Source/modules/encryptedmedia/MediaKeys.cpp

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * 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
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#include "config.h"
#include "modules/encryptedmedia/MediaKeys.h"

#include "bindings/v8/ExceptionState.h"
#include "core/events/EventNames.h"
#include "core/html/HTMLMediaElement.h"
#include "core/platform/UUID.h"
#include "core/platform/graphics/ContentDecryptionModule.h"
#include "modules/encryptedmedia/MediaKeyMessageEvent.h"
#include "modules/encryptedmedia/MediaKeySession.h"
#include "wtf/HashSet.h"

namespace WebCore {

PassRefPtr<MediaKeys> MediaKeys::create(const String& keySystem, ExceptionState& es)
{
    // From <http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#dom-media-keys-constructor>:
    // The MediaKeys(keySystem) constructor must run the following steps:

    // 1. If keySystem is null or an empty string, throw an InvalidAccessError exception and abort these steps.
    if (keySystem.isEmpty()) {
        es.throwUninformativeAndGenericDOMException(InvalidAccessError);
        return 0;
    }

    // 2. If keySystem is not one of the user agent's supported Key Systems, throw a NotSupportedError and abort these steps.
    if (!ContentDecryptionModule::supportsKeySystem(keySystem)) {
        es.throwUninformativeAndGenericDOMException(NotSupportedError);
        return 0;
    }

    // 3. Let cdm be the content decryption module corresponding to keySystem.
    // 4. Load cdm if necessary.
    OwnPtr<ContentDecryptionModule> cdm = ContentDecryptionModule::create(keySystem);
    if (!cdm) {
        es.throwUninformativeAndGenericDOMException(NotSupportedError);
        return 0;
    }

    // 5. Create a new MediaKeys object.
    // 5.1 Let the keySystem attribute be keySystem.
    // 6. Return the new object to the caller.
    return adoptRef(new MediaKeys(keySystem, cdm.release()));
}

MediaKeys::MediaKeys(const String& keySystem, PassOwnPtr<ContentDecryptionModule> cdm)
    : m_mediaElement(0)
    , m_keySystem(keySystem)
    , m_cdm(cdm)
{
    ScriptWrappable::init(this);
}

MediaKeys::~MediaKeys()
{
    // From <http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#dom-media-keys-constructor>:
    // When destroying a MediaKeys object, follow the steps in close().
    for (size_t i = 0; i < m_sessions.size(); ++i)
        m_sessions[i]->close();
}

PassRefPtr<MediaKeySession> MediaKeys::createSession(ScriptExecutionContext* context, const String& type, Uint8Array* initData, ExceptionState& es)
{
    // From <http://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#dom-createsession>:
    // The createSession(type, initData) method must run the following steps:
    // Note: The contents of initData are container-specific Initialization Data.

    // 1. If type is null or an empty string and initData is not null or an empty string, throw an
    // InvalidAccessError exception and abort these steps.
    if ((type.isEmpty()) && (!initData || initData->length())) {
        es.throwUninformativeAndGenericDOMException(InvalidAccessError);
        return 0;
    }

    // 2. If type contains a MIME type that is not supported or is not supported by the keySystem, throw
    // a NotSupportedError exception and abort these steps.
    ASSERT(!type.isEmpty());
    if (type.isEmpty() || !m_cdm->supportsMIMEType(type)) {
        es.throwUninformativeAndGenericDOMException(NotSupportedError);
        return 0;
    }

    // 3. Create a new MediaKeySession object.
    RefPtr<MediaKeySession> session = MediaKeySession::create(context, m_cdm.get(), this);
    // 3.1 Let the keySystem attribute be keySystem.
    ASSERT(!session->keySystem().isEmpty());
    // 3.2 Let the sessionId attribute be a unique Session ID string. It may be generated by cdm.
    // This is handled by m_cdm and may happen asynchronously.

    // 4. Add the new object to an internal list of session objects.
    m_sessions.append(session);

    // 5. Schedule a task to generate a key request, providing type, initData, and the new object.
    session->generateKeyRequest(type, initData);

    // 6. Return the new object to the caller.
    return session;
}

void MediaKeys::setMediaElement(HTMLMediaElement* element)
{
    // FIXME: Cause HTMLMediaElement::setMediaKeys() to throw an exception if m_mediaElement is not 0.
    // FIXME: Hook up the CDM to the WebMediaPlayer in Chromium.
    ASSERT(!m_mediaElement);
    m_mediaElement = element;
}

}