/*

    This file is part of the KDE libraries

    Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)

    Copyright (C) 2001 Dirk Mueller (mueller@kde.org)

    Copyright (C) 2002 Waldo Bastian (bastian@kde.org)

    Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License

    along with this library; see the file COPYING.LIB.  If not, write to

    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

    Boston, MA 02110-1301, USA.

    This class provides all functionality needed for loading images, style sheets and html

    pages from the web. It has a memory cache for these objects.

*/

#include "config.h"

#include "DocLoader.h"

#include "Cache.h"

#include "CachedCSSStyleSheet.h"

#include "CachedImage.h"

#include "CachedScript.h"

#include "CachedXSLStyleSheet.h"

#include "Document.h"

#include "Frame.h"

#include "FrameLoader.h"

#include "loader.h"

namespace WebCore {

DocLoader::DocLoader(Frame *frame, Document* doc)

    : m_cache(cache())

    , m_cachePolicy(CachePolicyVerify)

    , m_frame(frame)

    , m_doc(doc)

    , m_requestCount(0)

    , m_autoLoadImages(true)

    , m_loadInProgress(false)

    , m_allowStaleResources(false)

{

    m_cache->addDocLoader(this);

}

DocLoader::~DocLoader()

{

#if PRELOAD_SCANNER_ENABLED

    clearPreloads();

#endif

    HashMap<String, CachedResource*>::iterator end = m_docResources.end();

    for (HashMap<String, CachedResource*>::iterator it = m_docResources.begin(); it != end; ++it)

        it->second->setDocLoader(0);

    m_cache->removeDocLoader(this);

}

void DocLoader::checkForReload(const KURL& fullURL)

{

    if (m_allowStaleResources)

        return; //Don't reload resources while pasting

    if (m_cachePolicy == CachePolicyVerify) {

       if (!m_reloadedURLs.contains(fullURL.url())) {

          CachedResource* existing = cache()->resourceForURL(fullURL.url());

#if PRELOAD_SCANNER_ENABLED

          if (existing && existing->isExpired() && !existing->isPreloaded()) {

#else

          if (existing && existing->isExpired()) {

#endif

             cache()->remove(existing);

             m_reloadedURLs.add(fullURL.url());

          }

       }

    } else if ((m_cachePolicy == CachePolicyReload) || (m_cachePolicy == CachePolicyRefresh)) {

       if (!m_reloadedURLs.contains(fullURL.url())) {

          CachedResource* existing = cache()->resourceForURL(fullURL.url());

#if PRELOAD_SCANNER_ENABLED

           if (existing && !existing->isPreloaded()) {

#else

          if (existing)

#endif

             cache()->remove(existing);

          m_reloadedURLs.add(fullURL.url());

#if PRELOAD_SCANNER_ENABLED

       }

#endif

       }

    }

}

CachedImage* DocLoader::requestImage(const String& url)

{

    CachedImage* resource = static_cast<CachedImage*>(requestResource(CachedResource::ImageResource, url));

    if (autoLoadImages() && resource && resource->stillNeedsLoad()) {

        resource->setLoading(true);

        cache()->loader()->load(this, resource, true);

    }

    return resource;

}

CachedCSSStyleSheet* DocLoader::requestCSSStyleSheet(const String& url, const String& charset, bool isUserStyleSheet)

{

    // FIXME: Passing true for "skipCanLoadCheck" here in the isUserStyleSheet case  won't have any effect

    // if this resource is already in the cache. It's theoretically possible that what's in the cache already

    // is a load that failed because of the canLoad check. Probably not an issue in practice.

