From 1f80f2eec3fcca13f5d0f4e146bde2058672a0ab Mon Sep 17 00:00:00 2001
From: Rene Gollent <anevilyak@gmail.com>
Date: Thu, 19 Jul 2012 20:21:06 -0400
Subject: [PATCH] Fix #8749.

- When a job needs to go dependent on another job, we no longer use recursion
  to manage the execution stack. Instead the job is simply marked as waiting
  and we execute other jobs with no dependencies in the meantime. When a job
  completes, all dependents are moved back onto the unscheduled list and
  executed as needed.

- Adjustments to ResolveValueNodeJob to handle the now asynchronous nature
  of waiting.
---
 src/apps/debugger/Jobs.cpp   |  6 +++++
 src/apps/debugger/Worker.cpp | 45 +++++++++++++++++-------------------
 src/apps/debugger/Worker.h   |  2 +-
 3 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/src/apps/debugger/Jobs.cpp b/src/apps/debugger/Jobs.cpp
index 0e812cc114..bfd2fe11dc 100644
--- a/src/apps/debugger/Jobs.cpp
+++ b/src/apps/debugger/Jobs.cpp
@@ -1,4 +1,5 @@
 /*
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
@@ -523,6 +524,9 @@ ResolveValueNodeValueJob::_ResolveNodeValue()
 				fValueNode, fValueNode->Name().String(), parentNode);
 			return error;
 		}
+
+		if (State() == JOB_STATE_WAITING)
+			return B_OK;
 	}
 
 	// resolve the node child location, if necessary
@@ -629,6 +633,8 @@ ResolveValueNodeValueJob::_ResolveParentNodeValue(ValueNode* parentNode)
 			// "Not found" can happen due to a race condition between
 			// unlocking the worker and starting to wait.
 			break;
+		case JOB_DEPENDENCY_ACTIVE:
+			return B_OK;
 		case JOB_DEPENDENCY_FAILED:
 		case JOB_DEPENDENCY_ABORTED:
 		default:
diff --git a/src/apps/debugger/Worker.cpp b/src/apps/debugger/Worker.cpp
index dc1f06af09..409ff2b5b9 100644
--- a/src/apps/debugger/Worker.cpp
+++ b/src/apps/debugger/Worker.cpp
@@ -1,4 +1,5 @@
 /*
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Copyright 2009, Ingo Weinhold, ingo_weinhold@gmx.de.
  * Distributed under the terms of the MIT License.
  */
@@ -138,6 +139,15 @@ void
 Job::SetWaitStatus(job_wait_status status)
 {
 	fWaitStatus = status;
+	switch (fWaitStatus) {
+	case JOB_DEPENDENCY_ACTIVE:
+		fState = JOB_STATE_WAITING;
+		break;
+	default:
+		fState = JOB_STATE_ACTIVE;
+		break;
+
+	}
 }
 
 
@@ -346,18 +356,6 @@ Worker::WaitForJob(Job* waitingJob, const JobKey& key)
 	waitingJob->SetDependency(job);
 	job->DependentJobs().Add(waitingJob);
 
-	// TODO: Continuations would be nice. For the time being we have to use
-	// recursion. Disadvantages are that we'll use more stack and that aborting
-	// a job waiting for a dependency won't abort the job before the dependency
-	// is done.
-	locker.Unlock();
-	_ProcessJobs(waitingJob);
-	locker.Lock();
-
-	// ignore the actual wait status when the game is over anyway
-	if (fTerminating || waitingJob->State() == JOB_STATE_ABORTED)
-		return JOB_DEPENDENCY_ABORTED;
-
 	return waitingJob->WaitStatus();
 }
 
@@ -372,7 +370,7 @@ Worker::_WorkerLoopEntry(void* data)
 status_t
 Worker::_WorkerLoop()
 {
-	_ProcessJobs(NULL);
+	_ProcessJobs();
 
 	// clean up aborted jobs
 	AutoLocker<Worker> locker(this);
@@ -384,7 +382,7 @@ Worker::_WorkerLoop()
 
 
 void
-Worker::_ProcessJobs(Job* waitingJob)
+Worker::_ProcessJobs()
 {
 	while (true) {
 		AutoLocker<Worker> locker(this);
@@ -395,8 +393,10 @@ Worker::_ProcessJobs(Job* waitingJob)
 
 			status_t error = acquire_sem(fWorkToDoSem);
 			if (error != B_OK) {
-				if (error == B_INTERRUPTED)
+				if (error == B_INTERRUPTED) {
+					locker.Lock();
 					continue;
+				}
 				break;
 			}
 
@@ -404,13 +404,9 @@ Worker::_ProcessJobs(Job* waitingJob)
 		}
 
 		// clean up aborted jobs
-		while (Job* job = fAbortedJobs.RemoveHead()) {
+		while (Job* job = fAbortedJobs.RemoveHead())
 			_FinishJob(job);
 
-			if (waitingJob != NULL && waitingJob->State() != JOB_STATE_WAITING)
-				break;
-		}
-
 		// process the next job
 		if (Job* job = fUnscheduledJobs.RemoveHead()) {
 			job->SetState(JOB_STATE_ACTIVE);
@@ -422,12 +418,10 @@ Worker::_ProcessJobs(Job* waitingJob)
 			if (job->State() == JOB_STATE_ACTIVE) {
 				job->SetState(
 					error == B_OK ? JOB_STATE_SUCCEEDED : JOB_STATE_FAILED);
-			}
+			} else if (job->State() == JOB_STATE_WAITING)
+				continue;
 
 			_FinishJob(job);
-
-			if (waitingJob != NULL && waitingJob->State() != JOB_STATE_WAITING)
-				break;
 		}
 	}
 }
@@ -492,7 +486,10 @@ Worker::_FinishJob(Job* job)
 		while (Job* dependentJob = job->DependentJobs().RemoveHead()) {
 			dependentJob->SetDependency(NULL);
 			dependentJob->SetWaitStatus(waitStatus);
+			fUnscheduledJobs.Add(dependentJob);
 		}
+
+		release_sem(fWorkToDoSem);
 	}
 
 	if (job->State() != JOB_STATE_ABORTED)
diff --git a/src/apps/debugger/Worker.h b/src/apps/debugger/Worker.h
index 241a3f4afa..7e356992a7 100644
--- a/src/apps/debugger/Worker.h
+++ b/src/apps/debugger/Worker.h
@@ -182,7 +182,7 @@ private:
 	static	status_t			_WorkerLoopEntry(void* data);
 			status_t			_WorkerLoop();
 
-			void				_ProcessJobs(Job* waitingJob);
+			void				_ProcessJobs();
 			void				_AbortJob(Job* job, bool removeFromTable);
 			void				_FinishJob(Job* job);