/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Stuart Parmenter <pavlov@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "imgCache.h"

#include "ImageLogging.h"

#include "imgRequest.h"

#include "nsXPIDLString.h"
#include "nsCOMPtr.h"
#include "nsIServiceManager.h"
#include "nsIMemory.h"
#include "nsIObserverService.h"

#include "nsICache.h"
#include "nsICacheService.h"
#include "nsICacheSession.h"
#include "nsICacheEntryDescriptor.h"

#include "nsIFile.h"
#include "nsIFileURL.h"

NS_IMPL_ISUPPORTS3(imgCache, imgICache, nsIObserver, nsISupportsWeakReference)

imgCache::imgCache()
{
  /* member initializers and constructor code */
}

imgCache::~imgCache()
{
  /* destructor code */
}

nsresult imgCache::Init()
{
  nsresult rv;
  nsCOMPtr<nsIObserverService> os = do_GetService("@mozilla.org/observer-service;1", &rv);
  if (NS_FAILED(rv))
    return rv;
  
  imgCache* cache = new imgCache();
  if(!cache) return NS_ERROR_OUT_OF_MEMORY;

  os->AddObserver(cache, "memory-pressure", PR_FALSE);
  os->AddObserver(cache, "chrome-flush-skin-caches", PR_FALSE);
  os->AddObserver(cache, "chrome-flush-caches", PR_FALSE);

  return NS_OK;
}

/* void clearCache (in boolean chrome); */
NS_IMETHODIMP imgCache::ClearCache(PRBool chrome)
{
  if (chrome)
    return imgCache::ClearChromeImageCache();
  else
    return imgCache::ClearImageCache();
}


/* void removeEntry(in nsIURI uri); */
NS_IMETHODIMP imgCache::RemoveEntry(nsIURI *uri)
{
  if (imgCache::Remove(uri))
    return NS_OK;

  return NS_ERROR_NOT_AVAILABLE;
}

/* imgIRequest findEntry(in nsIURI uri); */
NS_IMETHODIMP imgCache::FindEntryProperties(nsIURI *uri, nsIProperties **_retval)
{
  PRBool expired;
  // This is an owning reference that must be released.
  imgRequest *request = nsnull;
  nsCOMPtr<nsICacheEntryDescriptor> entry;

  // addrefs request
  imgCache::Get(uri, &expired, &request, getter_AddRefs(entry));

  *_retval = nsnull;

  if (request) {
    *_retval = request->Properties();
    NS_ADDREF(*_retval);
  }

  NS_IF_RELEASE(request);

  return NS_OK;
}


static nsCOMPtr<nsICacheSession> gSession = nsnull;
static nsCOMPtr<nsICacheSession> gChromeSession = nsnull;

void GetCacheSession(nsIURI *aURI, nsICacheSession **_retval)
{
  NS_ASSERTION(aURI, "Null URI!");

  PRBool isChrome = PR_FALSE;
  aURI->SchemeIs("chrome", &isChrome);

  if (gSession && !isChrome) {
    *_retval = gSession;
    NS_ADDREF(*_retval);
    return;
  }

  if (gChromeSession && isChrome) {
    *_retval = gChromeSession;
    NS_ADDREF(*_retval);
    return;
  }

  nsCOMPtr<nsICacheService> cacheService(do_GetService("@mozilla.org/network/cache-service;1"));
  if (!cacheService) {
    NS_WARNING("Unable to get the cache service");
    return;
  }

  nsCOMPtr<nsICacheSession> newSession;
  cacheService->CreateSession(isChrome ? "image-chrome" : "image",
                              nsICache::STORE_IN_MEMORY,
                              nsICache::NOT_STREAM_BASED,
                              getter_AddRefs(newSession));

  if (!newSession) {
    NS_WARNING("Unable to create a cache session");
    return;
  }

  if (isChrome)
    gChromeSession = newSession;
  else {
    gSession = newSession;
    gSession->SetDoomEntriesIfExpired(PR_FALSE);
  }

  *_retval = newSession;
  NS_ADDREF(*_retval);
}


void imgCache::Shutdown()
{
  gSession = nsnull;
  gChromeSession = nsnull;
}


nsresult imgCache::ClearChromeImageCache()
{
  if (!gChromeSession)
    return NS_OK;

  return gChromeSession->EvictEntries();
}

nsresult imgCache::ClearImageCache()
{
  if (!gSession)
    return NS_OK;

  return gSession->EvictEntries();
}



PRBool imgCache::Put(nsIURI *aKey, imgRequest *request, nsICacheEntryDescriptor **aEntry)
{
  LOG_STATIC_FUNC(gImgLog, "imgCache::Put");

  nsresult rv;

  nsCOMPtr<nsICacheSession> ses;
  GetCacheSession(aKey, getter_AddRefs(ses));
  if (!ses) return PR_FALSE;

  nsCAutoString spec;
  aKey->GetAsciiSpec(spec);

  nsCOMPtr<nsICacheEntryDescriptor> entry;

  rv = ses->OpenCacheEntry(spec, nsICache::ACCESS_WRITE, nsICache::BLOCKING, getter_AddRefs(entry));

  if (NS_FAILED(rv) || !entry)
    return PR_FALSE;

  nsCOMPtr<nsISupports> sup = reinterpret_cast<nsISupports*>(request);
  entry->SetCacheElement(sup);

  entry->MarkValid();