    CachedCSSStyleSheet *sheet = static_cast<CachedCSSStyleSheet*>(requestResource(CachedResource::CSSStyleSheet, url, &charset, isUserStyleSheet, !isUserStyleSheet));

    // A user style sheet can outlive its DocLoader so don't store any pointers to it

    if (sheet && isUserStyleSheet) {

        sheet->setDocLoader(0);

        m_docResources.remove(sheet->url());

    }

    return sheet;

}

CachedCSSStyleSheet* DocLoader::requestUserCSSStyleSheet(const String& url, const String& charset)

{

    return requestCSSStyleSheet(url, charset, true);

}

CachedScript* DocLoader::requestScript(const String& url, const String& charset)

{

    return static_cast<CachedScript*>(requestResource(CachedResource::Script, url, &charset));

}

#if ENABLE(XSLT)

CachedXSLStyleSheet* DocLoader::requestXSLStyleSheet(const String& url)

{

    return static_cast<CachedXSLStyleSheet*>(requestResource(CachedResource::XSLStyleSheet, url));

}

#endif

#if ENABLE(XBL)

CachedXBLDocument* DocLoader::requestXBLDocument(const String& url)

{

    return static_cast<CachedXSLStyleSheet*>(requestResource(CachedResource::XBL, url));

}

#endif

#if PRELOAD_SCANNER_ENABLED

CachedResource* DocLoader::requestResource(CachedResource::Type type, const String& url, const String* charset, bool skipCanLoadCheck, bool sendResourceLoadCallbacks, bool isPreload)

#else

CachedResource* DocLoader::requestResource(CachedResource::Type type, const String& url, const String* charset, bool skipCanLoadCheck, bool sendResourceLoadCallbacks)

#endif

{

    KURL fullURL = m_doc->completeURL(url.deprecatedString());

    if (cache()->disabled()) {

        HashMap<String, CachedResource*>::iterator it = m_docResources.find(fullURL.url());

        if (it != m_docResources.end()) {

            it->second->setDocLoader(0);

            m_docResources.remove(it);

        }

    }

    if (m_frame && m_frame->loader()->isReloading())

        setCachePolicy(CachePolicyReload);

    checkForReload(fullURL);

#if PRELOAD_SCANNER_ENABLED

    CachedResource* resource = cache()->requestResource(this, type, fullURL, charset, skipCanLoadCheck, sendResourceLoadCallbacks, isPreload);

#else

    CachedResource* resource = cache()->requestResource(this, type, fullURL, charset, skipCanLoadCheck, sendResourceLoadCallbacks);

#endif

    if (resource) {

        m_docResources.set(resource->url(), resource);

        checkCacheObjectStatus(resource);

    }

    return resource;

}

void DocLoader::setAutoLoadImages(bool enable)

{

    if (enable == m_autoLoadImages)

        return;

    m_autoLoadImages = enable;

    if (!m_autoLoadImages)

        return;

    HashMap<String, CachedResource*>::iterator end = m_docResources.end();

    for (HashMap<String, CachedResource*>::iterator it = m_docResources.begin(); it != end; ++it) {

        CachedResource* resource = it->second;

        if (resource->type() == CachedResource::ImageResource) {

            CachedImage* image = const_cast<CachedImage*>(static_cast<const CachedImage *>(resource));

            CachedResource::Status status = image->status();

            if (status != CachedResource::Unknown)

                continue;

            cache()->loader()->load(this, image, true);

        }

    }

}

void DocLoader::setCachePolicy(CachePolicy cachePolicy)

{

    m_cachePolicy = cachePolicy;

}

void DocLoader::removeCachedResource(CachedResource* resource) const

{

    m_docResources.remove(resource->url());

}

void DocLoader::setLoadInProgress(bool load)

{

    m_loadInProgress = load;

    if (!load && m_frame)

        m_frame->loader()->loadDone();

}

void DocLoader::checkCacheObjectStatus(CachedResource* resource)

{

    // Return from the function for objects that we didn't load from the cache.

    if (!resource)

        return;

    switch (resource->status()) {

        case CachedResource::Cached:

            break;

        case CachedResource::NotCached:

        case CachedResource::Unknown:

        case CachedResource::New:

        case CachedResource::Pending:

            return;

    }

    // Notify the caller that we "loaded".

    if (!m_frame || m_frame->loader()->haveToldBridgeAboutLoad(resource->url()))

        return;

    ResourceRequest request(resource->url());

    const ResourceResponse& response = resource->response();

