Fix demand-loaded building artwork ownership

code/animtype.cpp

@@ -64,6 +64,16 @@
 #include "warhead.h"
 
 
+/// <summary>
+/// Releases shape data that this type loaded through the file layer.
+/// </summary>
+static void Free_Demand_Loaded_Shape(void const *& data)
+{
+	delete [] (char *)data;
+	data = NULL;
+}
+
+
 /***********************************************************************************************
  * AnimTypeClass::AnimTypeClass -- Constructor for animation types.                            *
  *                                                                                             *
@@ -172,8 +182,7 @@ AnimTypeClass::AnimTypeClass(char const *ininame) :
 AnimTypeClass::~AnimTypeClass(void)
 {
 	if (IsDemandLoad && ImageData) {
-		delete [] (char*) ImageData;
-		ImageData = NULL;
+		Free_Demand_Loaded_Shape(ImageData);
 	}
 
 	AbstractTypePtrTracker.Delete(this);
@@ -219,8 +228,7 @@ void AnimTypeClass::Init(TheaterType theater)
 			} else {
 				if (anim->IsTheater || anim->IsNewTheater) {
 					if (anim->ImageData != NULL) {
-						delete [] (char*) anim->ImageData;
-						anim->ImageData = NULL;
+						Free_Demand_Loaded_Shape(anim->ImageData);
 					}
 				}
 			}
@@ -358,6 +366,14 @@ AnimType AnimTypeClass::From_Name(char const * name)
 /// <returns>bool; Was the animation type's data read?</returns>
 bool AnimTypeClass::Read_INI(CCINIClass const & ini)
 {
+	if (!ini.Section_Present(IniName)) {
+		return(false);
+	}
+
+	if (IsDemandLoad && ImageData != NULL) {
+		Free_Demand_Loaded_Shape(ImageData);
+	}
+
 	if (BASECLASS::Read_INI(ini)) {
 		if (!GraphicName.empty()) {
 			if (ImageData == NULL) {
@@ -407,6 +423,9 @@ bool AnimTypeClass::Read_INI(CCINIClass const & ini)
 
 		IsDemandLoad = ini.Get_Bool(Name(), "DemandLoad", IsDemandLoad);
 		IsFreeAfterPlaying = ini.Get_Bool(Name(), "FreeAfterPlaying", IsFreeAfterPlaying);
+		if (IsDemandLoad) {
+			ImageData = NULL;
+		}
 
 		Elasticity = ini.Get_Float(Name(), "Elasticity", Elasticity);
 		MaxXYVel = ini.Get_Float(Name(), "MaxXYVel", MaxXYVel);
@@ -472,9 +491,9 @@ void AnimTypeClass::Post_Load(void)
 	BASECLASS::Post_Load();
 
 	Fetch_Voxel_Image();
-	Fetch_Normal_Image();
 
 	if (!IsDemandLoad) {
+		Fetch_Normal_Image();
 		if (IsTheater) {
 			char fullname[_MAX_FNAME+_MAX_EXT];	// Fully constructed iconset name.
 			_makepath(fullname, NULL, NULL, Name(), Theaters[Scen->Theater].Suffix);
@@ -681,7 +700,6 @@ void AnimTypeClass::Free_Image(void)
 {
 	if (IsDemandLoad && ImageData != NULL && IsFreeAfterPlaying) {
 		DebugString("Freeing loaded image for %s\n", Full_Name());
-		delete [] (char*) ImageData;
-		ImageData = NULL;
+		Free_Demand_Loaded_Shape(ImageData);
 	}
 }

code/builtype.cpp

@@ -98,6 +98,15 @@ void const * BuildingTypeClass::WrenchShapes;
 
 BSurface * CloakingSurface;
 
