Implemented OOWeakSet - like NSMutableSet, but uses weakrefs and cleans them up as needed.

Use OOWeakSet for _shipsOnHold in StationEntity. This implementation is pretty naive. I have a "better" version, only it consistently crashes a lot. Also, integrated unit tests (when building with Xcode 4). Tests are run at the end of TestRelease and Deployment builds, and can be run manually with Product -> Test. git-svn-id: http://svn.berlios.de/svnroot/repos/oolite-linux/trunk@5109 127b21dd-08f5-0310-b4b7-95ae10353056
2012-07-19 17:42:24 +00:00 · 2012-07-19 17:42:24 +00:00 · 5cafda59d9
commit 5cafda59d9
parent 3e6098fa3c
8 changed files with 483 additions and 55 deletions
--- a/Oolite.xcodeproj/project.pbxproj
+++ b/Oolite.xcodeproj/project.pbxproj
@ -667,6 +667,8 @@
 		1AED2D0C0C04586C004A1118 /* OOGraphicsResetManager.h in Headers */ = {isa = PBXBuildFile; fileRef = 1AED2D0A0C04586C004A1118 /* OOGraphicsResetManager.h */; };
 		1AED2D0D0C04586C004A1118 /* OOGraphicsResetManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 1AED2D0B0C04586C004A1118 /* OOGraphicsResetManager.m */; };
 		1AEF57D312E51DDB00546444 /* OOJSEngineNativeWrappers.h in Headers */ = {isa = PBXBuildFile; fileRef = 1AEF57D212E51DDB00546444 /* OOJSEngineNativeWrappers.h */; };
+		1AF4AF4A15B858AA009243BE /* OOWeakSet.h in Headers */ = {isa = PBXBuildFile; fileRef = 1AF4AF4815B858AA009243BE /* OOWeakSet.h */; };
+		1AF4AF4B15B858AA009243BE /* OOWeakSet.m in Sources */ = {isa = PBXBuildFile; fileRef = 1AF4AF4915B858AA009243BE /* OOWeakSet.m */; };
 		2512833E09BA27C100F43D55 /* Octree.m in Sources */ = {isa = PBXBuildFile; fileRef = 2512833C09BA27C100F43D55 /* Octree.m */; settings = {COMPILER_FLAGS = $OO_MATHS_OPTS; }; };
 		2512833F09BA27C100F43D55 /* Octree.h in Headers */ = {isa = PBXBuildFile; fileRef = 2512833D09BA27C100F43D55 /* Octree.h */; };
 		2512834209BA27EC00F43D55 /* Geometry.h in Headers */ = {isa = PBXBuildFile; fileRef = 2512834009BA27EC00F43D55 /* Geometry.h */; };
@ -800,6 +802,13 @@
 			remoteGlobalIDString = 8D5B49B6048680CD000E48DA;
 			remoteInfo = DebugOXP;
 		};
+		1AB2D62315B86EA500177AAF /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = 1AB2D61C15B86EA400177AAF /* OoliteUnitTests.xcodeproj */;
+			proxyType = 2;
+			remoteGlobalIDString = 1A0CD53615AF0BCE00970505;
+			remoteInfo = OoliteUnitTests;
+		};
 		1AB7760112CA2E53001478BB /* PBXContainerItemProxy */ = {
 			isa = PBXContainerItemProxy;
 			containerPortal = 1AB775FC12CA2E53001478BB /* libjs.xcodeproj */;
@ -1854,6 +1863,7 @@
 		1AB2AAF80C4CE0CC0008CF4E /* OOOXPVerifier.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOOXPVerifier.h; sourceTree = "<group>"; };
 		1AB2AAF90C4CE0CC0008CF4E /* OOOXPVerifier.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OOOXPVerifier.m; sourceTree = "<group>"; };
 		1AB2AB120C4CE4070008CF4E /* verifyOXP.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist; name = verifyOXP.plist; path = ../../../Resources/Config/verifyOXP.plist; sourceTree = "<group>"; };
