gpg: Add push/pop found state feature to keydb.

* g10/keydb.c (keydb_handle): Add field saved_found.
(keydb_new): Init new field.
(keydb_push_found_state, keydb_pop_found_state): New.
* g10/keyring.c (kyring_handle): Add field saved_found.
(keyring_push_found_state, keyring_pop_found_state): New.
--

We have the same feature in gpgsm.  It is very useful to check for an
unambiguous user id with a follow up update of the keyblock.

Signed-off-by: Werner Koch <wk@gnupg.org>

g10/keydb.c

@@ -1,7 +1,6 @@
 /* keydb.c - key database dispatcher
- * Copyright (C) 2001, 2002, 2003, 2004, 2005,
- *               2008, 2009, 2011, 2013 Free Software Foundation, Inc.
- * Coyrright (C) 2013 Werner Koch
+ * Copyright (C) 2001-2013 Free Software Foundation, Inc.
+ * Coyrright (C) 2001-2015 Werner Koch
  *
  * This file is part of GnuPG.
  *
@@ -67,6 +66,7 @@ struct keydb_handle
 {
   int locked;
   int found;
+  int saved_found;
   unsigned long skipped_long_blobs;
   int no_caching;
   int current;
@@ -542,6 +542,7 @@ keydb_new (void)
 
   hd = xmalloc_clear (sizeof *hd);
   hd->found = -1;
+  hd->saved_found = -1;
 
   assert (used_resources <= MAX_KEYDB_RESOURCES);
   for (i=j=0; i < used_resources; i++)
@@ -741,6 +742,64 @@ unlock_all (KEYDB_HANDLE hd)
 }
 
 
+
+/* Push the last found state if any.  */
+void
+keydb_push_found_state (KEYDB_HANDLE hd)
+{
+  if (!hd)
+    return;
+
+  if (hd->found < 0 || hd->found >= hd->used)
+    {
+      hd->saved_found = -1;
+      return;
+    }
+
+  switch (hd->active[hd->found].type)
+    {
+    case KEYDB_RESOURCE_TYPE_NONE:
+      break;
+    case KEYDB_RESOURCE_TYPE_KEYRING:
+      keyring_push_found_state (hd->active[hd->found].u.kr);
+      break;
+    case KEYDB_RESOURCE_TYPE_KEYBOX:
+      keybox_push_found_state (hd->active[hd->found].u.kb);
+      break;
+    }
+
+  hd->saved_found = hd->found;
+  hd->found = -1;
+}
+
+
+/* Pop the last found state.  */
+void
+keydb_pop_found_state (KEYDB_HANDLE hd)
+{
+  if (!hd)
+    return;
+
+  hd->found = hd->saved_found;
+  hd->saved_found = -1;
+  if (hd->found < 0 || hd->found >= hd->used)
+    return;
+
+  switch (hd->active[hd->found].type)
+    {
+    case KEYDB_RESOURCE_TYPE_NONE:
+      break;
+    case KEYDB_RESOURCE_TYPE_KEYRING:
+      keyring_pop_found_state (hd->active[hd->found].u.kr);
+      break;
+    case KEYDB_RESOURCE_TYPE_KEYBOX:
+      keybox_pop_found_state (hd->active[hd->found].u.kb);
+      break;
+    }
+}
+
+
+
 static gpg_error_t
 parse_keyblock_image (iobuf_t iobuf, int pk_no, int uid_no,
                       const u32 *sigstatus, kbnode_t *r_keyblock)

g10/keydb.h

@@ -136,6 +136,8 @@ gpg_error_t keydb_add_resource (const char *url, unsigned int flags);
 KEYDB_HANDLE keydb_new (void);
 void keydb_release (KEYDB_HANDLE hd);
 void keydb_disable_caching (KEYDB_HANDLE hd);
+void keydb_push_found_state (KEYDB_HANDLE hd);
+void keydb_pop_found_state (KEYDB_HANDLE hd);
 const char *keydb_get_resource_name (KEYDB_HANDLE hd);
 gpg_error_t keydb_get_keyblock (KEYDB_HANDLE hd, KBNODE *ret_kb);
 gpg_error_t keydb_update_keyblock (KEYDB_HANDLE hd, kbnode_t kb);

g10/keyring.c

@@ -1,5 +1,6 @@
 /* keyring.c - keyring file handling
- * Copyright (C) 2001, 2004, 2009, 2010 Free Software Foundation, Inc.
+ * Copyright (C) 1998-2010 Free Software Foundation, Inc.
+ * Copyright (C) 1997-2015 Werner Koch
  *
  * This file is part of GnuPG.
  *
@@ -83,7 +84,7 @@ struct keyring_handle
     size_t pk_no;
     size_t uid_no;
     unsigned int n_packets; /*used for delete and update*/
-  } found;
+  } found, saved_found;
   struct {
     char *name;
     char *pattern;
@@ -279,6 +280,25 @@ keyring_release (KEYRING_HANDLE hd)
 }
 
 
+/* Save the current found state in HD for later retrieval by
+   keybox_pop_found_state.  Only one state may be saved.  */
+void
+keyring_push_found_state (KEYRING_HANDLE hd)
+{
+  hd->saved_found = hd->found;
+  hd->found.kr = NULL;
+}
+
+
+/* Restore the saved found state in HD.  */
+void
+keyring_pop_found_state (KEYRING_HANDLE hd)
+{
+  hd->found = hd->saved_found;
+  hd->saved_found.kr = NULL;
+}
+
+
 const char *
 keyring_get_resource_name (KEYRING_HANDLE hd)
 {

g10/keyring.h

@@ -29,6 +29,8 @@ int keyring_is_writable (void *token);
 
 KEYRING_HANDLE keyring_new (void *token);
 void keyring_release (KEYRING_HANDLE hd);
+void keyring_push_found_state (KEYRING_HANDLE hd);
+void keyring_pop_found_state (KEYRING_HANDLE hd);
 const char *keyring_get_resource_name (KEYRING_HANDLE hd);
 int keyring_lock (KEYRING_HANDLE hd, int yes);
 int keyring_get_keyblock (KEYRING_HANDLE hd, KBNODE *ret_kb);