C++ StartupCache类代码示例

// We have data if we're in the middle of writing it or we already
// have it in the cache.
nsresult
nsXULPrototypeCache::HasData(nsIURI* uri, bool* exists)
{
    if (mOutputStreamTable.Get(uri, nullptr)) {
        *exists = true;
        return NS_OK;
    }
    nsAutoCString spec(kXULCachePrefix);
    nsresult rv = PathifyURI(uri, spec);
    if (NS_FAILED(rv)) {
        *exists = false;
        return NS_OK;
    }
    nsAutoArrayPtr<char> buf;
    uint32_t len;
    StartupCache* sc = StartupCache::GetSingleton();
    if (sc)
        rv = sc->GetBuffer(spec.get(), getter_Transfers(buf), &len);
    else {
        *exists = false;
        return NS_OK;
    }
    *exists = NS_SUCCEEDED(rv);
    return NS_OK;
}

// We have data if we're in the middle of writing it or we already
// have it in the cache.
nsresult
nsXULPrototypeCache::HasData(nsIURI* uri, bool* exists)
{
    if (mOutputStreamTable.Get(uri, nsnull)) {
        *exists = true;
        return NS_OK;
    }
    nsCAutoString spec(kXULCachePrefix);
    nsresult rv = PathifyURI(uri, spec);
    if (NS_FAILED(rv)) {
        *exists = false;
        return NS_OK;
    }
    nsAutoArrayPtr<char> buf;
    PRUint32 len;
    if (gStartupCache)
        rv = gStartupCache->GetBuffer(spec.get(), getter_Transfers(buf), 
                                      &len);
    else {
        // We don't have everything we need to call BeginCaching and set up
        // gStartupCache right now, but we just need to check the cache for 
        // this URI.
        StartupCache* sc = StartupCache::GetSingleton();
        if (!sc) {
            *exists = false;
            return NS_OK;
        }
        rv = sc->GetBuffer(spec.get(), getter_Transfers(buf), &len);
    }
    *exists = NS_SUCCEEDED(rv);
    return NS_OK;
}

nsresult
StartupCacheWrapper::PutBuffer(const char* id, const char* inbuf, uint32_t length) 
{
  StartupCache* sc = StartupCache::GetSingleton();
  if (!sc) {
    return NS_ERROR_NOT_INITIALIZED;
  }
  return sc->PutBuffer(id, inbuf, length);
}

nsresult 
StartupCacheWrapper::GetBuffer(const char* id, char** outbuf, uint32_t* length) 
{
  StartupCache* sc = StartupCache::GetSingleton();
  if (!sc) {
    return NS_ERROR_NOT_INITIALIZED;
  }
  UniquePtr<char[]> buf;
  nsresult rv = sc->GetBuffer(id, &buf, length);
  *outbuf = buf.release();
  return rv;
}

void
StartupCache::ThreadedWrite(void *aClosure)
{
  PR_SetCurrentThreadName("StartupCache");
  /*
   * It is safe to use the pointer passed in aClosure to reference the
   * StartupCache object because the thread's lifetime is tightly coupled to
   * the lifetime of the StartupCache object; this thread is joined in the
   * StartupCache destructor, guaranteeing that this function runs if and only
   * if the StartupCache object is valid.
   */
  StartupCache* startupCacheObj = static_cast<StartupCache*>(aClosure);
  startupCacheObj->WriteToDisk();
}

nsresult
StartupCacheListener::Observe(nsISupports *subject, const char* topic, const char16_t* data)
{
  StartupCache* sc = StartupCache::GetSingleton();
  if (!sc)
    return NS_OK;

  if (strcmp(topic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
    // Do not leave the thread running past xpcom shutdown
    sc->WaitOnWriteThread();
    StartupCache::gShutdownInitiated = true;
  } else if (strcmp(topic, "startupcache-invalidate") == 0) {
    sc->InvalidateCache();
  }
  return NS_OK;
} 

nsresult
nsXULPrototypeCache::FinishOutputStream(nsIURI* uri) 
{
    nsresult rv;
    StartupCache* sc = StartupCache::GetSingleton();
    if (!sc)
        return NS_ERROR_NOT_AVAILABLE;

    nsCOMPtr<nsIStorageStream> storageStream;
    bool found = mOutputStreamTable.Get(uri, getter_AddRefs(storageStream));
    if (!found)
        return NS_ERROR_UNEXPECTED;
    nsCOMPtr<nsIOutputStream> outputStream
        = do_QueryInterface(storageStream);
    outputStream->Close();
    
    nsAutoArrayPtr<char> buf;
    uint32_t len;
    rv = NewBufferFromStorageStream(storageStream, getter_Transfers(buf), 
                                    &len);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!mCacheURITable.GetEntry(uri)) {
        nsAutoCString spec(kXULCachePrefix);
        rv = PathifyURI(uri, spec);
        if (NS_FAILED(rv))
            return NS_ERROR_NOT_AVAILABLE;
        rv = sc->PutBuffer(spec.get(), buf, len);
        if (NS_SUCCEEDED(rv)) {
            mOutputStreamTable.Remove(uri);
            mCacheURITable.RemoveEntry(uri);
        }
    }