+		1AB2D61C15B86EA400177AAF /* OoliteUnitTests.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = OoliteUnitTests.xcodeproj; path = tests/OCUnitTests/OoliteUnitTests.xcodeproj; sourceTree = "<group>"; };
 		1AB4AEB60D688AD9003076D6 /* OOLogHeader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOLogHeader.h; sourceTree = "<group>"; };
 		1AB4AEB70D688AD9003076D6 /* OOLogHeader.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OOLogHeader.m; sourceTree = "<group>"; };
 		1AB5E1ED12BD628500C334DD /* OOJoystickManager.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOJoystickManager.h; sourceTree = "<group>"; };
@ -1946,6 +1956,8 @@
 		1AED2D0A0C04586C004A1118 /* OOGraphicsResetManager.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOGraphicsResetManager.h; sourceTree = "<group>"; };
 		1AED2D0B0C04586C004A1118 /* OOGraphicsResetManager.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OOGraphicsResetManager.m; sourceTree = "<group>"; };
 		1AEF57D212E51DDB00546444 /* OOJSEngineNativeWrappers.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOJSEngineNativeWrappers.h; sourceTree = "<group>"; };
+		1AF4AF4815B858AA009243BE /* OOWeakSet.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OOWeakSet.h; sourceTree = "<group>"; };
+		1AF4AF4915B858AA009243BE /* OOWeakSet.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OOWeakSet.m; sourceTree = "<group>"; };
 		1AF8E33A0CC169F500CA6001 /* contributors.txt */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = contributors.txt; sourceTree = "<group>"; };
 		2512833C09BA27C100F43D55 /* Octree.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = Octree.m; sourceTree = "<group>"; };
 		2512833D09BA27C100F43D55 /* Octree.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = Octree.h; sourceTree = "<group>"; };
@ -2909,6 +2921,8 @@
 				1AEB4919119D5AAA007BD514 /* OORegExpMatcher.m */,
 				1A062C8711B28D8A00727C1D /* NSObjectOOExtensions.h */,
 				1A062C8811B28D8A00727C1D /* NSObjectOOExtensions.m */,
+				1AF4AF4815B858AA009243BE /* OOWeakSet.h */,
+				1AF4AF4915B858AA009243BE /* OOWeakSet.m */,
 			);
 			name = Utilities;
 			sourceTree = "<group>";
@ -3135,6 +3149,14 @@
 			path = OXPVerifier;
 			sourceTree = "<group>";
 		};
+		1AB2D61D15B86EA400177AAF /* Products */ = {
+			isa = PBXGroup;
+			children = (
+				1AB2D62415B86EA500177AAF /* OoliteUnitTests.octest */,
+			);
+			name = Products;
+			sourceTree = "<group>";
+		};
 		1AB775FD12CA2E53001478BB /* Products */ = {
 			isa = PBXGroup;
 			children = (
@ -3219,6 +3241,14 @@
 			name = Products;
 			sourceTree = "<group>";
 		};
+		1AF4AF4C15B8616F009243BE /* Unit tests */ = {
+			isa = PBXGroup;
+			children = (
+				1AB2D61C15B86EA400177AAF /* OoliteUnitTests.xcodeproj */,
+			);
+			name = "Unit tests";
+			sourceTree = "<group>";
+		};
 		29B97314FDCFA39411CA2CEA /* Oolite_GUSTO */ = {
 			isa = PBXGroup;
 			children = (
@ -3230,6 +3260,7 @@
 				1A5BF2710916D45B00BF238F /* External bundles */,
 				29B97323FDCFA39411CA2CEA /* Frameworks */,
 				19C28FACFE9D520D11CA2CBB /* Products */,
