Correctly display MIME headers read from the underlying db in virtual db

* NEWS: Update.
* doc/libdico.texi: Update.
* dicod/database.c (dicod_database_mime_header): Use temporary storage
to preserve original header in case of failure.
* dicod/virtual.c (dico_result_headers): Implement function.
* include/dico/assoc.h (dico_assoc_count): New function.
* lib/assoc.c (dico_assoc_count): New function.

6 files changed, 89 insertions, 12 deletions

diff --git a/NEWS b/NEWS
index afe09f2..7f2166f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,4 @@
-GNU Dico NEWS -- history of user-visible changes. 2018-09-06
+GNU Dico NEWS -- history of user-visible changes. 2018-09-07
 Copyright (C) 2008-2010, 2012-2018 Sergey Poznyakoff
 See the end of file for copying conditions.
 
@@ -31,9 +31,9 @@ detailed discussion.
 
 Debian-based systems provide a package "wordnet-dev", which contains
 a properly built shared wordnet library.  However, this library is named
-"libwordnet.so", instead of the expected "libWN.so".  Use the
---with-libWN option to configure, in order to inform it about the
-change, e.g.:
+"libwordnet.so", instead of the expected "libWN.so".  Due to this
+change, configure was unable to locate the library and wordnet module
+was not build.  To fix this. use the --with-libWN option, e.g.:
 
   ./configure --with-libWN=wordnet
 
diff --git a/dicod/database.c b/dicod/database.c
index 34682b8..46c57f5 100644
--- a/dicod/database.c
+++ b/dicod/database.c
@@ -233,8 +233,15 @@ dicod_database_mime_header(dicod_database_t *db, dico_result_t res)
     else
 	dico_header_parse(&hdr, NULL);
     
-    if (mod->dico_result_headers)
-	mod->dico_result_headers(res, hdr);
+    if (mod->dico_result_headers) {
+	dico_assoc_list_t tmp = dico_assoc_dup(hdr);
+	if (mod->dico_result_headers(res, tmp) == 0) {
+	    dico_assoc_destroy(&hdr);
+	    hdr = tmp;
+	} else {
+	    dico_assoc_destroy(&tmp);
+	}
+    }
 
     return hdr;
 }
diff --git a/dicod/virtual.c b/dicod/virtual.c
index 3352c0f..84d98cb 100644
--- a/dicod/virtual.c
+++ b/dicod/virtual.c
@@ -24,11 +24,6 @@ struct virtual_database {
     struct vdb_member vdb_memb[1];
 };
 
-struct vdb_result {
-    dicod_database_t *db;
-    dico_result_t res;
-};
-
 struct virtual_result {
     struct virtual_database *vdb;
     dico_result_t vdres[1];
@@ -287,6 +282,45 @@ virtual_free_result(dico_result_t rp)
     free(rp);
 }
 
+static int
+virtual_result_headers(dico_result_t rp, dico_assoc_list_t hdr)
+{  
+    struct virtual_result *result = (struct virtual_result *)rp;
+    size_t i;
+    int err = 0;
+    for (i = 0; i < result->vdb->vdb_count; i++) {
+	if (result->vdres[i]) {
+	    dico_assoc_list_t rhdr =
+		dicod_database_mime_header(result->vdb->vdb_memb[i].db,
+					   result->vdres[i]);
+	    if (rhdr) {
+		struct dico_assoc *p;
+		dico_iterator_t itr;
+
+		if (dico_assoc_count(rhdr) == 0) {
+		    err = 1;
+		    break;
+		}
+		
+		itr = dico_assoc_iterator(rhdr);
+		for (p = dico_iterator_first(itr); p;
+		     p = dico_iterator_next(itr)) {
+		    if (dico_assoc_append(hdr, p->key, p->value)) {
+			err = 1;
+			break;
+		    }
+		}
+		dico_iterator_destroy(&itr);
+		dico_assoc_destroy(&rhdr);
+	    } else
+		err = 1;
+	}
+	if (err)
+	    return err;
+    }
+    return 0;
+}
+
 struct dico_database_module virtual_builtin_module = {
     .dico_version        =  DICO_MODULE_VERSION,
     .dico_capabilities   =  DICO_CAPA_INIT_EXT,
@@ -299,5 +333,6 @@ struct dico_database_module virtual_builtin_module = {
     .dico_result_count   =  virtual_result_count,
     .dico_compare_count  =  virtual_compare_count,
     .dico_free_result    =  virtual_free_result,
-    .dico_db_flags       =  virtual_db_flags
+    .dico_db_flags       =  virtual_db_flags,
+    .dico_result_headers =  virtual_result_headers
 };
diff --git a/doc/libdico.texi b/doc/libdico.texi
index 7c66afd..39e3f4a 100644
--- a/doc/libdico.texi
+++ b/doc/libdico.texi
@@ -224,21 +224,47 @@ struct dico_assoc @{
 @deftypefn Function dico_assoc_list_t dico_assoc_create (void)
 @end deftypefn
 
