From aaaf1acc08846684af8750db68cdf6d02bbc540f Mon Sep 17 00:00:00 2001
From: Quincey Koziol <koziol@hdfgroup.org>
Date: Mon, 29 Oct 2018 16:52:00 -0500
Subject: Add ref counter to VOL object wrapping in API contexts, so that
 re-entrant / recursive routines work correctly.  Another minor cleanup in the
 attribute code.

---
 src/H5Aint.c  |  2 +-
 src/H5VLint.c | 75 +++++++++++++++++++++++++++++++++++++++++------------------
 2 files changed, 54 insertions(+), 23 deletions(-)

diff --git a/src/H5Aint.c b/src/H5Aint.c
index 97da9a4..8d90cf9 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -2628,7 +2628,7 @@ H5A__iterate(const H5G_loc_t *loc, const char *obj_name, H5_index_t idx_type, H5
     H5G_name_t  obj_path;       /* Opened object group hier. path */
     H5O_loc_t   obj_oloc;       /* Opened object object location */
     hbool_t     loc_found = FALSE;      /* Entry at 'obj_name' found */
-    hid_t       obj_loc_id = (-1);      /* ID for object located */
+    hid_t       obj_loc_id = H5I_INVALID_HID;      /* ID for object located */
     H5A_attr_iter_op_t  attr_op;        /* Attribute operator */
     void        *temp_obj = NULL;
     H5I_type_t  obj_type;
diff --git a/src/H5VLint.c b/src/H5VLint.c
index b00355d..e6e0dbe 100644
--- a/src/H5VLint.c
+++ b/src/H5VLint.c
@@ -50,6 +50,7 @@
 
 /* Object wrapping context info */
 typedef struct H5VL_wrap_ctx_t {
+    unsigned rc;                /* Ref. count for the # of times the context was set / reset */
     const H5VL_t *plugin;       /* VOL plugin for "outermost" class to start wrap */
     void *obj_wrap_ctx;         /* "wrap context" for outermost plugin */
 } H5VL_wrap_ctx_t;
@@ -857,23 +858,34 @@ H5VL_set_vol_wrapper(void *obj, const H5VL_t *plugin)
     HDassert(obj);
     HDassert(plugin);
 
-    /* Check if the plugin can create a wrap context */
-    if(plugin->cls->get_wrap_ctx) {
-        /* Sanity check */
-        HDassert(plugin->cls->free_wrap_ctx);
+    /* Retrieve the VOL object wrap context */
+    if(H5CX_get_vol_wrap_ctx((void **)&vol_wrap_ctx) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get VOL object wrap context")
 
-        /* Get the wrap context from the plugin */
-        if((plugin->cls->get_wrap_ctx)(obj, &obj_wrap_ctx) < 0)
-            HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't retrieve VOL plugin's object wrap context")
-    } /* end if */
+    /* Check for existing wrapping context */
+    if(NULL == vol_wrap_ctx) {
+        /* Check if the plugin can create a wrap context */
+        if(plugin->cls->get_wrap_ctx) {
+            /* Sanity check */
+            HDassert(plugin->cls->free_wrap_ctx);
 
-    /* Allocate VOL object wrapper context */
-    if(NULL == (vol_wrap_ctx = H5FL_MALLOC(H5VL_wrap_ctx_t)))
-        HGOTO_ERROR(H5E_VOL, H5E_CANTALLOC, FAIL, "can't allocate VOL wrap context")
+            /* Get the wrap context from the plugin */
+            if((plugin->cls->get_wrap_ctx)(obj, &obj_wrap_ctx) < 0)
+                HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't retrieve VOL plugin's object wrap context")
+        } /* end if */
+
+        /* Allocate VOL object wrapper context */
+        if(NULL == (vol_wrap_ctx = H5FL_MALLOC(H5VL_wrap_ctx_t)))
+            HGOTO_ERROR(H5E_VOL, H5E_CANTALLOC, FAIL, "can't allocate VOL wrap context")
 
-    /* Set up VOL object wrapper context */
-    vol_wrap_ctx->plugin = plugin;
-    vol_wrap_ctx->obj_wrap_ctx = obj_wrap_ctx;
+        /* Set up VOL object wrapper context */
+        vol_wrap_ctx->rc = 1;;
+        vol_wrap_ctx->plugin = plugin;
+        vol_wrap_ctx->obj_wrap_ctx = obj_wrap_ctx;
+    } /* end if */
+    else
+        /* Incremeent ref count on existing wrapper context */
+        vol_wrap_ctx->rc++;
 
     /* Save the wrapper context */
     if(H5CX_set_vol_wrap_ctx(vol_wrap_ctx) < 0)
@@ -909,15 +921,34 @@ H5VL_reset_vol_wrapper(void)
     if(H5CX_get_vol_wrap_ctx((void **)&vol_wrap_ctx) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get VOL object wrap context")
 
-    /* If there is a VOL plugin object wrapping context, release it */
-    if(vol_wrap_ctx->obj_wrap_ctx) {
-        /* Release the VOL plugin's object wrapping context */
-        if((*vol_wrap_ctx->plugin->cls->free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
-            HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release plugin's object wrapping context")
-    } /* end if */
+    /* Check for VOL object wrap context */
+    if(NULL == vol_wrap_ctx)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "no VOL object wrap context?")
+
+    /* Decrement ref count on wrapping context */
+    vol_wrap_ctx->rc--;
+
+    /* Release context if the ref count drops to zero */
+    if(0 == vol_wrap_ctx->rc) {
+        /* If there is a VOL plugin object wrapping context, release it */
+        if(vol_wrap_ctx->obj_wrap_ctx) {
+            /* Release the VOL plugin's object wrapping context */
+            if((*vol_wrap_ctx->plugin->cls->free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
+                HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release plugin's object wrapping context")
+        } /* end if */
 
-    /* Release object wrapping context */
-    H5FL_FREE(H5VL_wrap_ctx_t, vol_wrap_ctx);
+        /* Release object wrapping context */
+        H5FL_FREE(H5VL_wrap_ctx_t, vol_wrap_ctx);
+
+        /* Reset the wrapper context */
+        if(H5CX_set_vol_wrap_ctx(NULL) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL object wrap context")
+    } /* end if */
+    else {
+        /* Save the updated wrapper context */
+        if(H5CX_set_vol_wrap_ctx(vol_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL object wrap context")
+    } /* end else */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-- 
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