Bug 540004, part 3: Add a ShouldContinue() interface to IPDL actors that allows them to decide how a hang should be treated. r=bent

ipc/glue/RPCChannel.h

@@ -61,6 +61,7 @@ public:
         virtual void OnChannelClose() = 0;
         virtual void OnChannelError() = 0;
         virtual Result OnMessageReceived(const Message& aMessage) = 0;
+        virtual bool OnReplyTimeout() = 0;
         virtual Result OnMessageReceived(const Message& aMessage,
                                          Message*& aReply) = 0;
         virtual Result OnCallReceived(const Message& aMessage,

ipc/glue/SyncChannel.cpp

@@ -237,7 +237,11 @@ SyncChannel::ShouldContinueFromTimeout()
     AssertWorkerThread();
     mMutex.AssertCurrentThreadOwns();
 
-    bool cont = true;
+    bool cont;
+    {
+        MutexAutoUnlock unlock(mMutex);
+        cont = static_cast<SyncListener*>(mListener)->OnReplyTimeout();
+    }
 
     if (!cont) {
         // NB: there's a sublety here.  If parents were allowed to

ipc/glue/SyncChannel.h

@@ -67,6 +67,7 @@ public:
         virtual void OnChannelClose() = 0;
         virtual void OnChannelError() = 0;
         virtual Result OnMessageReceived(const Message& aMessage) = 0;
+        virtual bool OnReplyTimeout() = 0;
         virtual Result OnMessageReceived(const Message& aMessage,
                                          Message*& aReply) = 0;
     };
@@ -81,6 +82,11 @@ public:
     // Synchronously send |msg| (i.e., wait for |reply|)
     bool Send(Message* msg, Message* reply);
 
+    void SetReplyTimeoutMs(int32 aTimeoutMs) {
+        AssertWorkerThread();
+        mTimeoutMs = (aTimeoutMs <= 0) ? kNoTimeout : aTimeoutMs;
+    }
+
     // Override the AsyncChannel handler so we can dispatch sync messages
     NS_OVERRIDE virtual void OnMessageReceived(const Message& msg);
     NS_OVERRIDE virtual void OnChannelError();

ipc/ipdl/ipdl/cxx/ast.py

@@ -342,6 +342,7 @@ Any type, naked or pointer, can be const (const T) or ref (T&).
                     T=copy.deepcopy(self.T, memo))
 Type.BOOL = Type('bool')
 Type.INT = Type('int')
+Type.INT32 = Type('int32')
 Type.INTPTR = Type('intptr_t')
 Type.UINT32 = Type('uint32')
 Type.SIZE = Type('size_t')

ipc/ipdl/ipdl/lower.py

@@ -1344,6 +1344,10 @@ class Protocol(ipdl.ast.Protocol):
     def otherProcessMethod(self):
         return ExprVar('OtherProcess')
 
+    def shouldContinueFromTimeoutVar(self):
+        assert self.decl.type.isToplevel()
+        return ExprVar('ShouldContinueFromReplyTimeout')
+
     def nextActorIdExpr(self, side):
         assert self.decl.type.isToplevel()
         if side is 'parent':   op = '++'
@@ -2629,6 +2633,14 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
             Whitespace.NL
         ])
 
+        if ptype.isToplevel():
+            # bool ShouldContinueFromReplyTimeout(); default to |true|
+            shouldcontinue = MethodDefn(
+                MethodDecl(p.shouldContinueFromTimeoutVar().name,
+                           ret=Type.BOOL, virtual=1))
+            shouldcontinue.addstmt(StmtReturn(ExprLiteral.TRUE))
+            self.cls.addstmts([ shouldcontinue, Whitespace.NL ])
+
         self.cls.addstmts((
             [ Label.PRIVATE ]
             + self.standardTypedefs()
@@ -2698,6 +2710,18 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
                 ExprCall(ExprSelect(p.channelVar(), '.', 'Close'))))
             self.cls.addstmts([ closemeth, Whitespace.NL ])
 
+            if ptype.talksSync() or ptype.talksRpc():
+                # SetReplyTimeoutMs()
+                timeoutvar = ExprVar('aTimeoutMs')
+                settimeout = MethodDefn(MethodDecl(
+                    'SetReplyTimeoutMs',
+                    params=[ Decl(Type.INT32, timeoutvar.name) ]))
+                settimeout.addstmt(StmtExpr(
+                    ExprCall(
+                        ExprSelect(p.channelVar(), '.', 'SetReplyTimeoutMs'),
+                        args=[ timeoutvar ])))
+                self.cls.addstmts([ settimeout, Whitespace.NL ])
+
         if not ptype.isToplevel():
             if 1 == len(p.managers):
                 ## manager()
@@ -2820,6 +2844,22 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
         destroysubtreevar = ExprVar('DestroySubtree')
         deallocsubtreevar = ExprVar('DeallocSubtree')
 
+        # OnReplyTimeout()
+        if toplevel.talksSync() or toplevel.talksRpc():
+            ontimeout = MethodDefn(
+                MethodDecl('OnReplyTimeout', ret=Type.BOOL))
+
+            if ptype.isToplevel():
+                ontimeout.addstmt(StmtReturn(
+                    ExprCall(p.shouldContinueFromTimeoutVar())))
+            else:
+                ontimeout.addstmts([
+                    _runtimeAbort("`OnReplyTimeout' called on non-toplevel actor"),
+                    StmtReturn(ExprLiteral.FALSE)
+                ])
+
+            self.cls.addstmts([ ontimeout, Whitespace.NL ])
+
         # OnChannelClose()
         onclose = MethodDefn(MethodDecl('OnChannelClose'))
         if ptype.isToplevel():