1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/netwerk/cache/nsCacheMetaData.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,162 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + *
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "nsCacheMetaData.h"
1.11 +#include "nsICacheEntryDescriptor.h"
1.12 +
1.13 +const char *
1.14 +nsCacheMetaData::GetElement(const char * key)
1.15 +{
1.16 + const char * data = mBuffer;
1.17 + const char * limit = mBuffer + mMetaSize;
1.18 +
1.19 + while (data < limit) {
1.20 + // Point to the value part
1.21 + const char * value = data + strlen(data) + 1;
1.22 + NS_ABORT_IF_FALSE(value < limit, "Cache Metadata corrupted");
1.23 + if (strcmp(data, key) == 0)
1.24 + return value;
1.25 +
1.26 + // Skip value part
1.27 + data = value + strlen(value) + 1;
1.28 + }
1.29 + NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted");
1.30 + return nullptr;
1.31 +}
1.32 +
1.33 +
1.34 +nsresult
1.35 +nsCacheMetaData::SetElement(const char * key,
1.36 + const char * value)
1.37 +{
1.38 + const uint32_t keySize = strlen(key) + 1;
1.39 + char * pos = (char *)GetElement(key);
1.40 +
1.41 + if (!value) {
1.42 + // No value means remove the key/value pair completely, if existing
1.43 + if (pos) {
1.44 + uint32_t oldValueSize = strlen(pos) + 1;
1.45 + uint32_t offset = pos - mBuffer;
1.46 + uint32_t remainder = mMetaSize - (offset + oldValueSize);
1.47 +
1.48 + memmove(pos - keySize, pos + oldValueSize, remainder);
1.49 + mMetaSize -= keySize + oldValueSize;
1.50 + }
1.51 + return NS_OK;
1.52 + }
1.53 +
1.54 + const uint32_t valueSize = strlen(value) + 1;
1.55 + uint32_t newSize = mMetaSize + valueSize;
1.56 + if (pos) {
1.57 + const uint32_t oldValueSize = strlen(pos) + 1;
1.58 + const uint32_t offset = pos - mBuffer;
1.59 + const uint32_t remainder = mMetaSize - (offset + oldValueSize);
1.60 +
1.61 + // Update the value in place
1.62 + newSize -= oldValueSize;
1.63 + nsresult rv = EnsureBuffer(newSize);
1.64 + NS_ENSURE_SUCCESS(rv, rv);
1.65 +
1.66 + // Move the remainder to the right place
1.67 + pos = mBuffer + offset;
1.68 + memmove(pos + valueSize, pos + oldValueSize, remainder);
1.69 + } else {
1.70 + // allocate new meta data element
1.71 + newSize += keySize;
1.72 + nsresult rv = EnsureBuffer(newSize);
1.73 + NS_ENSURE_SUCCESS(rv, rv);
1.74 +
1.75 + // Add after last element
1.76 + pos = mBuffer + mMetaSize;
1.77 + memcpy(pos, key, keySize);
1.78 + pos += keySize;
1.79 + }
1.80 +
1.81 + // Update value
1.82 + memcpy(pos, value, valueSize);
1.83 + mMetaSize = newSize;
1.84 +
1.85 + return NS_OK;
1.86 +}
1.87 +
1.88 +nsresult
1.89 +nsCacheMetaData::FlattenMetaData(char * buffer, uint32_t bufSize)
1.90 +{
1.91 + if (mMetaSize > bufSize) {
1.92 + NS_ERROR("buffer size too small for meta data.");
1.93 + return NS_ERROR_OUT_OF_MEMORY;
1.94 + }
1.95 +
1.96 + memcpy(buffer, mBuffer, mMetaSize);
1.97 + return NS_OK;
1.98 +}
1.99 +
1.100 +nsresult
1.101 +nsCacheMetaData::UnflattenMetaData(const char * data, uint32_t size)
1.102 +{
1.103 + if (data && size) {
1.104 + // Check if the metadata ends with a zero byte.
1.105 + if (data[size-1] != '\0') {
1.106 + NS_ERROR("Cache MetaData is not null terminated");
1.107 + return NS_ERROR_ILLEGAL_VALUE;
1.108 + }
1.109 + // Check that there are an even number of zero bytes
1.110 + // to match the pattern { key \0 value \0 }
1.111 + bool odd = false;
1.112 + for (uint32_t i = 0; i < size; i++) {
1.113 + if (data[i] == '\0')
1.114 + odd = !odd;
1.115 + }
1.116 + if (odd) {
1.117 + NS_ERROR("Cache MetaData is malformed");
1.118 + return NS_ERROR_ILLEGAL_VALUE;
1.119 + }
1.120 +
1.121 + nsresult rv = EnsureBuffer(size);
1.122 + NS_ENSURE_SUCCESS(rv, rv);
1.123 +
1.124 + memcpy(mBuffer, data, size);
1.125 + mMetaSize = size;
1.126 + }
1.127 + return NS_OK;
1.128 +}
1.129 +
1.130 +nsresult
1.131 +nsCacheMetaData::VisitElements(nsICacheMetaDataVisitor * visitor)
1.132 +{
1.133 + const char * data = mBuffer;
1.134 + const char * limit = mBuffer + mMetaSize;
1.135 +
1.136 + while (data < limit) {
1.137 + const char * key = data;
1.138 + // Skip key part
1.139 + data += strlen(data) + 1;
1.140 + NS_ABORT_IF_FALSE(data < limit, "Metadata corrupted");
1.141 + bool keepGoing;
1.142 + nsresult rv = visitor->VisitMetaDataElement(key, data, &keepGoing);
1.143 + if (NS_FAILED(rv) || !keepGoing)
1.144 + return NS_OK;
1.145 +
1.146 + // Skip value part
1.147 + data += strlen(data) + 1;
1.148 + }
1.149 + NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted");
1.150 + return NS_OK;
1.151 +}
1.152 +
1.153 +nsresult
1.154 +nsCacheMetaData::EnsureBuffer(uint32_t bufSize)
1.155 +{
1.156 + if (mBufferSize < bufSize) {
1.157 + char * buf = (char *)moz_realloc(mBuffer, bufSize);
1.158 + if (!buf) {
1.159 + return NS_ERROR_OUT_OF_MEMORY;
1.160 + }
1.161 + mBuffer = buf;
1.162 + mBufferSize = bufSize;
1.163 + }
1.164 + return NS_OK;
1.165 +}
