import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

netwerk/cache/nsCacheMetaData.cpp

@@ -0,0 +1,162 @@
+/* -*- 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;
+        MOZ_ASSERT(value < limit, "Cache Metadata corrupted");
+        if (strcmp(data, key) == 0)
+            return value;
+
+        // Skip value part
+        data = value + strlen(value) + 1;
+    }
+    MOZ_ASSERT(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;
+        MOZ_ASSERT(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;
+    }
+    MOZ_ASSERT(data == limit, "Metadata corrupted");
+    return NS_OK;
+}
+
+nsresult
+nsCacheMetaData::EnsureBuffer(uint32_t bufSize)
+{
+    if (mBufferSize < bufSize) {
+        char * buf = (char *)realloc(mBuffer, bufSize);
+        if (!buf) {
+            return NS_ERROR_OUT_OF_MEMORY;
+        }
+        mBuffer = buf;
+        mBufferSize = bufSize;
+    }
+    return NS_OK;
+}