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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "net/disk_cache/simple/simple_util.h"
      6 
      7 #include <limits>
      8 
      9 #include "base/files/file_util.h"
     10 #include "base/format_macros.h"
     11 #include "base/logging.h"
     12 #include "base/sha1.h"
     13 #include "base/strings/string_number_conversions.h"
     14 #include "base/strings/stringprintf.h"
     15 #include "base/threading/thread_restrictions.h"
     16 #include "base/time/time.h"
     17 #include "net/disk_cache/simple/simple_entry_format.h"
     18 
     19 namespace {
     20 
     21 // Size of the uint64 hash_key number in Hex format in a string.
     22 const size_t kEntryHashKeyAsHexStringSize = 2 * sizeof(uint64);
     23 
     24 // TODO(clamy, gavinp): this should go in base
     25 bool GetNanoSecsFromStat(const struct stat& st,
     26                          time_t* out_sec,
     27                          long* out_nsec) {
     28 #if defined(OS_ANDROID)
     29   *out_sec = st.st_mtime;
     30   *out_nsec = st.st_mtime_nsec;
     31   return true;
     32 #elif defined(OS_LINUX)
     33   *out_sec = st.st_mtim.tv_sec;
     34   *out_nsec = st.st_mtim.tv_nsec;
     35   return true;
     36 #elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
     37   *out_sec = st.st_mtimespec.tv_sec;
     38   *out_nsec = st.st_mtimespec.tv_nsec;
     39   return true;
     40 #else
     41   return false;
     42 #endif
     43 }
     44 
     45 }  // namespace
     46 
     47 namespace disk_cache {
     48 
     49 namespace simple_util {
     50 
     51 std::string ConvertEntryHashKeyToHexString(uint64 hash_key) {
     52   const std::string hash_key_str = base::StringPrintf("%016" PRIx64, hash_key);
     53   DCHECK_EQ(kEntryHashKeyAsHexStringSize, hash_key_str.size());
     54   return hash_key_str;
     55 }
     56 
     57 std::string GetEntryHashKeyAsHexString(const std::string& key) {
     58   std::string hash_key_str =
     59       ConvertEntryHashKeyToHexString(GetEntryHashKey(key));
     60   DCHECK_EQ(kEntryHashKeyAsHexStringSize, hash_key_str.size());
     61   return hash_key_str;
     62 }
     63 
     64 bool GetEntryHashKeyFromHexString(const base::StringPiece& hash_key,
     65                                   uint64* hash_key_out) {
     66   if (hash_key.size() != kEntryHashKeyAsHexStringSize) {
     67     return false;
     68   }
     69   return base::HexStringToUInt64(hash_key, hash_key_out);
     70 }
     71 
     72 uint64 GetEntryHashKey(const std::string& key) {
     73   union {
     74     unsigned char sha_hash[base::kSHA1Length];
     75     uint64 key_hash;
     76   } u;
     77   base::SHA1HashBytes(reinterpret_cast<const unsigned char*>(key.data()),
     78                       key.size(), u.sha_hash);
     79   return u.key_hash;
     80 }
     81 
     82 std::string GetFilenameFromEntryHashAndFileIndex(uint64 entry_hash,
     83                                                  int file_index) {
     84   return base::StringPrintf("%016" PRIx64 "_%1d", entry_hash, file_index);
     85 }
     86 
     87 std::string GetSparseFilenameFromEntryHash(uint64 entry_hash) {
     88   return base::StringPrintf("%016" PRIx64 "_s", entry_hash);
     89 }
     90 
     91 std::string GetFilenameFromKeyAndFileIndex(const std::string& key,
     92                                            int file_index) {
     93   return GetEntryHashKeyAsHexString(key) +
     94          base::StringPrintf("_%1d", file_index);
     95 }
     96 
     97 int32 GetDataSizeFromKeyAndFileSize(const std::string& key, int64 file_size) {
     98   int64 data_size = file_size - key.size() - sizeof(SimpleFileHeader) -
     99                     sizeof(SimpleFileEOF);
    100   DCHECK_GE(implicit_cast<int64>(std::numeric_limits<int32>::max()), data_size);
    101   return data_size;
    102 }
    103 
    104 int64 GetFileSizeFromKeyAndDataSize(const std::string& key, int32 data_size) {
    105   return data_size + key.size() + sizeof(SimpleFileHeader) +
    106       sizeof(SimpleFileEOF);
    107 }
    108 
    109 int GetFileIndexFromStreamIndex(int stream_index) {
    110   return (stream_index == 2) ? 1 : 0;
    111 }
    112 
    113 // TODO(clamy, gavinp): this should go in base
    114 bool GetMTime(const base::FilePath& path, base::Time* out_mtime) {
    115   DCHECK(out_mtime);
    116 #if defined(OS_POSIX)
    117   base::ThreadRestrictions::AssertIOAllowed();
    118   struct stat file_stat;
    119   if (stat(path.value().c_str(), &file_stat) != 0)
    120     return false;
    121   time_t sec;
    122   long nsec;
    123   if (GetNanoSecsFromStat(file_stat, &sec, &nsec)) {
    124     int64 usec = (nsec / base::Time::kNanosecondsPerMicrosecond);
    125     *out_mtime = base::Time::FromTimeT(sec)
    126         + base::TimeDelta::FromMicroseconds(usec);
    127     return true;
    128   }
    129 #endif
    130   base::File::Info file_info;
    131   if (!base::GetFileInfo(path, &file_info))
    132     return false;
    133   *out_mtime = file_info.last_modified;
    134   return true;
    135 }
    136 
    137 }  // namespace simple_backend
    138 
    139 }  // namespace disk_cache
    140