+/// <summary>
+/// Releases shape data that this type loaded through the file layer.
+/// </summary>
+static void Free_Demand_Loaded_Shape(void const *& data)
+{
+	delete [] (char *)data;
+	data = NULL;
+}
+
 Cell const BuildingTypeClass::OccupyLists[BSIZE_COUNT][24] = {
 	/* BSIZE_11,	*/ { Cell(0,0),REFRESH_EOL },
 	/* BSIZE_21,	*/ { Cell(0,0),Cell(1,0),REFRESH_EOL },
@@ -366,12 +375,10 @@ BuildingTypeClass::BuildingTypeClass(char const * ininame) :
 BuildingTypeClass::~BuildingTypeClass(void)
 {
 	if (IsDemandLoad && ImageData != NULL) {
-		delete (ShapeSet *)ImageData;
-		ImageData = NULL;
+		Free_Demand_Loaded_Shape(ImageData);
 	}
 	if (IsDemandLoadBuildup && BuildupData != NULL) {
-		delete (ShapeSet *)BuildupData;
-		BuildupData = NULL;
+		Free_Demand_Loaded_Shape(BuildupData);
 	}
 	Detach_This_From_All(this, true);
 	BuildingTypes.Delete(this);
@@ -603,8 +610,7 @@ void BuildingTypeClass::Init(TheaterType theater)
 				classptr->ImageData = MFCD::Retrieve(fullname);
 			} else {
 				if (classptr->ImageData != NULL) {
-					delete (ShapeSet *)classptr->ImageData;
-					classptr->ImageData = NULL;
+					Free_Demand_Loaded_Shape(classptr->ImageData);
 				}
 			}
 
@@ -617,8 +623,7 @@ void BuildingTypeClass::Init(TheaterType theater)
 				classptr->BuildupData = MFCD::Retrieve(fullname);
 			} else {
 				if (classptr->BuildupData != NULL) {
-					delete (ShapeSet *)classptr->BuildupData;
-					classptr->BuildupData = NULL;
+					Free_Demand_Loaded_Shape(classptr->BuildupData);
 				}
 			}
 
@@ -633,14 +638,12 @@ void BuildingTypeClass::Init(TheaterType theater)
 		} else if (classptr->IsNewTheater) {
 			if (classptr->IsDemandLoad) {
 				if (classptr->ImageData != NULL) {
-					delete (ShapeSet *)classptr->ImageData;
-					classptr->ImageData = NULL;
+					Free_Demand_Loaded_Shape(classptr->ImageData);
 				}
 			}
 			if (classptr->IsDemandLoadBuildup) {
 				if (classptr->BuildupData != NULL) {
-					delete (ShapeSet *)classptr->BuildupData;
-					classptr->BuildupData = NULL;
+					Free_Demand_Loaded_Shape(classptr->BuildupData);
 				}
 			}
 			classptr->Fetch_Building_Normal_Image(theater);
@@ -1131,6 +1134,17 @@ bool BuildingTypeClass::Read_INI(CCINIClass const & ini)
 {
 	char buffer[128];
 
+	if (!ini.Section_Present(IniName)) {
+		return(false);
+	}
+
+	if (IsDemandLoad && ImageData != NULL) {
+		Free_Demand_Loaded_Shape(ImageData);
+	}
+	if (IsDemandLoadBuildup && BuildupData != NULL) {
+		Free_Demand_Loaded_Shape(BuildupData);
+	}
+
 	if (BASECLASS::Read_INI(ini)) {
 
 		HasSpotlight = ini.Get_Bool(Name(), "HasSpotlight", HasSpotlight);
@@ -1267,6 +1281,12 @@ bool BuildingTypeClass::Read_INI(CCINIClass const & ini)
 		IsDemandLoad = ArtINI.Get_Bool(Graphic_Name(), "DemandLoad", IsDemandLoad);
 		IsDemandLoadBuildup = ArtINI.Get_Bool(Graphic_Name(), "DemandLoadBuildup", IsDemandLoadBuildup);
 		IsFreeBuildup = ArtINI.Get_Bool(Graphic_Name(), "FreeBuildup", IsFreeBuildup);
+		if (IsDemandLoad) {
+			ImageData = NULL;
+		}
+		if (IsDemandLoadBuildup) {
+			BuildupData = NULL;
+		}
 
 		OccupyList = OccupyLists[Size];
 		ExitList = ExitLists[Size];
@@ -1722,7 +1742,11 @@ void BuildingTypeClass::Post_Load(void)
 	BASECLASS::Post_Load();
 
