Implement WEBGL_shared_resources

Source/core/html/canvas/WebGLSharedObject.cpp

Index: Source/core/html/canvas/WebGLSharedObject.cpp
diff --git a/Source/core/html/canvas/WebGLSharedObject.cpp b/Source/core/html/canvas/WebGLSharedObject.cpp
index f5d63651ff51b90d8b53a0cebd5009cb176f1560..34b89edf18eda75f9e564018cced9bfd091ad53f 100644
--- a/Source/core/html/canvas/WebGLSharedObject.cpp
+++ b/Source/core/html/canvas/WebGLSharedObject.cpp
@@ -27,21 +27,29 @@
 
 #include "core/html/canvas/WebGLSharedObject.h"
 
+#include "core/html/canvas/WebGLAcquireSharedResourceCallback.h"
 #include "core/html/canvas/WebGLContextGroup.h"
 #include "core/html/canvas/WebGLRenderingContext.h"
 
 namespace WebCore {
 
 WebGLSharedObject::WebGLSharedObject(WebGLRenderingContext* context)
-    : WebGLObject(context),
-      m_contextGroup(context->contextGroup())
+    : WebGLObject(context)
+    , m_contextGroup(context->contextGroup())
+    , m_acquireMode(WebGLSharedObject::Unacquired)
 {
+    bool success = acquire(WebGLSharedObject::Exclusive, context);
+    ASSERT(success);
+
+    // We need to mark shaders and programs as bound as there is no way to easy way to bind/attach them.
+    markAsBoundSinceLastAcquireForContext(context);
 }
 
 WebGLSharedObject::~WebGLSharedObject()
 {
-    if (m_contextGroup)
+    if (m_contextGroup) {
         m_contextGroup->removeObject(this);
+    }
 }
 
 void WebGLSharedObject::detachContextGroup()
@@ -59,4 +67,289 @@ GraphicsContext3D* WebGLSharedObject::getAGraphicsContext3D() const
     return m_contextGroup ? m_contextGroup->getAGraphicsContext3D() : 0;
 }
 
