/*

 * Copyright (C) 2007 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 COMPUTER, INC. ``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 COMPUTER, INC. OR

 * 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. 

 */

#include "config.h"

#include "WebKitDLL.h"

#include "WebDownload.h"

#include "DefaultDownloadDelegate.h"

#include "MarshallingHelpers.h"

#include "WebError.h"

#include "WebKit.h"

#include "WebKitLogging.h"

#include "WebMutableURLRequest.h"

#include "WebURLAuthenticationChallenge.h"

#include "WebURLCredential.h"

#include "WebURLResponse.h"

#include <wtf/text/CString.h>

#include <io.h>

#include <sys/stat.h>

#include <sys/types.h>

#pragma warning(push, 0)

#include <WebCore/BString.h>

#include <WebCore/NotImplemented.h>

#include <WebCore/ResourceError.h>

#include <WebCore/ResourceHandle.h>

#include <WebCore/ResourceRequest.h>

#include <WebCore/ResourceResponse.h>

#include <wtf/CurrentTime.h>

#include <wtf/StdLibExtras.h>

#pragma warning(pop)

using namespace WebCore;

// Download Bundle file utilities ----------------------------------------------------------------

const String& WebDownload::bundleExtension()

{

   DEFINE_STATIC_LOCAL(const String, bundleExtension, (".download"));

   return bundleExtension;

}

UInt32 WebDownload::bundleMagicNumber()

{

   return 0xDECAF4EA;

}

// WebDownload ----------------------------------------------------------------

WebDownload::WebDownload()

    : m_refCount(0)

{

    gClassCount++;

    gClassNameCount.add("WebDownload");

}

WebDownload::~WebDownload()

{

    LOG(Download, "WebDownload - Destroying download (%p)", this);

    cancel();

    gClassCount--;

    gClassNameCount.remove("WebDownload");

}

WebDownload* WebDownload::createInstance()

{

    WebDownload* instance = new WebDownload();

    instance->AddRef();

    return instance;

}

WebDownload* WebDownload::createInstance(ResourceHandle* handle, const ResourceRequest& request, const ResourceResponse& response, IWebDownloadDelegate* delegate)

{

    WebDownload* instance = new WebDownload();

    instance->AddRef();

    instance->init(handle, request, response, delegate);

    return instance;

}

WebDownload* WebDownload::createInstance(const KURL& url, IWebDownloadDelegate* delegate)

{

    WebDownload* instance = new WebDownload();

    instance->AddRef();

    instance->init(url, delegate);

    return instance;

}

// IUnknown -------------------------------------------------------------------

HRESULT STDMETHODCALLTYPE WebDownload::QueryInterface(REFIID riid, void** ppvObject)

{

    *ppvObject = 0;

    if (IsEqualGUID(riid, IID_IUnknown))

        *ppvObject = static_cast<IWebDownload*>(this);

    else if (IsEqualGUID(riid, IID_IWebDownload))

        *ppvObject = static_cast<IWebDownload*>(this);

    else if (IsEqualGUID(riid, IID_IWebURLAuthenticationChallengeSender))

        *ppvObject = static_cast<IWebURLAuthenticationChallengeSender*>(this);

    else if (IsEqualGUID(riid, CLSID_WebDownload))

        *ppvObject = static_cast<WebDownload*>(this);

    else

        return E_NOINTERFACE;

    AddRef();

    return S_OK;

}

ULONG STDMETHODCALLTYPE WebDownload::AddRef(void)

{

    return ++m_refCount;

}

ULONG STDMETHODCALLTYPE WebDownload::Release(void)

{

    ULONG newRef = --m_refCount;

    if (!newRef)

        delete(this);

    return newRef;

}

// IWebDownload -------------------------------------------------------------------

HRESULT STDMETHODCALLTYPE WebDownload::canResumeDownloadDecodedWithEncodingMIMEType(

        /* [in] */ BSTR, 

        /* [out, retval] */ BOOL*)

{

    notImplemented();

    return E_FAIL;

}

HRESULT STDMETHODCALLTYPE WebDownload::bundlePathForTargetPath(

        /* [in] */ BSTR targetPath, 

        /* [out, retval] */ BSTR* bundlePath)

{

    if (!targetPath)

        return E_INVALIDARG;

    String bundle(targetPath, SysStringLen(targetPath));

    if (bundle.isEmpty())

        return E_INVALIDARG;

    if (bundle[bundle.length()-1] == '/')

        bundle.truncate(1);

    bundle += bundleExtension();

    *bundlePath = SysAllocStringLen(bundle.characters(), bundle.length());

    if (!*bundlePath)

       return E_FAIL;

    return S_OK;

}

HRESULT STDMETHODCALLTYPE WebDownload::request(

        /* [out, retval] */ IWebURLRequest** request)

{

    if (request) {

        *request = m_request.get();

        if (*request)

            (*request)->AddRef();

    }

    return S_OK;

}

// Download Bundle file utilities ----------------------------------------------------------------

CFDataRef WebDownload::extractResumeDataFromBundle(const String& bundlePath)

{

    if (bundlePath.isEmpty()) {

        LOG_ERROR("Cannot create resume data from empty download bundle path");

        return 0;

    }

    // Open a handle to the bundle file

    String nullifiedPath = bundlePath;