+				1AF4AF4C15B8616F009243BE /* Unit tests */,
 				1AEA229D12CBD18600EC0F43 /* CoreServices.framework */,
 				1A033F90132687DC006F9DB7 /* Quartz.framework */,
 			);
@ -3479,6 +3510,7 @@
 				1A6F665314DF323900695C11 /* OODefaultShaderSynthesizer.h in Headers */,
 				1ABA415E15ACBB6700F7E841 /* DockEntity.h in Headers */,
 				1ABA416215ADAB8D00F7E841 /* OOJSDock.h in Headers */,
+				1AF4AF4A15B858AA009243BE /* OOWeakSet.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@ -3569,6 +3601,10 @@
 					ProductGroup = 1A3E018F11C574AC000FF226 /* Products */;
 					ProjectRef = 1A3E018E11C574AC000FF226 /* Oolite-importer.xcodeproj */;
 				},
+				{
+					ProductGroup = 1AB2D61D15B86EA400177AAF /* Products */;
+					ProjectRef = 1AB2D61C15B86EA400177AAF /* OoliteUnitTests.xcodeproj */;
+				},
 				{
 					ProductGroup = 1AE3455212CB77AC00FD8C62 /* Products */;
 					ProjectRef = 1AE3455112CB77AC00FD8C62 /* Vorbis.xcodeproj */;
@ -3625,6 +3661,13 @@
 			remoteRef = 1A8FAA9D12F0E44D008FF5A2 /* PBXContainerItemProxy */;
 			sourceTree = BUILT_PRODUCTS_DIR;
 		};
+		1AB2D62415B86EA500177AAF /* OoliteUnitTests.octest */ = {
+			isa = PBXReferenceProxy;
+			fileType = wrapper.cfbundle;
+			path = OoliteUnitTests.octest;
+			remoteRef = 1AB2D62315B86EA500177AAF /* PBXContainerItemProxy */;
+			sourceTree = BUILT_PRODUCTS_DIR;
+		};
 		1AB7760212CA2E53001478BB /* libjs_for_oolite.a */ = {
 			isa = PBXReferenceProxy;
 			fileType = archive.ar;
@ -3933,6 +3976,7 @@
 				1A6F665414DF323900695C11 /* OODefaultShaderSynthesizer.m in Sources */,
 				1ABA415F15ACBB6700F7E841 /* DockEntity.m in Sources */,
 				1ABA416315ADAB8D00F7E841 /* OOJSDock.m in Sources */,
+				1AF4AF4B15B858AA009243BE /* OOWeakSet.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@ -4071,6 +4115,7 @@
 				);
 				PRODUCT_NAME = Oolite;
 				SECTORDER_FLAGS = "";
+				TEST_AFTER_BUILD = YES;
 				USER_HEADER_SEARCH_PATHS = "\"$(DEPS_INCLUDE_PATH)/ogg\" \"$(DEPS_INCLUDE_PATH)/js\" \"$(DEPS_INCLUDE_PATH)/vorbis\" \"$(DEPS_INCLUDE_PATH)/png\" \"$(SRCROOT)/src/Core/\" \"$(SRCROOT)/src/Core/Tables/\" \"$(SRCROOT)/src/Core/Entites/\" \"$(SRCROOT)/src/Core/Materials/\" \"$(SRCROOT)/src/BSDCompat/\"";
 				WARNING_CFLAGS = (
 					"-Wall",
@ -4137,6 +4182,7 @@
 				);
 				PRODUCT_NAME = Oolite;
 				SECTORDER_FLAGS = "";
+				TEST_AFTER_BUILD = YES;
 				USER_HEADER_SEARCH_PATHS = "\"$(DEPS_INCLUDE_PATH)/ogg\" \"$(DEPS_INCLUDE_PATH)/js\" \"$(DEPS_INCLUDE_PATH)/vorbis\" \"$(DEPS_INCLUDE_PATH)/png\" \"$(SRCROOT)/src/Core/\" \"$(SRCROOT)/src/Core/Tables/\" \"$(SRCROOT)/src/Core/Entites/\" \"$(SRCROOT)/src/Core/Materials/\" \"$(SRCROOT)/src/BSDCompat/\"";
 				WARNING_CFLAGS = (
 					"-Wall",
--- a/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
+++ b/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
@ -42,6 +42,16 @@
      shouldUseLaunchSchemeArgsEnv = "YES"
      buildConfiguration = "Debug">
      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1A0CD53515AF0BCE00970505"
+               BuildableName = "OoliteUnitTests.octest"