 	Fetch_Building_Voxel_Image();
-	Fetch_Normal_Image();
+	if (IsDemandLoad) {
+		ImageData = NULL;
+	} else {
+		Fetch_Normal_Image();
+	}
 
 	ToTile = NULL;
 	OccupyList = OccupyLists[Size];
@@ -2047,10 +2071,9 @@ void const * BuildingTypeClass::Get_Buildup_Data(void) const
 /// </summary>
 void BuildingTypeClass::Free_Buildup_Data(void)
 {
-	if (IsFreeBuildup) {
+	if (IsFreeBuildup && IsDemandLoadBuildup) {
 		if (BuildupData != NULL) {
-			delete (ShapeSet *)BuildupData;
-			BuildupData = NULL;
+			Free_Demand_Loaded_Shape(BuildupData);
 		}
 	}
 }

code/overtype.cpp

@@ -77,6 +77,16 @@
 #include "tracker.h"
 
 
+/// <summary>
+/// Releases shape data that this type loaded through the file layer.
+/// </summary>
+static void Free_Demand_Loaded_Shape(void const *& data)
+{
+	delete [] (char *)data;
+	data = NULL;
+}
+
+
 /***********************************************************************************************
  * OverlayTypeClass::OverlayTypeClass -- Constructor for overlay type objects.                 *
  *                                                                                             *
@@ -133,8 +143,7 @@ OverlayTypeClass::OverlayTypeClass(char const * ininame) :
 OverlayTypeClass::~OverlayTypeClass(void)
 {
 	if (DemandLoad && ImageData != NULL) {
-		delete (ShapeSet *)ImageData;
-		ImageData = NULL;
+		Free_Demand_Loaded_Shape(ImageData);
 	}
 	Detach_This_From_All(this, true);
 	OverlayTypes.Delete(this);
@@ -301,8 +310,7 @@ void OverlayTypeClass::Init(TheaterType theater)
 		} else {
 			if (overlay.IsTheater || overlay.IsNewTheater) {
 				if (overlay.ImageData != NULL) {
-					delete [] (char*) overlay.ImageData;
-					overlay.ImageData = NULL;
+					Free_Demand_Loaded_Shape(overlay.ImageData);
 				}
 			}
 		}
@@ -321,6 +329,14 @@ bool OverlayTypeClass::Read_INI(CCINIClass const & ini)
 {
 	char fullname[_MAX_FNAME+_MAX_EXT];
 
+	if (!ini.Section_Present(IniName)) {
+		return(false);
+	}
+
+	if (DemandLoad && ImageData != NULL) {
+		Free_Demand_Loaded_Shape(ImageData);
+	}
+
 	if (BASECLASS::Read_INI(ini)) {
 		Land = ini.Get_LandType(IniName, "Land", Land);
 		DamagePoints = ini.Get_Int(IniName, "Strength", DamagePoints);
@@ -336,6 +352,9 @@ bool OverlayTypeClass::Read_INI(CCINIClass const & ini)
 
 		DamageLevels = ArtINI.Get_Int(GraphicName, "DamageLevels", DamageLevels);
 		DemandLoad = ArtINI.Get_Bool(GraphicName, "DemandLoad", DemandLoad);
+		if (DemandLoad) {
+			ImageData = NULL;
+		}
 
 		if (IsTiberium) {
 			Armor = ARMOR_WOOD;
@@ -417,9 +436,9 @@ void OverlayTypeClass::Post_Load(void)
 	BASECLASS::Post_Load();
 
