[svn-r12528] Added User-Defined links to the library.

Users can create external links using H5L_create_external().  These links
point to an object in another HDF5 file.  Users can alter the behavior of
external links or create new kinds of links by registering callbacks
using the H5L interface.

Added tests, tools support, etc.

Also a number of other, minor changes have been made (some restructuring of
the H5L interface, for instance).

Additional documentation and examples are forthcoming.

1 files changed, 60 insertions, 5 deletions

diff --git a/tools/h5ls/h5ls.c b/tools/h5ls/h5ls.c
index d279ea3..9a51ce2 100644
--- a/tools/h5ls/h5ls.c
+++ b/tools/h5ls/h5ls.c
@@ -1710,7 +1710,7 @@ datatype_list2(hid_t type, const char UNUSED *name)
 
 
 /*-------------------------------------------------------------------------
- * Function: link_open
+ * Function: slink_open
  *
  * Purpose: This gets called to open a symbolic link.  Since symbolic
  *  links don't correspond to actual objects we simply print the
@@ -1729,11 +1729,11 @@ datatype_list2(hid_t type, const char UNUSED *name)
  *-------------------------------------------------------------------------
  */
 static hid_t
-link_open(hid_t location, const char *name)
+slink_open(hid_t location, const char *name)
 {
     char buf[64];
 
-    if (H5Gget_linkval (location, name, sizeof(buf), buf)<0) return -1;
+    if (H5Lget_linkval (location, name, sizeof(buf), buf, H5P_DEFAULT)<0) return -1;
     if (NULL==HDmemchr(buf, 0, sizeof(buf))) {
  strcpy(buf+sizeof(buf)-4, "...");
     }
@@ -1741,6 +1741,59 @@ link_open(hid_t location, const char *name)
 
     return 0;
 }
+/*-------------------------------------------------------------------------
+ * Function: udlink_open
+ *
+ * Purpose: This gets called to open a user-defined link.  Since these
+ *  links don't correspond to actual objects we simply print a message
+ *  and return failure.
+ *
+ * Return: Success: 0 - an invalid object but successful return
+ *    of this function.
+ *
+ *  Failure: -1
+ *
+ * Programmer: James Laird
+ *              Tuesday, June 6, 2006
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static hid_t
+udlink_open(hid_t location, const char *name)
+{
+    H5L_linkinfo_t linfo;
+    char * buf = NULL;
+    char * filename = NULL;
+    char * path = NULL;
+
+    if(H5Lget_linkinfo(location, name, &linfo, H5P_DEFAULT) < 0) return -1;
+
+    switch(linfo.linkclass)
+    {
+      /* For external links, try to display info for the object it points to */
+      case H5L_LINK_EXTERNAL:
+        if ((buf = HDmalloc(linfo.u.link_size))==NULL) goto error;
+        if (H5Lget_linkval (location, name, sizeof(buf), buf, H5P_DEFAULT)<0) goto error;
+
+        if(H5Lunpack_elink_val(buf, &filename, &path) < 0) goto error;
+        fputs("file: ", stdout);
+        fputs(filename, stdout);
+        fputs("    path: ", stdout);
+        fputs(path, stdout);
+        break;
+
+      default:
+        fputs("cannot follow UD links", stdout);
+    }
+    return 0;
+
+error:
+    if(buf)
+      HDfree(buf);
+    return -1;
+}
 
 
 /*-------------------------------------------------------------------------
@@ -1828,7 +1881,7 @@ list (hid_t group, const char *name, void *_iter)
 
     /* Show detailed information about the object, beginning with information
      * which is common to all objects. */
-    if (verbose_g>0 && H5G_LINK!=sb.type) {
+    if (verbose_g>0 && H5G_LINK!=sb.type && H5G_UDLINK!=sb.type) {
         if (sb.type>=0)
             H5Aiterate(obj, NULL, list_attr, NULL);
         printf("    %-10s %lu:"H5_PRINTF_HADDR_FMT"\n", "Location:", sb.fileno[0], objno);
@@ -2063,7 +2116,9 @@ main (int argc, const char *argv[])
       NULL, group_list2);
     DISPATCH(H5G_TYPE, "Type", H5Topen, H5Tclose,
       NULL, datatype_list2);
-    DISPATCH(H5G_LINK, "-> ", link_open, NULL,
+    DISPATCH(H5G_LINK, "-> ", slink_open, NULL,
+      NULL, NULL);
+    DISPATCH(H5G_UDLINK, "-> ", udlink_open, NULL,
       NULL, NULL);
 
 #if 0