The Tor Browser: netwerk/cache/nsCacheMetaData.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsCacheMetaData.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsCacheMetaData.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsCacheMetaData.h"
 #include "nsICacheEntryDescriptor.h"
 const char *
 nsCacheMetaData::GetElement(const char * key)
 {
     const char * data = mBuffer;
     const char * limit = mBuffer + mMetaSize;
     while (data < limit) {
         // Point to the value part
         const char * value = data + strlen(data) + 1;
         NS_ABORT_IF_FALSE(value < limit, "Cache Metadata corrupted");
         if (strcmp(data, key) == 0)
             return value;
         // Skip value part
         data = value + strlen(value) + 1;
     }
     NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted");
     return nullptr;
 }
 nsresult
 nsCacheMetaData::SetElement(const char * key,
                             const char * value)
 {
     const uint32_t keySize = strlen(key) + 1;
     char * pos = (char *)GetElement(key);
     if (!value) {
         // No value means remove the key/value pair completely, if existing
         if (pos) {
             uint32_t oldValueSize = strlen(pos) + 1;
             uint32_t offset = pos - mBuffer;
             uint32_t remainder = mMetaSize - (offset + oldValueSize);
             memmove(pos - keySize, pos + oldValueSize, remainder);
             mMetaSize -= keySize + oldValueSize;
         }
         return NS_OK;
     }
     const uint32_t valueSize = strlen(value) + 1;
     uint32_t newSize = mMetaSize + valueSize;
     if (pos) {
         const uint32_t oldValueSize = strlen(pos) + 1;
         const uint32_t offset = pos - mBuffer;
         const uint32_t remainder = mMetaSize - (offset + oldValueSize);
         // Update the value in place
         newSize -= oldValueSize;
         nsresult rv = EnsureBuffer(newSize);
         NS_ENSURE_SUCCESS(rv, rv);
         // Move the remainder to the right place
         pos = mBuffer + offset;
         memmove(pos + valueSize, pos + oldValueSize, remainder);
     } else {
         // allocate new meta data element
         newSize += keySize;
         nsresult rv = EnsureBuffer(newSize);
         NS_ENSURE_SUCCESS(rv, rv);
         // Add after last element
         pos = mBuffer + mMetaSize;
         memcpy(pos, key, keySize);
         pos += keySize;
     }
     // Update value
     memcpy(pos, value, valueSize);
     mMetaSize = newSize;
     return NS_OK;
 }
 nsresult
 nsCacheMetaData::FlattenMetaData(char * buffer, uint32_t bufSize)
 {
     if (mMetaSize > bufSize) {
         NS_ERROR("buffer size too small for meta data.");
         return NS_ERROR_OUT_OF_MEMORY;
     }
     memcpy(buffer, mBuffer, mMetaSize);
     return NS_OK;
 }
 nsresult
 nsCacheMetaData::UnflattenMetaData(const char * data, uint32_t size)
 {
     if (data && size) {
         // Check if the metadata ends with a zero byte.
         if (data[size-1] != '\0') {
             NS_ERROR("Cache MetaData is not null terminated");
             return NS_ERROR_ILLEGAL_VALUE;
         }
         // Check that there are an even number of zero bytes
         // to match the pattern { key \0 value \0 }
         bool odd = false;
         for (uint32_t i = 0; i < size; i++) {
             if (data[i] == '\0')
                 odd = !odd;
         }
         if (odd) {
             NS_ERROR("Cache MetaData is malformed");
             return NS_ERROR_ILLEGAL_VALUE;
         }
         nsresult rv = EnsureBuffer(size);
         NS_ENSURE_SUCCESS(rv, rv);
         memcpy(mBuffer, data, size);
         mMetaSize = size;
     }
     return NS_OK;
 }
 nsresult
 nsCacheMetaData::VisitElements(nsICacheMetaDataVisitor * visitor)
 {
     const char * data = mBuffer;
     const char * limit = mBuffer + mMetaSize;
     while (data < limit) {
         const char * key = data;
         // Skip key part
         data += strlen(data) + 1;
         NS_ABORT_IF_FALSE(data < limit, "Metadata corrupted");
         bool keepGoing;
         nsresult rv = visitor->VisitMetaDataElement(key, data, &keepGoing);
         if (NS_FAILED(rv) || !keepGoing)
             return NS_OK;
         // Skip value part
         data += strlen(data) + 1;
     }
     NS_ABORT_IF_FALSE(data == limit, "Metadata corrupted");
     return NS_OK;
 }
 nsresult
 nsCacheMetaData::EnsureBuffer(uint32_t bufSize)
 {
     if (mBufferSize < bufSize) {
         char * buf = (char *)moz_realloc(mBuffer, bufSize);
         if (!buf) {
             return NS_ERROR_OUT_OF_MEMORY;
         }
         mBuffer = buf;
         mBufferSize = bufSize;
     }
     return NS_OK;
 }

The Tor Browser / annotate

netwerk/cache/nsCacheMetaData.cpp@b8a032363ba2 (annotated)

netwerk/cache/nsCacheMetaData.cpp