+bool WebGLSharedObject::isAcquiredForContext(const WebGLRenderingContext* context, WebGLSharedObject::AcquireMode neededMode, bool mustBeBoundSinceLastAcquire, bool* hasBeenBoundSinceLastAcquire, const char** reason) const
+{
+    AcquireContextMap::const_iterator it = m_acquireContextMap.find(context);
+    if (it == m_acquireContextMap.end()) {
+        *reason = " not acquired in this context";
+        return false;
+    }
+
+    bool sameMode = m_acquireMode == neededMode;
+    bool validCombo = m_acquireMode == WebGLSharedObject::Exclusive && neededMode == WebGLSharedObject::ReadOnly;
+    if (!sameMode && !validCombo) {
+        *reason = " not acquired for exclusive access";
+        return false;
+    }
+
+    if (mustBeBoundSinceLastAcquire && !it->value) {
+        *reason = " has not been bound since last acquired";
+        return false;
+    }
+
+    if (hasBeenBoundSinceLastAcquire) {
+        *hasBeenBoundSinceLastAcquire = it->value;
+    }
+
+    return true;
+}
+
+bool WebGLSharedObject::validate(const char* functionName, WebGLRenderingContext* context, WebGLSharedObject::AcquireMode neededMode, bool mustBeBoundSinceLastAcquire, bool* boundSinceLastAcquire) const
+{
+    if (context->contextGroup() != m_contextGroup) {
+        String msg(String(typeName()) + " not from this share group");
+        context->synthesizeGLError(GraphicsContext3D::INVALID_OPERATION, functionName, msg.utf8().data());
+        return false;
+    }
+
+    const char* reason;
+    if (!isAcquiredForContext(context, neededMode, mustBeBoundSinceLastAcquire, boundSinceLastAcquire, &reason)) {
+        String msg(String(typeName()) + reason);
+        context->synthesizeGLError(GraphicsContext3D::INVALID_OPERATION, functionName, msg.utf8().data());
+        return false;
+    }
+
+    return true;
+}
+
+void WebGLSharedObject::markAsBoundSinceLastAcquireForContext(const WebGLRenderingContext* context)
+{
+    AcquireContextMap::iterator it = m_acquireContextMap.find(context);
+    ASSERT(it != m_acquireContextMap.end());
+    it->value = true;
+}
+
+bool WebGLSharedObject::acquire(WebGLSharedObject::AcquireMode desiredMode, const WebGLRenderingContext* context)
+{
+    AcquireContextMap::const_iterator it = m_acquireContextMap.find(context);
+    if (it != m_acquireContextMap.end()) {
+        // How can I get here?
+        return false;
+    }
+
+    bool unacquired = m_acquireMode == WebGLSharedObject::Unacquired;
+    bool bothReadOnly = m_acquireMode == WebGLSharedObject::ReadOnly && desiredMode == WebGLSharedObject::ReadOnly;
+    if (!unacquired && !bothReadOnly) {
+        return false;
+    }
+
+    // Note: The resource is acquired at this point. The user may still cancel
+    // the request though before it the acquire callback is fired. If it is
+    // cancelled the cancel acts as a call to release.
+    m_acquireMode = desiredMode;
+    m_acquireContextMap.add(context, false);
+    return true;
+}
+
+bool WebGLSharedObject::addAcquireRequest(WebGLRenderingContext* context, WebGLSharedObject::AcquireMode desiredMode, PassRefPtr<WebGLAcquireSharedResourceCallback> callback, long& id)
+{
+    switch (desiredMode) {
+    case WebGLSharedObject::ReadOnly:
+    case WebGLSharedObject::Exclusive:
+        break;
+    default:
+        context->synthesizeGLError(GraphicsContext3D::INVALID_ENUM, "acquireSharedResource", "mode is not READ_ONLY or EXCLUSIVE");
+        return false;
+    }
+
+    // Checks the object belongs to this group.
+    // Note: We let lost objects go through here.
+    if (context->contextGroup() != m_contextGroup && !isLost()) {
+        context->synthesizeGLError(GraphicsContext3D::INVALID_OPERATION, "acquireSharedResource", "object is not from this ShareGroup");
+        return false;
+    }
+
+    // Checks it is not already acquired by this context.
+    AcquireContextMap::iterator it = m_acquireContextMap.find(context);
+    if (it != m_acquireContextMap.end()) {
+        context->synthesizeGLError(GraphicsContext3D::INVALID_OPERATION, "acquireSharedResource", "object is already acquired in this context");
+        return false;
+    }
+
+    // Checks it is not already in one of the queues.
+    if (isRequestPending(context)) {
+        context->synthesizeGLError(GraphicsContext3D::INVALID_OPERATION, "acquireSharedResource", "request to acquire this object is already pending in this context");
+        return false;
+    }
+
+    // Adds the request.
+    id = generateAcquireRequestId();
+    m_acquireRequestQueue.append(WebGLAcquireSharedResourceRequest::create(this, callback, desiredMode, context, id));
+    processAcquireRequests();
+    return true;
+}
+
+bool WebGLSharedObject::release(WebGLRenderingContext* context)
+{
+    AcquireContextMap::iterator it = m_acquireContextMap.find(context);
+    if (it == m_acquireContextMap.end()) {
+        return false;
+    }
+
+    m_acquireContextMap.remove(it);
+    if (m_acquireContextMap.isEmpty()) {
+        if (m_acquireMode == WebGLSharedObject::Exclusive) {
+            // TODO: Use flush if on top of virtual contexts (maybe we should have an extension GL_CHROMIUM_flush_sync to mark that only flush is needed)
+            //       Use sync objects/fences if available.
+            //       Use glFinish otherwise.
+            context->flush(); // Using flush for now. So far only certain Android devices need a finish.
+        }
+        m_acquireMode = WebGLSharedObject::Unacquired;