    FILE* bundle = 0;

    if (_wfopen_s(&bundle, nullifiedPath.charactersWithNullTermination(), TEXT("r+b")) || !bundle) {

        LOG_ERROR("Failed to open file %s to get resume data", bundlePath.ascii().data());

        return 0;

    }

    CFDataRef result = 0;

    Vector<UInt8> footerBuffer;

    // Stat the file to get its size

    struct _stat64 fileStat;

    if (_fstat64(_fileno(bundle), &fileStat))

        goto exit;

    // Check for the bundle magic number at the end of the file

    fpos_t footerMagicNumberPosition = fileStat.st_size - 4;

    ASSERT(footerMagicNumberPosition >= 0);

    if (footerMagicNumberPosition < 0)

        goto exit;

    if (fsetpos(bundle, &footerMagicNumberPosition))

        goto exit;

    UInt32 footerMagicNumber = 0;

    if (fread(&footerMagicNumber, 4, 1, bundle) != 1) {

        LOG_ERROR("Failed to read footer magic number from the bundle - errno(%i)", errno);  

        goto exit;

    }

    if (footerMagicNumber != bundleMagicNumber()) {

        LOG_ERROR("Footer's magic number does not match 0x%X - errno(%i)", bundleMagicNumber(), errno);  

        goto exit;

    }

    // Now we're *reasonably* sure this is a .download bundle we actually wrote. 

    // Get the length of the resume data

    fpos_t footerLengthPosition = fileStat.st_size - 8;

    ASSERT(footerLengthPosition >= 0);

    if (footerLengthPosition < 0)

        goto exit;

    if (fsetpos(bundle, &footerLengthPosition))

        goto exit;

    UInt32 footerLength = 0;

    if (fread(&footerLength, 4, 1, bundle) != 1) {

        LOG_ERROR("Failed to read ResumeData length from the bundle - errno(%i)", errno);  

        goto exit;

    }

    // Make sure theres enough bytes to read in for the resume data, and perform the read

    fpos_t footerStartPosition = fileStat.st_size - 8 - footerLength;

    ASSERT(footerStartPosition >= 0);

    if (footerStartPosition < 0)

        goto exit;

    if (fsetpos(bundle, &footerStartPosition))

        goto exit;

    footerBuffer.resize(footerLength);

    if (fread(footerBuffer.data(), 1, footerLength, bundle) != footerLength) {

        LOG_ERROR("Failed to read ResumeData from the bundle - errno(%i)", errno);  

        goto exit;

    }

    // CFURLDownload will seek to the appropriate place in the file (before our footer) and start overwriting from there

    // However, say we were within a few hundred bytes of the end of a download when it was paused -

    // The additional footer extended the length of the file beyond its final length, and there will be junk data leftover

    // at the end.  Therefore, now that we've retrieved the footer data, we need to truncate it.

    if (errno_t resizeError = _chsize_s(_fileno(bundle), footerStartPosition)) {

        LOG_ERROR("Failed to truncate the resume footer off the end of the file - errno(%i)", resizeError);

        goto exit;

    }

    // Finally, make the resume data.  Now, it is possible by some twist of fate the bundle magic number

    // was naturally at the end of the file and its not actually a valid bundle.  That, or someone engineered

    // it that way to try to attack us.  In that cause, this CFData will successfully create but when we 

    // actually try to start the CFURLDownload using this bogus data, it will fail and we will handle that gracefully

    result = CFDataCreate(0, footerBuffer.data(), footerLength);

exit:

    fclose(bundle);

    return result;

}

HRESULT WebDownload::appendResumeDataToBundle(CFDataRef resumeData, const String& bundlePath)

{

    if (!resumeData) {

        LOG_ERROR("Invalid resume data to write to bundle path");

        return E_FAIL;

    }

    if (bundlePath.isEmpty()) {

        LOG_ERROR("Cannot write resume data to empty download bundle path");

        return E_FAIL;

    }

    String nullifiedPath = bundlePath;

    FILE* bundle = 0;

    if (_wfopen_s(&bundle, nullifiedPath.charactersWithNullTermination(), TEXT("ab")) || !bundle) {

        LOG_ERROR("Failed to open file %s to append resume data", bundlePath.ascii().data());

        return E_FAIL;

    }

    HRESULT hr = E_FAIL;

    const UInt8* resumeBytes = CFDataGetBytePtr(resumeData);

    ASSERT(resumeBytes);

    if (!resumeBytes)

        goto exit;

    UInt32 resumeLength = CFDataGetLength(resumeData);

    ASSERT(resumeLength > 0);

    if (resumeLength < 1)

        goto exit;

    if (fwrite(resumeBytes, 1, resumeLength, bundle) != resumeLength) {

        LOG_ERROR("Failed to write resume data to the bundle - errno(%i)", errno);

        goto exit;

    }

    if (fwrite(&resumeLength, 4, 1, bundle) != 1) {

        LOG_ERROR("Failed to write footer length to the bundle - errno(%i)", errno);

        goto exit;

    }

    const UInt32& magic = bundleMagicNumber();

    if (fwrite(&magic, 4, 1, bundle) != 1) {

        LOG_ERROR("Failed to write footer magic number to the bundle - errno(%i)", errno);

        goto exit;

    }

    hr = S_OK;

exit:

    fclose(bundle);

    return hr;

}