/*
 * Copyright (C) 2014 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "config.h"
#import "DiskCacheMonitorCocoa.h"

#import "CachedResource.h"
#import "MemoryCache.h"
#import "SharedBuffer.h"
#import <pal/spi/cf/CFNetworkSPI.h>
#import <wtf/MainThread.h>
#import <wtf/RefPtr.h>

#if USE(WEB_THREAD)
#import "WebCoreThreadRun.h"
#endif

namespace WebCore {

// The maximum number of seconds we'll try to wait for a resource to be disk cached before we forget the request.
static const double diskCacheMonitorTimeout = 20;

RefPtr<SharedBuffer> DiskCacheMonitor::tryGetFileBackedSharedBufferFromCFURLCachedResponse(CFCachedURLResponseRef cachedResponse)
{
    auto data = _CFCachedURLResponseGetMemMappedData(cachedResponse);
    if (!data)
        return nullptr;

    return SharedBuffer::create(data);
}

void DiskCacheMonitor::monitorFileBackingStoreCreation(const ResourceRequest& request, PAL::SessionID sessionID, CFCachedURLResponseRef cachedResponse)
{
    if (!cachedResponse)
        return;

    // FIXME: It's not good to have the new here, but the delete inside the constructor. Reconsider this design.
    new DiskCacheMonitor(request, sessionID, cachedResponse); // Balanced by delete and unique_ptr in the blocks set up in the constructor, one of which is guaranteed to run.
}

DiskCacheMonitor::DiskCacheMonitor(const ResourceRequest& request, PAL::SessionID sessionID, CFCachedURLResponseRef cachedResponse)
    : m_resourceRequest(request)
    , m_sessionID(sessionID)
{
    ASSERT(isMainThread());

    // Set up a delayed callback to cancel this monitor if the resource hasn't been cached yet.
    __block DiskCacheMonitor* rawMonitor = this;
    auto cancelMonitorBlock = ^{
        delete rawMonitor; // Balanced by "new DiskCacheMonitor" in monitorFileBackingStoreCreation.
        rawMonitor = nullptr;
    };

#if USE(WEB_THREAD)
    auto cancelMonitorBlockToRun = ^{
        WebThreadRun(cancelMonitorBlock);
    };
#else
    auto cancelMonitorBlockToRun = cancelMonitorBlock;
#endif

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC * diskCacheMonitorTimeout), dispatch_get_main_queue(), cancelMonitorBlockToRun);

    // Set up the disk caching callback to create the ShareableResource and send it to the WebProcess.
    auto block = ^(CFCachedURLResponseRef cachedResponse) {
        ASSERT(isMainThread());
        // If the monitor isn't there then it timed out before this resource was cached to disk.
        if (!rawMonitor)
            return;

        auto monitor = std::unique_ptr<DiskCacheMonitor>(rawMonitor); // Balanced by "new DiskCacheMonitor" in monitorFileBackingStoreCreation.
        rawMonitor = nullptr;

        auto fileBackedBuffer = DiskCacheMonitor::tryGetFileBackedSharedBufferFromCFURLCachedResponse(cachedResponse);
        if (!fileBackedBuffer)
            return;

        monitor->resourceBecameFileBacked(*fileBackedBuffer);
    };

#if USE(WEB_THREAD)
    auto blockToRun = ^(CFCachedURLResponseRef response) {
        auto strongResponse = retainPtr(response);
        WebThreadRun(^{
            block(strongResponse.get());
        });
    };
#else
    auto blockToRun = block;
#endif
    _CFCachedURLResponseSetBecameFileBackedCallBackBlock(cachedResponse, blockToRun, dispatch_get_main_queue());
}

void DiskCacheMonitor::resourceBecameFileBacked(SharedBuffer& fileBackedBuffer)
{
    auto* resource = MemoryCache::singleton().resourceForRequest(m_resourceRequest, m_sessionID);
    if (!resource)
        return;

    resource->tryReplaceEncodedData(fileBackedBuffer);
}


} // namespace WebCore