    SharedBuffer* data = resource->data();

    if (resource->sendResourceLoadCallbacks()) {

        // FIXME: If the WebKit client changes or cancels the request, WebCore does not respect this and continues the load.

        m_frame->loader()->loadedResourceFromMemoryCache(request, response, data ? data->size() : 0);

    }

    m_frame->loader()->didTellBridgeAboutLoad(resource->url());

}

void DocLoader::incrementRequestCount()

{

    ++m_requestCount;

}

void DocLoader::decrementRequestCount()

{

    --m_requestCount;

    ASSERT(m_requestCount > -1);

}

int DocLoader::requestCount()

{

    if (loadInProgress())

         return m_requestCount + 1;

    return m_requestCount;

}

#if PRELOAD_SCANNER_ENABLED

#define PRELOAD_DEBUG 0

void DocLoader::preload(CachedResource::Type type, const String& url)

{

    String encoding = (type == CachedResource::Script || type == CachedResource::CSSStyleSheet) ? m_doc->frame()->loader()->encoding() : String();

    CachedResource* resource = requestResource(type, url, &encoding, true);

    if (!resource || m_preloads.contains(resource))

        return;

    resource->increasePreloadCount();

    m_preloads.add(resource);

#if PRELOAD_DEBUG

    printf("PRELOADING %s\n",  resource->url().latin1().data());

#endif

}

void DocLoader::clearPreloads()

{

#if PRELOAD_DEBUG

    printPreloadStats();

#endif

    ListHashSet<CachedResource*>::iterator end = m_preloads.end();

    for (ListHashSet<CachedResource*>::iterator it = m_preloads.begin(); it != end; ++it) {

        CachedResource* res = *it;

            cache()->remove(res);

        res->decreasePreloadCount();

    }

    m_preloads.clear();

}

#if PRELOAD_DEBUG

void DocLoader::printPreloadStats()

{

    unsigned scripts = 0;

    unsigned scriptMisses = 0;

    unsigned stylesheets = 0;

    unsigned stylesheetMisses = 0;

    unsigned images = 0;

    unsigned imageMisses = 0;

    ListHashSet<CachedResource*>::iterator end = m_preloads.end();

    for (ListHashSet<CachedResource*>::iterator it = m_preloads.begin(); it != end; ++it) {

        CachedResource* res = *it;

        if (res->preloadResult() == CachedResource::PreloadNotReferenced)

            printf("!! UNREFERENCED PRELOAD %s\n", res->url().latin1().data());

        else if (res->preloadResult() == CachedResource::PreloadReferencedWhileComplete)

            printf("HIT COMPLETE PRELOAD %s\n", res->url().latin1().data());

        else if (res->preloadResult() == CachedResource::PreloadReferencedWhileLoading)

            printf("HIT LOADING PRELOAD %s\n", res->url().latin1().data());

        if (res->type() == CachedResource::Script) {

            scripts++;

            if (res->preloadResult() < CachedResource::PreloadReferencedWhileLoading)

                scriptMisses++;

        } else if (res->type() == CachedResource::CSSStyleSheet) {

            stylesheets++;

            if (res->preloadResult() < CachedResource::PreloadReferencedWhileLoading)

                stylesheetMisses++;

        } else {

            images++;

            if (res->preloadResult() < CachedResource::PreloadReferencedWhileLoading)

                imageMisses++;

        }

        if (res->errorOccurred())

            cache()->remove(res);

        res->decreasePreloadCount();

    }

    m_preloads.clear();

    if (scripts)

        printf("SCRIPTS: %d (%d hits, hit rate %d%%)\n", scripts, scripts - scriptMisses, (scripts - scriptMisses) * 100 / scripts);

    if (stylesheets)

        printf("STYLESHEETS: %d (%d hits, hit rate %d%%)\n", stylesheets, stylesheets - stylesheetMisses, (stylesheets - stylesheetMisses) * 100 / stylesheets);

    if (images)

        printf("IMAGES:  %d (%d hits, hit rate %d%%)\n", images, images - imageMisses, (images - imageMisses) * 100 / images);

}

#endif

#endif

}