+               BlueprintName = "OoliteUnitTests"
+               ReferencedContainer = "container:tests/OCUnitTests/OoliteUnitTests.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
      </Testables>
      <MacroExpansion>
         <BuildableReference
--- a/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
+++ b/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
@ -34,6 +34,20 @@
               ReferencedContainer = "container:Oolite.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1A0CD53515AF0BCE00970505"
+               BuildableName = "OoliteUnitTests.octest"
+               BlueprintName = "OoliteUnitTests"
+               ReferencedContainer = "container:tests/OCUnitTests/OoliteUnitTests.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
      </BuildActionEntries>
   </BuildAction>
   <TestAction
@ -42,6 +56,16 @@
      shouldUseLaunchSchemeArgsEnv = "YES"
      buildConfiguration = "Deployment">
      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1A0CD53515AF0BCE00970505"
+               BuildableName = "OoliteUnitTests.octest"
+               BlueprintName = "OoliteUnitTests"
+               ReferencedContainer = "container:tests/OCUnitTests/OoliteUnitTests.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
      </Testables>
      <MacroExpansion>
         <BuildableReference
@ -55,7 +79,7 @@
   </TestAction>
   <LaunchAction
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.GDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      buildConfiguration = "Deployment"
--- a/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
+++ b/Oolite.xcodeproj/xcshareddata/xcschemes/Oolite
@ -21,7 +21,7 @@
            </BuildableReference>
         </BuildActionEntry>
         <BuildActionEntry
-            buildForTesting = "NO"
+            buildForTesting = "YES"
            buildForRunning = "YES"
            buildForProfiling = "YES"
            buildForArchiving = "YES"
@ -34,6 +34,20 @@
               ReferencedContainer = "container:Oolite.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1A0CD53515AF0BCE00970505"
+               BuildableName = "OoliteUnitTests.octest"
+               BlueprintName = "OoliteUnitTests"
+               ReferencedContainer = "container:tests/OCUnitTests/OoliteUnitTests.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
      </BuildActionEntries>
   </BuildAction>
   <TestAction
@ -42,6 +56,16 @@
      shouldUseLaunchSchemeArgsEnv = "YES"
      buildConfiguration = "TestRelease">
      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1A0CD53515AF0BCE00970505"
+               BuildableName = "OoliteUnitTests.octest"
+               BlueprintName = "OoliteUnitTests"
+               ReferencedContainer = "container:tests/OCUnitTests/OoliteUnitTests.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
      </Testables>
      <MacroExpansion>
         <BuildableReference
--- a/src/Core/Entities/StationEntity.h
+++ b/src/Core/Entities/StationEntity.h
@ -26,7 +26,9 @@ MA 02110-1301, USA.