  // If file, force revalidation on expiration
  PRBool isFile;
  aKey->SchemeIs("file", &isFile);
  if (isFile)
    entry->SetMetaDataElement("MustValidateIfExpired", "true");

  *aEntry = entry;
  NS_ADDREF(*aEntry);

  return PR_TRUE;
}

static PRUint32
SecondsFromPRTime(PRTime prTime)
{
  PRInt64 microSecondsPerSecond, intermediateResult;
  PRUint32 seconds;
  
  LL_I2L(microSecondsPerSecond, PR_USEC_PER_SEC);
  LL_DIV(intermediateResult, prTime, microSecondsPerSecond);
  LL_L2UI(seconds, intermediateResult);
  return seconds;
}


PRBool imgCache::Get(nsIURI *aKey, PRBool *aHasExpired, imgRequest **aRequest, nsICacheEntryDescriptor **aEntry)
{
  LOG_STATIC_FUNC(gImgLog, "imgCache::Get");

  nsresult rv;

  nsCOMPtr<nsICacheSession> ses;
  GetCacheSession(aKey, getter_AddRefs(ses));
  if (!ses) return PR_FALSE;

  nsCAutoString spec;
  aKey->GetAsciiSpec(spec);

  nsCOMPtr<nsICacheEntryDescriptor> entry;

  rv = ses->OpenCacheEntry(spec, nsICache::ACCESS_READ, nsICache::BLOCKING, getter_AddRefs(entry));

  if (NS_FAILED(rv) || !entry)
    return PR_FALSE;

  if (aHasExpired) {
    PRUint32 expirationTime;
    rv = entry->GetExpirationTime(&expirationTime);
    if (NS_FAILED(rv) || (expirationTime <= SecondsFromPRTime(PR_Now()))) {
      *aHasExpired = PR_TRUE;
    } else {
      *aHasExpired = PR_FALSE;
    }
    // Special treatment for file URLs - entry has expired if file has changed
    nsCOMPtr<nsIFileURL> fileUrl(do_QueryInterface(aKey));
    if (fileUrl) {
      PRUint32 lastModTime;
      entry->GetLastModified(&lastModTime);

      nsCOMPtr<nsIFile> theFile;
      rv = fileUrl->GetFile(getter_AddRefs(theFile));
      if (NS_SUCCEEDED(rv)) {
        PRInt64 fileLastMod;
        rv = theFile->GetLastModifiedTime(&fileLastMod);
        if (NS_SUCCEEDED(rv)) {
          // nsIFile uses millisec, NSPR usec
          PRInt64 one_thousand = LL_INIT(0, 1000);
          LL_MUL(fileLastMod, fileLastMod, one_thousand);
          *aHasExpired = SecondsFromPRTime((PRTime)fileLastMod) > lastModTime;
        }
      }
    }
  }

  nsCOMPtr<nsISupports> sup;
  entry->GetCacheElement(getter_AddRefs(sup));

  *aRequest = reinterpret_cast<imgRequest*>(sup.get());
  NS_IF_ADDREF(*aRequest);

  *aEntry = entry;
  NS_ADDREF(*aEntry);

  return PR_TRUE;
}


PRBool imgCache::Remove(nsIURI *aKey)
{
  LOG_STATIC_FUNC(gImgLog, "imgCache::Remove");
  if (!aKey) return PR_FALSE;

  nsresult rv;
  nsCOMPtr<nsICacheSession> ses;
  GetCacheSession(aKey, getter_AddRefs(ses));
  if (!ses) return PR_FALSE;

  nsCAutoString spec;
  aKey->GetAsciiSpec(spec);

  nsCOMPtr<nsICacheEntryDescriptor> entry;

  rv = ses->OpenCacheEntry(spec, nsICache::ACCESS_READ, nsICache::BLOCKING, getter_AddRefs(entry));

  if (NS_FAILED(rv) || !entry)
    return PR_FALSE;

  entry->Doom();

  return PR_TRUE;
}


NS_IMETHODIMP
imgCache::Observe(nsISupports* aSubject, const char* aTopic, const PRUnichar* aSomeData)
{
  if (strcmp(aTopic, "memory-pressure") == 0) {
    ClearCache(PR_FALSE);
    ClearCache(PR_TRUE);
  } else if (strcmp(aTopic, "chrome-flush-skin-caches") == 0 ||
             strcmp(aTopic, "chrome-flush-caches") == 0) {
    ClearCache(PR_TRUE);
  }
  return NS_OK;
}