    return rv;
}

NS_EXPORT nsresult
NewObjectOutputWrappedStorageStream(nsIObjectOutputStream **wrapperStream,
                                    nsIStorageStream** stream,
                                    bool wantDebugStream)
{
  nsCOMPtr<nsIStorageStream> storageStream;

  nsresult rv = NS_NewStorageStream(256, PR_UINT32_MAX, getter_AddRefs(storageStream));
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIObjectOutputStream> objectOutput
    = do_CreateInstance("@mozilla.org/binaryoutputstream;1");
  nsCOMPtr<nsIOutputStream> outputStream
    = do_QueryInterface(storageStream);
  
  objectOutput->SetOutputStream(outputStream);
  
#ifdef DEBUG
  if (wantDebugStream) {
    // Wrap in debug stream to detect unsupported writes of 
    // multiply-referenced non-singleton objects
    StartupCache* sc = StartupCache::GetSingleton();
    NS_ENSURE_TRUE(sc, NS_ERROR_UNEXPECTED);
    nsCOMPtr<nsIObjectOutputStream> debugStream;
    sc->GetDebugObjectOutputStream(objectOutput, getter_AddRefs(debugStream));
    debugStream.forget(wrapperStream);
  } else {
    objectOutput.forget(wrapperStream);
  }
#else
  objectOutput.forget(wrapperStream);
#endif
  
  storageStream.forget(stream);
  return NS_OK;
}

nsresult
nsXULPrototypeCache::BeginCaching(nsIURI* aURI)
{
    nsresult rv, tmp;

    nsAutoCString path;
    aURI->GetPath(path);
    if (!StringEndsWith(path, NS_LITERAL_CSTRING(".xul")))
        return NS_ERROR_NOT_AVAILABLE;

    StartupCache* startupCache = StartupCache::GetSingleton();
    if (!startupCache)
        return NS_ERROR_FAILURE;

    if (gDisableXULCache)
        return NS_ERROR_NOT_AVAILABLE;

    // Get the chrome directory to validate against the one stored in the
    // cache file, or to store there if we're generating a new file.
    nsCOMPtr<nsIFile> chromeDir;
    rv = NS_GetSpecialDirectory(NS_APP_CHROME_DIR, getter_AddRefs(chromeDir));
    if (NS_FAILED(rv))
        return rv;
    nsAutoCString chromePath;
    rv = chromeDir->GetNativePath(chromePath);
    if (NS_FAILED(rv))
        return rv;

    // XXXbe we assume the first package's locale is the same as the locale of
    // all subsequent packages of cached chrome URIs....
    nsAutoCString package;
    rv = aURI->GetHost(package);
    if (NS_FAILED(rv))
        return rv;
    nsCOMPtr<nsIXULChromeRegistry> chromeReg
        = do_GetService(NS_CHROMEREGISTRY_CONTRACTID, &rv);
    nsAutoCString locale;
    rv = chromeReg->GetSelectedLocale(package, locale);
    if (NS_FAILED(rv))
        return rv;

    nsAutoCString fileChromePath, fileLocale;

    UniquePtr<char[]> buf;
    uint32_t len, amtRead;
    nsCOMPtr<nsIObjectInputStream> objectInput;

    rv = startupCache->GetBuffer(kXULCacheInfoKey, &buf, &len);
    if (NS_SUCCEEDED(rv))
        rv = NewObjectInputStreamFromBuffer(Move(buf), len,
                                            getter_AddRefs(objectInput));

    if (NS_SUCCEEDED(rv)) {
        rv = objectInput->ReadCString(fileLocale);
        tmp = objectInput->ReadCString(fileChromePath);
        if (NS_FAILED(tmp)) {
          rv = tmp;
        }
        if (NS_FAILED(rv) ||
            (!fileChromePath.Equals(chromePath) ||
             !fileLocale.Equals(locale))) {
            // Our cache won't be valid in this case, we'll need to rewrite.
            // XXX This blows away work that other consumers (like
            // mozJSComponentLoader) have done, need more fine-grained control.
            startupCache->InvalidateCache();
            mStartupCacheURITable.Clear();
            rv = NS_ERROR_UNEXPECTED;
        }
    } else if (rv != NS_ERROR_NOT_AVAILABLE)
        // NS_ERROR_NOT_AVAILABLE is normal, usually if there's no cachefile.
        return rv;

    if (NS_FAILED(rv)) {
        // Either the cache entry was invalid or it didn't exist, so write it now.
        nsCOMPtr<nsIObjectOutputStream> objectOutput;
        nsCOMPtr<nsIInputStream> inputStream;
        nsCOMPtr<nsIStorageStream> storageStream;
        rv = NewObjectOutputWrappedStorageStream(getter_AddRefs(objectOutput),
                                                 getter_AddRefs(storageStream),
                                                 false);
        if (NS_SUCCEEDED(rv)) {
            rv = objectOutput->WriteStringZ(locale.get());
            tmp = objectOutput->WriteStringZ(chromePath.get());
            if (NS_FAILED(tmp)) {
              rv = tmp;
            }
            tmp = objectOutput->Close();
            if (NS_FAILED(tmp)) {
              rv = tmp;
            }
            tmp = storageStream->NewInputStream(0, getter_AddRefs(inputStream));
            if (NS_FAILED(tmp)) {
              rv = tmp;
            }
        }

        if (NS_SUCCEEDED(rv)) {
            uint64_t len64;
            rv = inputStream->Available(&len64);
            if (NS_SUCCEEDED(rv)) {
//.........这里部分代码省略.........

