[svn-r13753] Description:

	Check in "unique, but sharable" optimization to ISOHM code, which
allows object header messages that are only used in one object to remain in
the sole user's header, but migrates messages that are used in more than one
header into the ISOHM heap.

Tested on:
	Mac OS X/32 10.4.9 (amazon)
	FreeBSD/32 6.2 (duty)
	Linux/32 2.6 (chicago)
	Linux/64 2.6 (chicago2)

1 files changed, 27 insertions, 19 deletions

diff --git a/src/H5Oattribute.c b/src/H5Oattribute.c
index 45c1f8a..ddf5a35 100644
--- a/src/H5Oattribute.c
+++ b/src/H5Oattribute.c
@@ -368,7 +368,7 @@ H5O_attr_create(const H5O_loc_t *loc, hid_t dxpl_id, H5A_t *attr)
          *      *ick* -QAK, 2007/01/08
          */
         if(attr_rc > 1) {
-            if(H5O_attr_delete(loc->file, dxpl_id, attr) < 0)
+            if(H5O_attr_delete(loc->file, dxpl_id, oh, attr) < 0)
                 HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute")
         } /* end if */
     } /* end if */
@@ -598,7 +598,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5O_attr_update_shared(H5F_t *f, hid_t dxpl_id, H5A_t *attr,
+H5O_attr_update_shared(H5F_t *f, hid_t dxpl_id, H5O_t *oh, H5A_t *attr,
     H5O_shared_t *update_sh_mesg)
 {
     H5O_shared_t sh_mesg;               /* Shared object header message */
@@ -613,12 +613,16 @@ H5O_attr_update_shared(H5F_t *f, hid_t dxpl_id, H5A_t *attr,
     HDassert(attr);
 
     /* Extract shared message info from current attribute (for later use) */
-    if(H5O_shared_copy(&sh_mesg, &(attr->sh_loc)) < 0)
+    if(H5O_set_shared(&sh_mesg, &(attr->sh_loc)) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, FAIL, "can't get shared message")
 
+    /* Reset existing sharing information */
+    if(H5O_msg_reset_share(H5O_ATTR_ID, attr) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to reset attribute sharing")
+
     /* Store new version of message as a SOHM */
     /* (should always work, since we're not changing the size of the attribute) */
-    if((shared_mesg = H5SM_try_share(f, dxpl_id, H5O_ATTR_ID, attr)) == 0)
+    if((shared_mesg = H5SM_try_share(f, dxpl_id, oh, H5O_ATTR_ID, attr, NULL)) == 0)
         HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, FAIL, "attribute changed sharing status")
     else if(shared_mesg < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_BADMESG, FAIL, "can't share attribute")
@@ -630,23 +634,25 @@ H5O_attr_update_shared(H5F_t *f, hid_t dxpl_id, H5A_t *attr,
     /* If the newly shared attribute needs to share "ownership" of the shared
      *      components (ie. its reference count is 1), increment the reference
      *      count on any shared components of the attribute, so that they won't
-     *      be removed from the file.  (Essentially a "copy on write" operation).
+     *      be removed from the file by the following "delete" operation on the
+     *      original attribute shared message info.  (Essentially a "copy on
+     *      write" operation).
      *
      *      *ick* -QAK, 2007/01/08
      */
     if(attr_rc == 1) {
         /* Increment reference count on attribute components */
-        if(H5O_attr_link(f, dxpl_id, attr) < 0)
+        if(H5O_attr_link(f, dxpl_id, oh, attr) < 0)
             HGOTO_ERROR(H5E_ATTR, H5E_LINKCOUNT, FAIL, "unable to adjust attribute link count")
     } /* end if */
 
     /* Remove the old attribute from the SOHM storage */
-    if(H5SM_try_delete(f, dxpl_id, H5O_ATTR_ID, &sh_mesg) < 0)
+    if(H5SM_delete(f, dxpl_id, oh, &sh_mesg) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTFREE, FAIL, "unable to delete shared attribute in shared storage")
 