 #import "ShipEntity.h"
 #import "Universe.h"
-#import "legacy_random.h"
+
+@class OOWeakSet;
+

 typedef enum
 {
@ -45,10 +47,11 @@ typedef enum

 #define DOCKING_CLEARANCE_WINDOW		126.0

+
@interface StationEntity: ShipEntity
 {
@private
-	NSMutableSet			*_shipsOnHold;
+	OOWeakSet				*_shipsOnHold;
 	DockEntity				*player_reserved_dock;
 	double					last_launch_time;
 	double					approach_spacing;
--- a/src/Core/Entities/StationEntity.m
+++ b/src/Core/Entities/StationEntity.m
@ -44,6 +44,7 @@ MA 02110-1301, USA.
 #import "OOJSScript.h"
 #import "OODebugGLDrawing.h"
 #import "OODebugFlags.h"
+#import "OOWeakSet.h"


@interface StationEntity (OOPrivate)
@ -57,8 +58,6 @@ MA 02110-1301, USA.

 - (NSDictionary *) holdPositionInstructionForShip:(ShipEntity *)ship;

- (void) compactShipsOnHold;
-
@end


@ -244,28 +243,11 @@ MA 02110-1301, USA.
 		// if all docks have no ships on approach
 		[shipAI message:@"DOCKING_COMPLETE"];
 	}
-	
-	[self compactShipsOnHold];
-}
-
-
- (void) compactShipsOnHold
-{
-	NSArray *ships = [_shipsOnHold allObjects];
-	OOUInteger i, count = [ships count];
-	for (i = 0; i < count; i++)
-	{
-		OOWeakReference *ref = [ships objectAtIndex:i];
-		if ([ref weakRefUnderlyingObject] == nil)
-		{
-			[_shipsOnHold removeObject:ref];
-		}
-	}
 }


 // only used by player - everything else ends up in a Dock's launch queue
- (void) launchShip:(ShipEntity*)ship
+- (void) launchShip:(ShipEntity *)ship
 {
 	NSEnumerator	*subEnum = nil;
 	DockEntity* sub = nil;
@ -303,17 +285,13 @@ MA 02110-1301, USA.
 - (void) abortAllDockings
 {
 	NSEnumerator	*subEnum = nil;
-	DockEntity* sub = nil;
+	DockEntity		*sub = nil;
 	for (subEnum = [self dockSubEntityEnumerator]; (sub = [subEnum nextObject]); )
 	{
 		[sub abortAllDockings];
 	}
 	
-	OOWeakReference *ref = nil;
-	foreach (ref, _shipsOnHold)
-	{
-		[[ref weakRefUnderlyingObject] sendAIMessage:@"DOCKING_ABORTED"];
-	}
+	[_shipsOnHold makeObjectsPerformSelector:@selector(sendAIMessage:) withObject:@"DOCKING_ABORTED"];
 	[_shipsOnHold removeAllObjects];
 	
 	[shipAI message:@"DOCKING_COMPLETE"];
@ -323,14 +301,11 @@ MA 02110-1301, USA.

 - (void) autoDockShipsOnHold
 {
-	OOWeakReference *ref = nil;
-	foreach (ref, _shipsOnHold)
+	NSEnumerator	*onHoldEnum = [_shipsOnHold objectEnumerator];
+	ShipEntity		*ship = nil;
+	while ((ship = [onHoldEnum nextObject]))
 	{
-		ShipEntity *ship = [ref weakRefUnderlyingObject];
-		if (ship != nil)
-		{
-			[self pullInShipIfPermitted:ship];
-		}
+		[self pullInShipIfPermitted:ship];
 	}
 	
 	[_shipsOnHold removeAllObjects];
@ -488,9 +463,7 @@ NSDictionary *OOMakeDockingInstructions(StationEntity *station, Vector coords, f
 	}
 	
 	// we made it through holding!
-	OOWeakReference *weakShip = [ship weakRetain];
-	[_shipsOnHold removeObject:weakShip];
-	[weakShip release];
+	[_shipsOnHold removeObject:ship];
 	
 	[shipAI reactToMessage:@"DOCKING_REQUESTED" context:@"requestDockingCoordinates"];	// react to the request	
 	
@ -498,15 +471,13 @@ NSDictionary *OOMakeDockingInstructions(StationEntity *station, Vector coords, f
 }


