private static NativeContinuation CaptureContinuation(Context cx, Interpreter.CallFrame frame, bool requireContinuationsTopFrame)
{
NativeContinuation c = new NativeContinuation();
ScriptRuntime.SetObjectProtoAndParent(c, ScriptRuntime.GetTopCallScope(cx));
// Make sure that all frames are frozen
Interpreter.CallFrame x = frame;
Interpreter.CallFrame outermost = frame;
while (x != null && !x.frozen)
{
x.frozen = true;
// Allow to GC unused stack space
for (int i = x.savedStackTop + 1; i != x.stack.Length; ++i)
{
// Allow to GC unused stack space
x.stack[i] = null;
x.stackAttributes[i] = ScriptableObject.EMPTY;
}
if (x.savedCallOp == Token.CALL)
{
// the call will always overwrite the stack top with the result
x.stack[x.savedStackTop] = null;
}
else
{
if (x.savedCallOp != Token.NEW)
{
Kit.CodeBug();
}
}
// the new operator uses stack top to store the constructed
// object so it shall not be cleared: see comments in
// setCallResult
outermost = x;
x = x.parentFrame;
}
if (requireContinuationsTopFrame)
{
while (outermost.parentFrame != null)
{
outermost = outermost.parentFrame;
}
if (!outermost.isContinuationsTopFrame)
{
throw new InvalidOperationException("Cannot capture continuation " + "from JavaScript code not called directly by " + "executeScriptWithContinuations or " + "callFunctionWithContinuations");
}
}
c.InitImplementation(frame);
return c;
}
internal ContinuationJump(NativeContinuation c, Interpreter.CallFrame current)
{
this.capturedFrame = (Interpreter.CallFrame)c.GetImplementation();
if (this.capturedFrame == null || current == null)
{
// Continuation and current execution does not share
// any frames if there is nothing to capture or
// if there is no currently executed frames
this.branchFrame = null;
}
else
{
// Search for branch frame where parent frame chains starting
// from captured and current meet.
Interpreter.CallFrame chain1 = this.capturedFrame;
Interpreter.CallFrame chain2 = current;
// First work parents of chain1 or chain2 until the same
// frame depth.
int diff = chain1.frameIndex - chain2.frameIndex;
if (diff != 0)
{
if (diff < 0)
{
// swap to make sure that
// chain1.frameIndex > chain2.frameIndex and diff > 0
chain1 = current;
chain2 = this.capturedFrame;
diff = -diff;
}
do
{
chain1 = chain1.parentFrame;
}
while (--diff != 0);
if (chain1.frameIndex != chain2.frameIndex)
{
Kit.CodeBug();
}
}
// Now walk parents in parallel until a shared frame is found
// or until the root is reached.
while (chain1 != chain2 && chain1 != null)
{
chain1 = chain1.parentFrame;
chain2 = chain2.parentFrame;
}
this.branchFrame = chain1;
if (this.branchFrame != null && !this.branchFrame.frozen)
{
Kit.CodeBug();
}
}
}
/// <summary>Construct a ContinuationPending exception.</summary>
/// <remarks>
/// Construct a ContinuationPending exception. Internal call only;
/// users of the API should get continuations created on their behalf by
/// calling
/// <see cref="Context.ExecuteScriptWithContinuations(Script, Scriptable)">Context.ExecuteScriptWithContinuations(Script, Scriptable)</see>
/// and
/// <see cref="Context.CallFunctionWithContinuations(Callable, Scriptable, object[])">Context.CallFunctionWithContinuations(Callable, Scriptable, object[])</see>
/// </remarks>
/// <param name="continuationState">Internal Continuation object</param>
internal ContinuationPending(NativeContinuation continuationState)
{
this.continuationState = continuationState;
}
public static object RestartContinuation(NativeContinuation c, Context cx, Scriptable scope, object[] args)
{
if (!ScriptRuntime.HasTopCall(cx))
{
return ScriptRuntime.DoTopCall(c, cx, scope, null, args);
}
object arg;
if (args.Length == 0)
{
arg = Undefined.instance;
}
else
{
arg = args[0];
}
Interpreter.CallFrame capturedFrame = (Interpreter.CallFrame)c.GetImplementation();
if (capturedFrame == null)
{
// No frames to restart
return arg;
}
Interpreter.ContinuationJump cjump = new Interpreter.ContinuationJump(c, null);
cjump.result = arg;
return InterpretLoop(cx, null, cjump);
}
public static void Init(Context cx, Scriptable scope, bool @sealed)
{
NativeContinuation obj = new NativeContinuation();
obj.ExportAsJSClass(MAX_PROTOTYPE_ID, scope, @sealed);
}