+        processAcquireRequests();
+    }
+
+    return true;
+}
+
+void WebGLSharedObject::processAcquireRequests()
+{
+    // Queue all the events that could succeed right now.
+    while (!m_acquireRequestQueue.isEmpty()) {
+        RefPtr<WebGLAcquireSharedResourceRequest> request = m_acquireRequestQueue.first();
+        if (!acquire(request->acquireMode(), request->context())) {
+            break;
+        }
+
+        m_acquireRequestQueue.removeFirst();
+        m_acquireRequestPostedList.append(request);
+
+        // queue event
+        ScriptExecutionContext* scriptExecutionContext = request->context()->scriptExecutionContext();
+        if (scriptExecutionContext) {
+            scriptExecutionContext->postTask(adoptPtr(new DispatchCallbackTask(request)));
+        }
+    }
+}
+
+bool WebGLSharedObject::isRequestPending(const WebGLRenderingContext* context)
+{
+    for (AcquireRequestQueue::iterator it = m_acquireRequestQueue.begin(); it != m_acquireRequestQueue.end(); ++it) {
+        if ((*it)->context() == context) {
+            return true;
+        }
+    }
+    for (AcquireRequestList::iterator it = m_acquireRequestPostedList.begin(); it != m_acquireRequestPostedList.end(); ++it) {
+        if ((*it)->context() == context) {
+            return true;
+        }
+    }
+    return false;
+}
+
+bool WebGLSharedObject::cancelAcquireRequest(const WebGLRenderingContext* context, long id)
+{
+    for (AcquireRequestQueue::iterator it = m_acquireRequestQueue.begin(); it != m_acquireRequestQueue.end(); ++it) {
+        if ((*it)->id() == id) {
+            // Only remove it if it's from this context.
+            if ((*it)->context() == context) {
+                (*it)->cancel();
+                m_acquireRequestQueue.remove(it);
+                processAcquireRequests();
+            }
+            return true;
+        }
+    }
+    for (AcquireRequestList::iterator it = m_acquireRequestPostedList.begin(); it != m_acquireRequestPostedList.end(); ++it) {
+        if ((*it)->id() == id) {
+            // Only remove it if it's from this context.
+            if ((*it)->context() == context) {
+                (*it)->cancel();
+                m_acquireRequestPostedList.remove(it);
+                processAcquireRequests();
+            }
+            return true;
+        }
+    }
+    return false;
+}
+
+void WebGLSharedObject::cancelAllPendingRequestsForContext(const WebGLRenderingContext* context)
+{
+    bool done = false;
+    while (!done) {
+        done = true;
+        for (AcquireRequestQueue::iterator it = m_acquireRequestQueue.begin(); it != m_acquireRequestQueue.end(); ++it) {
+            if ((*it)->context() == context) {
+                cancelAcquireRequest(context, (*it)->id());
+                done = false;
+                break;
+            }
+        }
+    }
+
+    done = false;
+    while (!done) {
+        done = true;
+        for (AcquireRequestList::iterator it = m_acquireRequestPostedList.begin(); it != m_acquireRequestPostedList.end(); ++it) {
+            if ((*it)->context() == context) {
+                cancelAcquireRequest(context, (*it)->id());
+                done = false;
+                break;
+            }
+        }
+    }
+}
+
+void WebGLSharedObject::removePostedAcquireRequest(const WebGLRenderingContext* context, long id)
+{
+    for (AcquireRequestList::iterator it = m_acquireRequestPostedList.begin(); it != m_acquireRequestPostedList.end(); ++it) {
+        if ((*it)->id() == id) {
+            ASSERT((*it)->context() == context);
+            m_acquireRequestPostedList.remove(it);
+            return;
+        }
+    }
+    ASSERT(false); // should never get here.
+}
+
+int WebGLSharedObject::generateAcquireRequestId()
+{
+    AtomicallyInitializedStatic(int, acquireRequestId = 0);
+    return atomicIncrement(&acquireRequestId);
+}
+
+WebGLSharedObject::DispatchCallbackTask::~DispatchCallbackTask()
+{
+}
+
+void WebGLSharedObject::DispatchCallbackTask::performTask(ScriptExecutionContext*)
+{
+    m_request->run();
+}
+
+WebGLAcquireSharedResourceRequest::WebGLAcquireSharedResourceRequest(PassRefPtr<WebGLSharedObject> sharedObject, PassRefPtr<WebGLAcquireSharedResourceCallback> callback, WebGLSharedObject::AcquireMode acquireMode, WebGLRenderingContext* context, long id)
+    : m_sharedObject(sharedObject)
+    , m_context(context)
+    , m_id(id)
+    , m_acquireMode(acquireMode)
+    , m_callback(callback)
+{
+}
+
+WebGLAcquireSharedResourceRequest::~WebGLAcquireSharedResourceRequest()
+{
 }
+
+PassRefPtr<WebGLAcquireSharedResourceRequest> WebGLAcquireSharedResourceRequest::create(PassRefPtr<WebGLSharedObject> sharedObject, PassRefPtr<WebGLAcquireSharedResourceCallback> callback, WebGLSharedObject::AcquireMode acquireMode, WebGLRenderingContext* context, long id)
+{
+    return adoptRef(new WebGLAcquireSharedResourceRequest(sharedObject, callback, acquireMode, context, id));
+}
+
+void WebGLAcquireSharedResourceRequest::cancel()
+{
+    m_acquireMode = WebGLSharedObject::Unacquired;
+    m_callback.clear();
+}
+
+void WebGLAcquireSharedResourceRequest::run()
+{
+    if (m_callback) {
+        RefPtr<WebGLAcquireSharedResourceRequest> self(this); // Need to keep a reference to ourselves as the next line may remove our last reference.
+        m_sharedObject->removePostedAcquireRequest(context(), id());
+        m_callback->handleEvent();
+        m_callback.clear();
+    }
+}
+
+} // namespace WebCore
+