderSetParameter(m_encState.get(), BROTLI_PARAM_MODE, mode) != BROTLI_TRUE) {
  73     throw Exception("Failed to set brotli mode(%d)", static_cast<uint32_t>(mode));
  74   }
  75
  76   if (BrotliEncoderSetParameter(m_encState.get(), BROTLI_PARAM_QUALITY, quality) != BROTLI_TRUE) {
  77     throw Exception("Failed to set quality(%d)", quality);
  78   }
  79
  80   if (BrotliEncoderSetParameter(m_encState.get(), BROTLI_PARAM_LGWIN, lgWin) != BROTLI_TRUE) {
  81     throw Exception("Failed to set lgWin(%d)", lgWin);
  82   }
  83 }
  84
  85 StringHolder BrotliCompressor::compress(const void* data,
  86                                         size_t& len,
  87                                         bool last) {
  88   // Brotli does not have a utility to compute max size of the buffer
  89   // for the stream-based API. Below link discusses some numbers
  90   // and formula where 16MB block would use only 6 extra bytes.
  91   // For all practical usage we should be fine with 20 bytes.
  92   // https://github.com/google/brotli/issues/274
  93   // We should also allow 6 extra bytes for an empty meta-block at
  94   // the end of each chunk to force "flush".
  95   size_t availableBytes = len + 30;
  96
  97   StringHolder available;
  98   void* availablePtr;
  99   if (g_brotliUseLocalArena) {
 100     availablePtr = local_malloc(availableBytes);
 101     available = StringHolder(static_cast<char*>(availablePtr),
 102                              availableBytes,
 103                              FreeType::LocalFree);
 104   } else {
 105     availablePtr = malloc(availableBytes);
 106     available = StringHolder(static_cast<char*>(availablePtr),
 107                              availableBytes,
 108                              FreeType::Free);
 109   }
 110
 111   auto buf = static_cast<uint8_t*>(availablePtr);
 112   size_t inLength = len;
 113   auto inBuf = static_cast<const uint8_t *>(data);
 114   size_t remainingOut = availableBytes;
 115
 116   // This ought to complete in one call
 117   if (BrotliEncoderCompressStream(
 118         m_encState.get(),
 119         last ? BROTLI_OPERATION_FINISH : BROTLI_OPERATION_FLUSH,
 120         &inLength,
 121         &inBuf,
 122         &remainingOut,
 123         &buf,
 124         nullptr) != BROTLI_TRUE) {
 125     Logger::Error("Compression encountered an error");
 126     return nullptr;
 127   }
 128
 129   // This means the encoder didn't successfully encode + flush all data.
 130   if (inLength != 0 ||
 131       BrotliEncoderHasMoreOutput(m_encState.get())) {
 132     Logger::Error("Compression didn't flush all data");
 133     return nullptr;
 134   }
 135
 136   len = availableBytes - remainingOut;
 137   available.shrinkTo(len);
 138
 139   return available;
 140 }
 141
 142 ///////////////////////////////////////////////////////////////////////////////
 143 }