     /* Extract updated shared message info from modified attribute, if requested */
     if(update_sh_mesg)
-        if(H5O_shared_copy(update_sh_mesg, &(attr->sh_loc)) < 0)
+        if(H5O_set_shared(update_sh_mesg, &(attr->sh_loc)) < 0)
             HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, FAIL, "can't get shared message")
 
 done:
@@ -669,7 +675,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_attr_write_cb(H5O_t UNUSED *oh, H5O_mesg_t *mesg/*in,out*/,
+H5O_attr_write_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
     unsigned UNUSED sequence, hbool_t *oh_modified, void *_udata/*in,out*/)
 {
     H5O_iter_wrt_t *udata = (H5O_iter_wrt_t *)_udata;   /* Operator user data */
@@ -684,20 +690,22 @@ H5O_attr_write_cb(H5O_t UNUSED *oh, H5O_mesg_t *mesg/*in,out*/,
 
     /* Check for correct attribute message to modify */
     if(HDstrcmp(((H5A_t *)mesg->native)->name, udata->attr->name) == 0) {
-        /* Update the shared attribute in the SOHM storage */
-        if(mesg->flags & H5O_MSG_FLAG_SHARED) {
-            if(H5O_attr_update_shared(udata->f, udata->dxpl_id, udata->attr, (H5O_shared_t *)mesg->native) < 0)
-                HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, H5_ITER_ERROR, "unable to update attribute in shared storage")
-        } /* end if */
-
         /* Allocate storage for the message's data, if necessary */
         if(((H5A_t *)mesg->native)->data == NULL)
             if(NULL == (((H5A_t *)mesg->native)->data = H5FL_BLK_MALLOC(attr_buf, udata->attr->data_size)))
                 HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, H5_ITER_ERROR, "memory allocation failed")
 
         /* Copy the data into the header message */
+        /* (Needs to occur before updating the shared message, or the hash
+         *      value on the old & new messages will be the same)
+         */
         HDmemcpy(((H5A_t *)mesg->native)->data, udata->attr->data, udata->attr->data_size);
 
+        /* Update the shared attribute in the SOHM storage */
+        if(mesg->flags & H5O_MSG_FLAG_SHARED)
+            if(H5O_attr_update_shared(udata->f, udata->dxpl_id, oh, udata->attr, (H5O_shared_t *)mesg->native) < 0)
+                HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, H5_ITER_ERROR, "unable to update attribute in shared storage")
+
         /* Mark message as dirty */
         mesg->dirty = TRUE;
 
@@ -880,7 +888,7 @@ H5O_attr_rename_mod_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/,
         /* Check for shared message */
         if(mesg->flags & H5O_MSG_FLAG_SHARED) {
             /* Update the shared attribute in the SOHM storage */
-            if(H5O_attr_update_shared(udata->f, udata->dxpl_id, mesg->native, NULL) < 0)
+            if(H5O_attr_update_shared(udata->f, udata->dxpl_id, oh, mesg->native, NULL) < 0)
                 HGOTO_ERROR(H5E_ATTR, H5E_CANTUPDATE, H5_ITER_ERROR, "unable to update attribute in shared storage")
         } /* end if */
         else {
@@ -1214,12 +1222,12 @@ H5O_attr_remove_update(const H5O_loc_t *loc, H5O_t *oh, H5O_ainfo_t *ainfo,
                 else if(shared_mesg == 0) {
                     /* Increment reference count on attribute components */
                     /* (so that they aren't deleted when the dense attribute storage is deleted) */
-                    if(H5O_attr_link(loc->file, dxpl_id, &(atable.attrs[u])) < 0)
+                    if(H5O_attr_link(loc->file, dxpl_id, oh, &(atable.attrs[u])) < 0)
                         HGOTO_ERROR(H5E_ATTR, H5E_LINKCOUNT, FAIL, "unable to adjust attribute link count")
                 } /* end if */
                 else {
-                    /* Reset 'shared' status, so attributes will be shared again */
-                    atable.attrs[u].sh_loc.flags = 0;
+                    /* Reset 'shared' status, so attribute will be shared again */
+                    atable.attrs[u].sh_loc.type = H5O_SHARE_TYPE_UNSHARED;
                 } /* end else */
 
                 /* Insert attribute message into object header */