- (NSDictionary *) holdPositionInstructionForShip:(ShipEntity *)ship
+- (NSDictionary *)holdPositionInstructionForShip:(ShipEntity *)ship
 {
-	OOWeakReference *weakShip = [ship weakRetain];
-	if (![_shipsOnHold containsObject:weakShip])
+	if (![_shipsOnHold containsObject:ship])
 	{
 		[self sendExpandedMessage:@"[station-acknowledges-hold-position]" toShip:ship];
-		[_shipsOnHold addObject:weakShip];
+		[_shipsOnHold addObject:ship];
 	}
-	[weakShip release];
 	
 	return OOMakeDockingInstructions(self, [ship position], 0, 100, @"HOLD_POSITION", nil, NO);
 }
@ -516,9 +487,7 @@ NSDictionary *OOMakeDockingInstructions(StationEntity *station, Vector coords, f
 {
 	[ship sendAIMessage:@"DOCKING_ABORTED"];
 	
-	OOWeakReference *weakShip = [ship weakRetain];
-	[_shipsOnHold removeObject:weakShip];
-	[weakShip release];
+	[_shipsOnHold removeObject:ship];
 	
 	NSEnumerator	*subEnum = nil;
 	DockEntity		*sub = nil;
@ -546,7 +515,7 @@ NSDictionary *OOMakeDockingInstructions(StationEntity *station, Vector coords, f
 	if (self != nil)
 	{
 		isStation = YES;
-		_shipsOnHold = [[NSMutableSet alloc] init];
+		_shipsOnHold = [[OOWeakSet alloc] init];
 	}
 	
 	return self;
@ -2296,17 +2265,17 @@ NSDictionary *OOMakeDockingInstructions(StationEntity *station, Vector coords, f
 		} */
 	