nsresult
nsXULPrototypeCache::BeginCaching(nsIURI* aURI)
{
    nsresult rv;

    nsCAutoString path;
    aURI->GetPath(path);
    if (!StringEndsWith(path, NS_LITERAL_CSTRING(".xul")))
        return NS_ERROR_NOT_AVAILABLE;

    // Test gStartupCache to decide whether this is the first nsXULDocument
    // participating in the serialization.  If gStartupCache is non-null, this document
    // must not be first, but it can join the process.  Examples of
    // multiple master documents participating include hiddenWindow.xul and
    // navigator.xul on the Mac, and multiple-app-component (e.g., mailnews
    // and browser) startup due to command-line arguments.
    //
    if (gStartupCache) {
        mCacheURITable.Put(aURI, 1);

        return NS_OK;
    }

    // Use a local to refer to the service till we're sure we succeeded, then
    // commit to gStartupCache.
    StartupCache* startupCache = StartupCache::GetSingleton();
    if (!startupCache)
        return NS_ERROR_FAILURE;

    gDisableXULDiskCache =
        Preferences::GetBool(kDisableXULCachePref, gDisableXULDiskCache);

    Preferences::RegisterCallback(CachePrefChangedCallback,
                                  kDisableXULCachePref);

    if (gDisableXULDiskCache)
        return NS_ERROR_NOT_AVAILABLE;

    // Get the chrome directory to validate against the one stored in the
    // cache file, or to store there if we're generating a new file.
    nsCOMPtr<nsIFile> chromeDir;
    rv = NS_GetSpecialDirectory(NS_APP_CHROME_DIR, getter_AddRefs(chromeDir));
    if (NS_FAILED(rv))
        return rv;
    nsCAutoString chromePath;
    rv = chromeDir->GetNativePath(chromePath);
    if (NS_FAILED(rv))
        return rv;

    // XXXbe we assume the first package's locale is the same as the locale of
    // all subsequent packages of cached chrome URIs....
    nsCAutoString package;
    rv = aURI->GetHost(package);
    if (NS_FAILED(rv))
        return rv;
    nsCOMPtr<nsIXULChromeRegistry> chromeReg
        = do_GetService(NS_CHROMEREGISTRY_CONTRACTID, &rv);
    nsCAutoString locale;
    rv = chromeReg->GetSelectedLocale(package, locale);
    if (NS_FAILED(rv))
        return rv;

    nsCAutoString fileChromePath, fileLocale;
    
    nsAutoArrayPtr<char> buf;
    PRUint32 len, amtRead;
    nsCOMPtr<nsIObjectInputStream> objectInput;

    rv = startupCache->GetBuffer(kXULCacheInfoKey, getter_Transfers(buf), 
                                 &len);
    if (NS_SUCCEEDED(rv))
        rv = NewObjectInputStreamFromBuffer(buf, len, getter_AddRefs(objectInput));
    
    if (NS_SUCCEEDED(rv)) {
        buf.forget();
        rv = objectInput->ReadCString(fileLocale);
        rv |= objectInput->ReadCString(fileChromePath);
        if (NS_FAILED(rv) ||
            (!fileChromePath.Equals(chromePath) ||
             !fileLocale.Equals(locale))) {
            // Our cache won't be valid in this case, we'll need to rewrite.
            // XXX This blows away work that other consumers (like
            // mozJSComponentLoader) have done, need more fine-grained control.
            startupCache->InvalidateCache();
            rv = NS_ERROR_UNEXPECTED;
        }
    } else if (rv != NS_ERROR_NOT_AVAILABLE)
        // NS_ERROR_NOT_AVAILABLE is normal, usually if there's no cachefile.
        return rv;

    if (NS_FAILED(rv)) {
        // Either the cache entry was invalid or it didn't exist, so write it now.
        nsCOMPtr<nsIObjectOutputStream> objectOutput;
        nsCOMPtr<nsIInputStream> inputStream;
        nsCOMPtr<nsIStorageStream> storageStream;
        rv = NewObjectOutputWrappedStorageStream(getter_AddRefs(objectOutput),
                                                 getter_AddRefs(storageStream),
                                                 false);
        if (NS_SUCCEEDED(rv)) {
            rv = objectOutput->WriteStringZ(locale.get());
//.........这里部分代码省略.........