 	Fetch_Voxel_Image();
-	Fetch_Normal_Image();
 
 	if (!DemandLoad) {
+		Fetch_Normal_Image();
 		char fullname[_MAX_FNAME+_MAX_EXT];
 		if (IsTheater) {
 			_makepath(fullname, NULL, NULL, GraphicName, Theaters[Scen->Theater].Suffix);
@@ -546,10 +565,9 @@ void const * OverlayTypeClass::Get_Image_Data(void) const
 	DebugString("Demand loading image for %s\n", (char const *)GivenName);
 	if (IsTheater) {
 		_makepath(fullname, NULL, NULL, GraphicName, Theaters[Scen->Theater].Suffix);
-
 	} else {
+		_makepath(fullname, NULL, NULL, GraphicName, ".SHP");
 		if (IsNewTheater) {
-			_makepath(fullname, NULL, NULL, GraphicName, ".SHP");
 			_this->Theater_Naming_Convention( fullname, Scen->Theater);
 		}
 	}

manual/changes/demand-loaded-building-art-ownership.md

@@ -0,0 +1,50 @@
+---
+title: Keep demand-loaded artwork under its owner's lifetime
+category: fix
+release: 0.2.0
+targets:
+- type: key
+  id: DemandLoad
+  scope: buildingtype
+  effect: changed
+- type: key
+  id: DemandLoad
+  scope: animtype
+  effect: changed
+- type: key
+  id: DemandLoad
+  scope: overlaytype
+  effect: changed
+- type: key
+  id: DemandLoadBuildup
+  effect: changed
+- type: key
+  id: FreeBuildup
+  effect: changed
+credit: [Krisztiaan, ZivDero]
+---
+
+A structure type with `DemandLoad=yes` now detaches the archive-owned shape found while
+reading its rules or restoring a saved game. The type loads its own copy when the shape is
+first needed and releases only that copy. A theater-aware structure previously tried to
+release the archive's shared memory during theater setup, which could stop a skirmish before
+play began.
+
+Demand-loaded structure shapes and construction animations are now released as the byte
+arrays that the file loader allocated. Their former scalar release did not match that
+allocation and could corrupt the heap during theater changes, construction-art cleanup or
+shutdown.
+
+`FreeBuildup=yes` now releases construction artwork only when `DemandLoadBuildup=yes` gave
+the structure type its own copy. On its own the setting leaves archive-owned artwork in
+place instead of freeing shared memory. Later structures retain their construction and
+deconstruction animation and sellability, and their nominal crew become technicians when
+the structure is destroyed.
+
+Demand-loaded animations and overlays now detach their archive-owned shapes after reading
+their settings and after restoring a saved game. They release only the separate copies
+loaded when first drawn, rather than handing archive memory back during theater changes or
+shutdown.
+
+An ordinary demand-loaded overlay now builds its deferred filename from its Image ID. Its
+first draw loads the `.SHP` instead of reading through an uninitialized filename.

manual/content/formats/mix.md

@@ -32,7 +32,7 @@ Whether an archive is cached decides how its members can be reached:
 - A member of a cached archive can be handed out as a pointer straight into the memory the archive is already holding. Nothing is allocated for the member and nothing is copied. Shapes, fonts, palettes and sound samples are fetched this way, so those files have to live in an archive that was cached — a loose file, or a member of an archive that was mounted without being cached, is not found by that path at all.
 - Opening a member as a file works either way. From a cached archive the file object becomes a window onto that same memory and a read copies out of it; from an archive that is not cached the archive file itself is opened and every read is biased to the member's position within it.
 
-The memory belongs to the archive rather than to whatever asked for the member, so a pointer fetched the first way stays good only while that archive stays cached and mounted, and handing it back is not something its holder may do. [`FreeBuildup`](/keys/freebuildup/) describes what a type that hands one back costs the rest of the game.
+The memory belongs to the archive rather than to whatever asked for the member, so a pointer fetched the first way stays good only while that archive stays cached and mounted, and handing it back is not something its holder may do. Demand-loaded structure, animation, overlay and construction shapes release only the separate copies they read through the file layer.
 