 	// Ships on hold list, only used with moving stations (= carriers)
-	[self compactShipsOnHold];
 	if([_shipsOnHold count] > 0)
 	{
 		OOLog(@"dumpState.stationEntity", @"%i Ships on hold (unsorted):", [_shipsOnHold count]);
-		OOWeakReference *ref = nil;
+		
 		OOLogIndent();
-		unsigned i = 1;
-		foreach (ref, _shipsOnHold)
+		NSEnumerator	*onHoldEnum = [_shipsOnHold objectEnumerator];
+		ShipEntity		*ship = nil;
+		unsigned		i = 1;
+		while ((ship = [onHoldEnum nextObject]))
 		{
-			ShipEntity *ship = [ref weakRefUnderlyingObject];
-			OOLog(@"dumpState.stationEntity", @"Nr %i: %@ at distance %g with role: %@", i++, [ship displayName], distance(position, [ship position]), [ship primaryRole]);
+			OOLog(@"dumpState.stationEntity", @"Nr %i: %@ at distance %g with role: %@", i++, [ship displayName], distance([self position], [ship position]), [ship primaryRole]);
 		}
 		OOLogOutdent();
 	}
--- a/src/Core/OOWeakSet.h
+++ b/src/Core/OOWeakSet.h
@ -0,0 +1,54 @@
+/*
+
+OOWeakSet.h
+
+A mutable set of weak references to objects conforming to OOWeakReferenceSupport.
+
+Semantics:
+ * When an object in the set is deallocated, the object is removed from the
+   set and the set's count drops. There is no notification for this. As such,
+   there is no such thing as an immutable weak set.
+ * Objects are uniqued by pointer equality, not isEquals:.
+ * OOWeakSet is not thread-safe. It not only requires that all operations on
+   it happen on one thread, but also that objects it's watching are (finally)
+   released on that thread.
+
+
+LIMITATION: fast enumeration and Oolite's foreach() macro are not supported.
+
+
+Written by Jens Ayton in 2012 for Oolite.
+This code is hereby placed in the public domain.
+
+*/
+
+#import "OOWeakReference.h"
+
+
+@interface OOWeakSet: NSObject <NSCopying, NSMutableCopying>
+{
+@private
+	NSMutableSet			*_objects;
+}
+
+- (id) init;
+- (id) initWithCapacity:(NSUInteger)capacity;				// As with Foundation collections, capacity is only a hint.
+
+ (id) set;
+ (id) setWithCapacity:(NSUInteger)capacity;
+
+- (NSUInteger) count;
+- (BOOL) containsObject:(id<OOWeakReferenceSupport>)object;
+- (NSEnumerator *) objectEnumerator;
+
+- (void) addObject:(id<OOWeakReferenceSupport>)object;		// Unlike NSSet, adding nil fails silently.
+- (void) removeObject:(id<OOWeakReferenceSupport>)object;	// Like NSSet, does not complain if object is not already a member.
+
+- (void) addObjectsByEnumerating:(NSEnumerator *)enumerator;
+
+- (void) makeObjectsPerformSelector:(SEL)selector;
+- (void) makeObjectsPerformSelector:(SEL)selector withObject:(id)argument;
+
+- (void) removeAllObjects;
+
+@end
--- a/src/Core/OOWeakSet.m
+++ b/src/Core/OOWeakSet.m
@ -0,0 +1,298 @@
+/*
+
+OOWeakSet.h
+
+Written by Jens Ayton in 2012 for Oolite.
+This code is hereby placed in the public domain.
+
+*/
+
+#import "OOWeakSet.h"
+#import "OOCocoa.h"
+
+
+@interface OOWeakRefUnpackingEnumerator: NSEnumerator
+{
+@private
+	NSEnumerator			*_enumerator;
+}
+
+- (id) initWithEnumerator:(NSEnumerator *)enumerator;
+
+ (id) enumeratorWithCollection:(id)collection;	// Collection must implement -objectEnumerator
+
+@end
+
+
+@interface OOWeakSet (OOPrivate)
+
+- (void) compact;	// Remove any zeroed entries.
+
+@end
+
+
+@implementation OOWeakSet
+
+- (id) init
+{
+	return [self initWithCapacity:0];
+}
+
+
+- (id) initWithCapacity:(OOUInteger)capacity
+{
+	if ((self = [super init]))
+	{
+		_objects = [[NSMutableSet alloc] initWithCapacity:capacity];
+		if (_objects == NULL)
+		{
+			[self release];
+			return nil;
+		}
+	}
+	return self;
+}
+
+
+ (id) set
+{
+	return [[[self alloc] init] autorelease];
+}
+
+
+ (id) setWithCapacity:(OOUInteger)capacity
+{
+	return [[[self alloc] initWithCapacity:capacity] autorelease];
+}
+
+
+- (void) dealloc
+{
+	DESTROY(_objects);
+	
+	[super dealloc];
+}
+
+
+- (NSString *) description
+{
+	NSMutableString *result = [NSMutableString stringWithFormat:@"<%@ %p>{", [self class], self];
+	NSEnumerator *selfEnum = [self objectEnumerator];
+	id object = nil;
+	BOOL first = YES;
