[PATCH v2] msacm32: Reference count local drivers.

[Zhiyi Zhang]

One local driver can be assigned to multiple driver ids.
When releasing the driver id, check if the reference count
of a local driver is one before actually releasing the local driver.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=46520
Signed-off-by: Zhiyi Zhang 
Signed-off-by: Andrew Eikum 
---
v2: Add Wine-Bug tag.

dlls/msacm32/internal.c | 12 +++++++++++-
 dlls/msacm32/wineacm.h  |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/dlls/msacm32/internal.c b/dlls/msacm32/internal.c
index aad071e8ad..7d324a8b27 100644
--- a/dlls/msacm32/internal.c
+++ b/dlls/msacm32/internal.c
@@ -737,12 +737,17 @@ static PWINE_ACMLOCALDRIVER MSACM_pLastACMLocalDriver;
 static PWINE_ACMLOCALDRIVER MSACM_UnregisterLocalDriver(PWINE_ACMLOCALDRIVER paldrv)
 {
     PWINE_ACMLOCALDRIVER pNextACMLocalDriver;
+    LONG ref;

if (paldrv->pACMInstList) {
         ERR("local driver instances still present after closing all drivers - memory leak\n");
         return NULL;
     }

+    ref = InterlockedDecrement(&paldrv->ref);
+    if (ref)
+        return paldrv;
+
     if (paldrv == MSACM_pFirstACMLocalDriver)
         MSACM_pFirstACMLocalDriver = paldrv->pNextACMLocalDrv;
     if (paldrv == MSACM_pLastACMLocalDriver)
@@ -883,7 +888,11 @@ PWINE_ACMLOCALDRIVER MSACM_RegisterLocalDriver(HMODULE hModule, DRIVERPROC lpDri
     /* look up previous instance of local driver module */
     for (paldrv = MSACM_pFirstACMLocalDriver; paldrv; paldrv = paldrv->pNextACMLocalDrv)
     {
-        if (paldrv->hModule == hModule && paldrv->lpDrvProc == lpDriverProc) return paldrv;
+        if (paldrv->hModule == hModule && paldrv->lpDrvProc == lpDriverProc)
+        {
+            InterlockedIncrement(&paldrv->ref);
+            return paldrv;
+        }
     }

paldrv = HeapAlloc(MSACM_hHeap, 0, sizeof(WINE_ACMLOCALDRIVER));
@@ -892,6 +901,7 @@ PWINE_ACMLOCALDRIVER MSACM_RegisterLocalDriver(HMODULE hModule, DRIVERPROC lpDri
     paldrv->hModule = hModule;
     paldrv->lpDrvProc = lpDriverProc;
     paldrv->pACMInstList = NULL;
+    paldrv->ref = 1;

paldrv->pNextACMLocalDrv = NULL;
     paldrv->pPrevACMLocalDrv = MSACM_pLastACMLocalDriver;
diff --git a/dlls/msacm32/wineacm.h b/dlls/msacm32/wineacm.h
index 406e01bf21..98d1ab5a2c 100644
--- a/dlls/msacm32/wineacm.h
+++ b/dlls/msacm32/wineacm.h
@@ -52,6 +52,7 @@ typedef struct _WINE_ACMLOCALDRIVER
     PWINE_ACMLOCALDRIVERINST pACMInstList;
     PWINE_ACMLOCALDRIVER pNextACMLocalDrv;
     PWINE_ACMLOCALDRIVER pPrevACMLocalDrv;
+    LONG                ref;
 } WINE_ACMLOCALDRIVER;

typedef struct _WINE_ACMLOCALDRIVERINST