+@deftypefn Function dico_assoc_list_t dico_assoc_dup(dico_assoc_list_t @var{src})
+@end deftypefn
+
 @deftypefn Function void dico_assoc_destroy (dico_assoc_list_t *@var{passoc})
 @end deftypefn
 
+@deftypefn int dico_assoc_clear(dico_assoc_list_t @var{assoc})
+@end deftypefn
+
 @deftypefn Function int dico_assoc_add (dico_assoc_list_t @var{assoc}, @
   const char *@var{key}, const char *@var{value})
 @end deftypefn
 
+@deftypefn Function int dico_assoc_append(dico_assoc_list_t @var{assoc}, @
+  const char *@var{key}, const char *@var{value})
+@end deftypefn
+
+@deftypefn Function {const char *}dico_assoc_find_n(@
+  dico_assoc_list_t @var{assoc}, @
+  const char *@var{key}, size_t @var{n})
+@end deftypefn
+  
 @deftypefn Function {const char *} dico_assoc_find (@
    dico_assoc_list_t @var{assoc},  const char *@var{key})
 @end deftypefn
 
+@deftypefn Function void dico_assoc_remove_n(@
+   dico_assoc_list_t @var{assoc}, const char *@var{key}, size_t @var{n})
+@end deftypefn
+   
 @deftypefn Function void dico_assoc_remove (@
    dico_assoc_list_t @var{assoc}, const char *@var{key})
 @end deftypefn
 
+@deftypefn Function size_t dico_assoc_count(dico_assoc_list_t @var{assoc})
+@end deftypefn
+
+@deftypefn Function dico_iterator_t dico_assoc_iterator(@
+   dico_assoc_list_t @var{assoc})
+@end deftypefn
+   
 @node diag
 @section Diagnostics Functions
 @UNREVISED
diff --git a/include/dico/assoc.h b/include/dico/assoc.h
index c0e846d..a0bc71f 100644
--- a/include/dico/assoc.h
+++ b/include/dico/assoc.h
@@ -43,6 +43,7 @@ const char *dico_assoc_find_n(dico_assoc_list_t assoc, const char *key,
 const char *dico_assoc_find(dico_assoc_list_t assoc, const char *key);
 void dico_assoc_remove_n(dico_assoc_list_t assoc, const char *key, size_t n);
 void dico_assoc_remove(dico_assoc_list_t assoc, const char *key);
+size_t dico_assoc_count(dico_assoc_list_t assoc);
 
 dico_iterator_t dico_assoc_iterator(dico_assoc_list_t assoc);
 
diff --git a/lib/assoc.c b/lib/assoc.c
index 8880129..5f82898 100644
--- a/lib/assoc.c
+++ b/lib/assoc.c
@@ -233,3 +233,11 @@ dico_assoc_iterator(dico_assoc_list_t assoc)
 	return NULL;
     return dico_list_iterator(assoc->list);
 }
+
+size_t
+dico_assoc_count(dico_assoc_list_t assoc)
+{
+    if (!assoc)
+	return 0;
+    return dico_list_count(assoc->list);
+}