+	while ((object = [selfEnum nextObject]))
+	{
+		if (!first)  [result appendString:@", "];
+		else  first = NO;
+		
+		NSString *desc = nil;
+		if ([object respondsToSelector:@selector(shortDescription)])  desc = [object shortDescription];
+		else  desc = [object description];
+		
+		[result appendString:desc];
+	}
+	
+	[result appendString:@"}"];
+	return result;
+}
+
+
+// MARK: Protocol conformance
+
+- (id) copyWithZone:(NSZone *)zone
+{
+	[self compact];
+	OOWeakSet *result = [[OOWeakSet allocWithZone:zone] init];
+	[result addObjectsByEnumerating:[self objectEnumerator]];
+	return result;
+}
+
+
+- (id) mutableCopyWithZone:(NSZone *)zone
+{
+	return [self copyWithZone:zone];
+}
+
+
+- (BOOL) isEqual:(id)other
+{
+	if (![other isKindOfClass:[OOWeakSet class]])  return NO;
+	if ([self count] != [other count])  return NO;
+	
+	BOOL result = YES;
+	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+	NSEnumerator *selfEnum = [self objectEnumerator];
+	id object = nil;
+	while ((object = [selfEnum nextObject]))
+	{
+		if (![other containsObject:object])
+		{
+			result = NO;
+			break;
+		}
+	}
+	DESTROY(pool);
+	
+	return result;
+}
+
+
+// MARK: Meat and potatoes
+
+- (OOUInteger) count
+{
+	[self compact];
+	return [_objects count];
+}
+
+
+- (BOOL) containsObject:(id<OOWeakReferenceSupport>)object
+{
+	[self compact];
+	OOWeakReference *weakObj = [object weakRetain];
+	BOOL result = [_objects containsObject:weakObj];
+	[weakObj release];
+	return result;
+}
+
+
+- (NSEnumerator *) objectEnumerator
+{
+	return [OOWeakRefUnpackingEnumerator enumeratorWithCollection:_objects];
+}
+
+
+- (void) addObject:(id<OOWeakReferenceSupport>)object
+{
+	if (object == nil)  return;
+	NSAssert([object conformsToProtocol:@protocol(OOWeakReferenceSupport)], @"Attempt to add object to OOWeakSet which does not conform to OOWeakReferenceSupport.");
+	
+	OOWeakReference *weakObj = [object weakRetain];
+	[_objects addObject:weakObj];
+	[weakObj release];
+}
+
+
+- (void) removeObject:(id<OOWeakReferenceSupport>)object
+{
+	OOWeakReference *weakObj = [object weakRetain];
+	[_objects removeObject:weakObj];
+	[weakObj release];
+}
+
+
+- (void) addObjectsByEnumerating:(NSEnumerator *)enumerator
+{
+	id object = nil;
+	[self compact];
+	while ((object = [enumerator nextObject]))
+	{
+		[self addObject:object];
+	}
+}
+
+
+- (void) makeObjectsPerformSelector:(SEL)selector
+{
+	OOWeakReference *weakRef = nil;
+	foreach (weakRef, _objects)
+	{
+		[[weakRef weakRefUnderlyingObject] performSelector:selector];
+	}
+}
+
+
+- (void) makeObjectsPerformSelector:(SEL)selector withObject:(id)argument
+{
+	OOWeakReference *weakRef = nil;
+	foreach (weakRef, _objects)
+	{
+		[[weakRef weakRefUnderlyingObject] performSelector:selector withObject:argument];
+	}
+}
+
+
+- (void) removeAllObjects
+{
+	[_objects removeAllObjects];
+}
+
+
+- (void) compact
+{
+	OOWeakReference *weakRef = nil;
+	BOOL compactRequired = NO;
+	foreach (weakRef, _objects)
+	{
+		if ([weakRef weakRefUnderlyingObject] == nil)
+		{
+			compactRequired = YES;
+			break;
+		}
+	}
+	
+	if (compactRequired)
+	{
+		NSMutableSet *newObjects = [[NSMutableSet alloc] initWithCapacity:[_objects count]];
+		foreach (weakRef, _objects)
+		{
+			if ([weakRef weakRefUnderlyingObject] != nil)
+			{
+				[newObjects addObject:weakRef];
+			}
+		}
+		
+		[_objects release];
+		_objects = newObjects;
+	}
+}
+
+@end
+
+
+@implementation OOWeakRefUnpackingEnumerator
+
+- (id) initWithEnumerator:(NSEnumerator *)enumerator
+{
+	if (enumerator == nil)
+	{
+		[self release];
+		return nil;
+	}
+	
+	if ((self = [super init]))
+	{
+		_enumerator = [enumerator retain];
+	}
+	
+	return self;
+}
+
+
+ (id) enumeratorWithCollection:(id)collection
+{
+	return [[[self alloc] initWithEnumerator:[collection objectEnumerator]] autorelease];
+}
+
+
+- (void) dealloc
+{
+	[_enumerator release];
+	
+	[super dealloc];
+}
+
+
+- (id) nextObject
+{
+	id next = nil;
+	while ((next = [_enumerator nextObject]))
+	{
+		next = [next weakRefUnderlyingObject];
+		if (next != nil)  return next;
+	}
+	
+	return nil;
+}
+
+@end