The Tor Browser / file comparison
comparison: netwerk/cache/nsCacheMetaData.cpp
netwerk/cache/nsCacheMetaData.cpp
- branch
- TOR_BUG_9701
- changeset 9
- a63d609f5ebe
equal
deleted
inserted
replaced
| -1:000000000000 | 0:1ffebcc29f8f |
|---|---|
| 1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- | |
| 2 * | |
| 3 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 #include "nsCacheMetaData.h" | |
| 8 #include "nsICacheEntryDescriptor.h" | |
| 9 | |
| 10 const char * | |
| 11 nsCacheMetaData::GetElement(const char * key) | |
| 12 { | |
| 13 const char * data = mBuffer; | |
| 14 const char * limit = mBuffer + mMetaSize; | |
| 15 | |
| 16 while (data < limit) { | |
| 17 // Point to the value part | |
| 18 const char * value = data + strlen(data) + 1; | |
| 19 NS_ABORT_IF_FALSE(value < limit, "Cache Metadata corrupted"); | |
| 20 if (strcmp(data, key) == 0) | |
| 21 return value; | |
| 22 | |
| 23 // Skip value part | |
| 24 data = value + strlen(value) + 1; | |
| 25 } | |
| 26 NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted"); | |
| 27 return nullptr; | |
| 28 } | |
| 29 | |
| 30 | |
| 31 nsresult | |
| 32 nsCacheMetaData::SetElement(const char * key, | |
| 33 const char * value) | |
| 34 { | |
| 35 const uint32_t keySize = strlen(key) + 1; | |
| 36 char * pos = (char *)GetElement(key); | |
| 37 | |
| 38 if (!value) { | |
| 39 // No value means remove the key/value pair completely, if existing | |
| 40 if (pos) { | |
| 41 uint32_t oldValueSize = strlen(pos) + 1; | |
| 42 uint32_t offset = pos - mBuffer; | |
| 43 uint32_t remainder = mMetaSize - (offset + oldValueSize); | |
| 44 | |
| 45 memmove(pos - keySize, pos + oldValueSize, remainder); | |
| 46 mMetaSize -= keySize + oldValueSize; | |
| 47 } | |
| 48 return NS_OK; | |
| 49 } | |
| 50 | |
| 51 const uint32_t valueSize = strlen(value) + 1; | |
| 52 uint32_t newSize = mMetaSize + valueSize; | |
| 53 if (pos) { | |
| 54 const uint32_t oldValueSize = strlen(pos) + 1; | |
| 55 const uint32_t offset = pos - mBuffer; | |
| 56 const uint32_t remainder = mMetaSize - (offset + oldValueSize); | |
| 57 | |
| 58 // Update the value in place | |
| 59 newSize -= oldValueSize; | |
| 60 nsresult rv = EnsureBuffer(newSize); | |
| 61 NS_ENSURE_SUCCESS(rv, rv); | |
| 62 | |
| 63 // Move the remainder to the right place | |
| 64 pos = mBuffer + offset; | |
| 65 memmove(pos + valueSize, pos + oldValueSize, remainder); | |
| 66 } else { | |
| 67 // allocate new meta data element | |
| 68 newSize += keySize; | |
| 69 nsresult rv = EnsureBuffer(newSize); | |
| 70 NS_ENSURE_SUCCESS(rv, rv); | |
| 71 | |
| 72 // Add after last element | |
| 73 pos = mBuffer + mMetaSize; | |
| 74 memcpy(pos, key, keySize); | |
| 75 pos += keySize; | |
| 76 } | |
| 77 | |
| 78 // Update value | |
| 79 memcpy(pos, value, valueSize); | |
| 80 mMetaSize = newSize; | |
| 81 | |
| 82 return NS_OK; | |
| 83 } | |
| 84 | |
| 85 nsresult | |
| 86 nsCacheMetaData::FlattenMetaData(char * buffer, uint32_t bufSize) | |
| 87 { | |
| 88 if (mMetaSize > bufSize) { | |
| 89 NS_ERROR("buffer size too small for meta data."); | |
| 90 return NS_ERROR_OUT_OF_MEMORY; | |
| 91 } | |
| 92 | |
| 93 memcpy(buffer, mBuffer, mMetaSize); | |
| 94 return NS_OK; | |
| 95 } | |
| 96 | |
| 97 nsresult | |
| 98 nsCacheMetaData::UnflattenMetaData(const char * data, uint32_t size) | |
| 99 { | |
| 100 if (data && size) { | |
| 101 // Check if the metadata ends with a zero byte. | |
| 102 if (data[size-1] != '\0') { | |
| 103 NS_ERROR("Cache MetaData is not null terminated"); | |
| 104 return NS_ERROR_ILLEGAL_VALUE; | |
| 105 } | |
| 106 // Check that there are an even number of zero bytes | |
| 107 // to match the pattern { key \0 value \0 } | |
| 108 bool odd = false; | |
| 109 for (uint32_t i = 0; i < size; i++) { | |
| 110 if (data[i] == '\0') | |
| 111 odd = !odd; | |
| 112 } | |
| 113 if (odd) { | |
| 114 NS_ERROR("Cache MetaData is malformed"); | |
| 115 return NS_ERROR_ILLEGAL_VALUE; | |
| 116 } | |
| 117 | |
| 118 nsresult rv = EnsureBuffer(size); | |
| 119 NS_ENSURE_SUCCESS(rv, rv); | |
| 120 | |
| 121 memcpy(mBuffer, data, size); | |
| 122 mMetaSize = size; | |
| 123 } | |
| 124 return NS_OK; | |
| 125 } | |
| 126 | |
| 127 nsresult | |
| 128 nsCacheMetaData::VisitElements(nsICacheMetaDataVisitor * visitor) | |
| 129 { | |
| 130 const char * data = mBuffer; | |
| 131 const char * limit = mBuffer + mMetaSize; | |
| 132 | |
| 133 while (data < limit) { | |
| 134 const char * key = data; | |
| 135 // Skip key part | |
| 136 data += strlen(data) + 1; | |
| 137 NS_ABORT_IF_FALSE(data < limit, "Metadata corrupted"); | |
| 138 bool keepGoing; | |
| 139 nsresult rv = visitor->VisitMetaDataElement(key, data, &keepGoing); | |
| 140 if (NS_FAILED(rv) || !keepGoing) | |
| 141 return NS_OK; | |
| 142 | |
| 143 // Skip value part | |
| 144 data += strlen(data) + 1; | |
| 145 } | |
| 146 NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted"); | |
| 147 return NS_OK; | |
| 148 } | |
| 149 | |
| 150 nsresult | |
| 151 nsCacheMetaData::EnsureBuffer(uint32_t bufSize) | |
| 152 { | |
| 153 if (mBufferSize < bufSize) { | |
| 154 char * buf = (char *)moz_realloc(mBuffer, bufSize); | |
| 155 if (!buf) { | |
| 156 return NS_ERROR_OUT_OF_MEMORY; | |
| 157 } | |
| 158 mBuffer = buf; | |
| 159 mBufferSize = bufSize; | |
| 160 } | |
| 161 return NS_OK; | |
| 162 } |