 :::danger[An archive too short to hold a header is mounted from uninitialized memory]
 The number of members and the size of the data block are taken from the first bytes of the file without testing that any bytes were read. An archive that cannot supply them — an empty file most obviously — is mounted with a member count and an index taken from whatever that memory last held. Allocating an index for an implausible count is not survivable; where the count is small enough to allocate, the archive joins the search carrying meaningless entries, and a request that matches one is handed an offset and a size that describe no file.

manual/content/keys/demandload--animtype.md

@@ -8,12 +8,8 @@ when_omitted:
   value: "no"
 ---
 
-The flag is read after the animation's shape has already been fetched from the archives under its [Image ID](/keys/image/#scope-animtype), so an animation whose artwork is present is holding it before the setting is consulted and nothing is deferred. What the flag then skips is the later work: the shape is not fetched again when the theater is set up, and the theater's own copy is not fetched again when a saved game is restored — though the restore does re-attach the archive's copy, which puts the release below back in reach.
+The flag is read after the animation's shape has already been found in the archives under its [Image ID](/keys/image/#scope-animtype). With the flag set, the animation type detaches that archive-owned shape without releasing it and leaves its own shape empty. Restoring a saved game also leaves the shape empty rather than attaching the archive's copy.
 
 An animation that reaches a draw with no shape reads one from disk at that moment, and the frame count and loop end the type left unset are taken from it then rather than at load time. The name built for that read is the Image ID if the animation has one and the AnimType ID otherwise, with a `.SHP` extension; a [`Theater=yes`](/keys/theater/#scope-animtype) animation instead uses the AnimType ID with the theater's own extension, dropping the Image ID, and a [`NewTheater=yes`](/keys/newtheater/#scope-animtype) one has the built name rewritten for the theater.
 
-On a `Theater=yes` or `NewTheater=yes` animation the shape the type is holding is released as the theater is set up rather than replaced. It is released with the type as well, and on a [`FreeAfterPlaying=yes`](/keys/freeafterplaying/) animation as soon as the animation finishes playing — the only combination that gives artwork back during a match.
-
-:::danger[The release hands back memory the type may never have allocated]
-Both releases run on whatever the shape pointer holds. Artwork the animation fetched for itself is a block it may give back; the pointer left by the earlier archive fetch is not, and handing that back corrupts the heap: the game may fault there or at a later, unrelated allocation.
-:::
+On a `Theater=yes` or `NewTheater=yes` animation, the separately loaded shape is released when the theater changes. It is also released with the type, and on a [`FreeAfterPlaying=yes`](/keys/freeafterplaying/) animation as soon as the animation finishes playing — the only combination that gives artwork back during a match.

manual/content/keys/demandload--buildingtype.md

@@ -8,12 +8,8 @@ when_omitted:
   value: "no"
 ---
 
-A structure's shape is fetched from the archives twice while the rules are read: once under its [Image ID](/keys/image/), before this setting has been read at all, and once afterwards under the [main-shape basename](/keys/image/#scope-buildingtype). Only the second fetch is skipped. A structure whose two names agree — the ordinary case — is therefore already holding its artwork by the time the flag is consulted, and setting it changes nothing about when the shape is loaded. Deferral takes effect only where the first name resolves to no file.
+A structure's shape is first found in the archives under its [Image ID](/keys/image/), before this setting has been read. With the flag set, the structure type detaches that archive-owned shape without releasing it, records the [main-shape basename](/keys/image/#scope-buildingtype) for the current theater, and leaves its own shape empty.
 
-Where it does take effect, the shape is read from disk the first time something asks to draw a structure of the type, and is then held for the rest of the session. A type nothing ever draws allocates nothing, and a structure whose shape cannot be found is not drawn at all.
+The shape is read from disk the first time something asks to draw a structure of the type. It is released when that type's rules section is read again, when theater setup revisits a `Theater=yes` or `NewTheater=yes` type, or when the type is destroyed. A type nothing ever draws allocates nothing, and a structure whose shape cannot be found is not drawn at all.
 
 The construction animation is a separate setting, [`DemandLoadBuildup`](/keys/demandloadbuildup/). The deploying, door, under-door, bib and Z-shape overlay artwork is fetched with the rules whatever this is set to.
-
-:::danger[The release hands back memory the type may never have allocated]
-A type carrying this flag releases whatever its shape pointer holds when the type is destroyed, and again as the theater is set up if the type is also [`Theater=yes`](/keys/theater/) or [`NewTheater=yes`](/keys/newtheater/). Only a shape this flag actually deferred is a block the type allocated for itself; the pointer left by the earlier fetch belongs to the archive it was read from, and handing that back corrupts the heap: the game may fault there or at a later, unrelated allocation.
-:::