[Helper] Quick and dirty string replacer with optional keys block.

First (quick and dirty) version of a more advanced key replacer where
sets of text are only outputted if the contained key matches.

include/helper.h

@@ -336,5 +336,21 @@ void parse_ranges ( char *input, rofi_range_pair **list, unsigned int *length );
  * @param filter
  */
 void rofi_output_formatted_line ( const char *format, const char *string, int selected_line, const char *filter );
+
+
+/**
+ * @param string The string with elements to be replaced
+ * @param ...    Set of {key}, value that will be replaced, terminated by  a NULL
+ *
+ * Items {key} are replaced by the value if '{key}' is passed as key/value pair, otherwise removed from string.
+ * If the {key} is in between []  all the text between [] are removed if {key}
+ * is not found. Otherwise key is replaced and [ & ] removed.
+ *
+ * This allows for optional replacement, f.e.   '{ssh-client} [-t  {title}] -e
+ * "{cmd}"' the '-t {title}' is only there if {title} is set.
+ *
+ * @returns a new string with the keys replaced.
+ */
+char *helper_string_replace_if_exists ( char * string, ... );
 G_END_DECLS
 #endif // ROFI_HELPER_H

source/helper.c

@@ -1233,3 +1233,95 @@ void rofi_output_formatted_line ( const char *format, const char *string, int se
     fputc ( '\n', stdout );
     fflush ( stdout );
 }
+
+
+static gboolean helper_eval_cb2 ( const GMatchInfo *info, GString *res, gpointer data )
+{
+    GHashTable *h = (GHashTable*)h;
+    gchar *match;
+    // Get the match
+    int num_match = g_match_info_get_match_count(info);
+    // Just {text} This is inside () 5.
+    if ( num_match == 5 ) {
+        match = g_match_info_fetch ( info, 4);
+        if ( match != NULL ) {
+            // Lookup the match, so we can replace it.
+            gchar *r = g_hash_table_lookup ( (GHashTable *) data, match );
+            if ( r != NULL ) {
+                // Append the replacement to the string.
+                g_string_append ( res, r );
+            }
+            // Free match.
+            g_free ( match );
+        }
+    }
+    // {} with [] guard around it.
+    else if ( num_match == 4 ) {
+        match = g_match_info_fetch ( info, 2);
+        if ( match != NULL ) {
+            // Lookup the match, so we can replace it.
+            gchar *r = g_hash_table_lookup ( (GHashTable *) data, match );
+            if ( r != NULL ) {
+                // Add (optional) prefix
+                gchar *prefix = g_match_info_fetch (info, 1);
+                g_string_append ( res, prefix );
+                g_free (prefix );
+                // Append the replacement to the string.
+                g_string_append ( res, r );
+                // Add (optional) postfix
+                gchar *post = g_match_info_fetch (info, 3);
+                g_string_append ( res, post );
+                g_free (post );
+            }
+            // Free match.
+            g_free ( match );
+        }
+    }
+    // Else we have an invalid match.
+    // Continue replacement.
+    return FALSE;
+}
+
+char *helper_string_replace_if_exists ( char * string, ... )
+{
+    GError     *error = NULL;
+    GHashTable *h;
+    h = g_hash_table_new ( g_str_hash, g_str_equal );
+    // By default, we insert terminal and ssh-client
+    g_hash_table_insert ( h, "{terminal}", config.terminal_emulator );
+    g_hash_table_insert ( h, "{ssh-client}", config.ssh_client );
+    // Add list from variable arguments.
+    va_list ap;
+    va_start ( ap, string );
+    while ( 1 ) {
+        char * key = va_arg ( ap, char * );
+        if ( key == (char *) 0 ) {
+            break;
+        }
+        char *value = va_arg ( ap, char * );
+        if ( value == (char *) 0 ) {
+            break;
+        }
+        g_hash_table_insert ( h, key, value );
+    }
+    va_end ( ap );
+
+    // Replace hits within {-\w+}.
+    GRegex *reg = g_regex_new ( "\\[(.*)({[-\\w]+})(.*)\\]|({[\\w-]+})", 0, 0, NULL );
+    char   *res = g_regex_replace_eval ( reg, string, -1, 0, 0, helper_eval_cb2, h, NULL );
+    // Free regex.
+    g_regex_unref ( reg );
+    // Destroy key-value storage.
+    g_hash_table_destroy ( h );
+    // Throw error if shell parsing fails.
+    if ( error ) {
+        char *msg = g_strdup_printf ( "Failed to parse: '%s'\nError: '%s'", string, error->message );
+        rofi_view_error_dialog ( msg, FALSE );
+        g_free ( msg );
+        // print error.
+        g_error_free ( error );
+        g_free ( res );
+        return NULL;
+    }
+    return res;
+}

test/helper-test.c

@@ -156,4 +156,30 @@ int main ( int argc, char ** argv )
         TASSERTL ( rofi_scorer_fuzzy_evaluate ("aap noot mies", 12,"Anm", 3 ), 1073741824);
 
     }
+
+
+    char *a;
+    a = helper_string_replace_if_exists ( "{terminal} [-t {title} blub ]-e {cmd}", "{cmd}", "aap", "{title}", "some title", NULL);
+    printf("%s\n",a);
+    TASSERT ( g_utf8_collate ( a, "rofi-sensible-terminal -t some title blub -e aap") == 0);
+    g_free(a);
+    a = helper_string_replace_if_exists ( "{terminal} [-t {title} blub ]-e {cmd}", "{cmd}", "aap",  NULL);
+    printf("%s\n",a);
+    TASSERT ( g_utf8_collate ( a, "rofi-sensible-terminal -e aap") == 0);
+    g_free(a);
+    a = helper_string_replace_if_exists ( "{name} [<span weight='light' size='small'><i>({category})</i></span>]", "{name}", "Librecad", "{category}", "Desktop app", NULL );
+    printf("%s\n",a);
+    TASSERT ( g_utf8_collate ( a, "Librecad <span weight='light' size='small'><i>(Desktop app)</i></span>") == 0);
+    g_free(a);
+    a = helper_string_replace_if_exists ( "{name}[ <span weight='light' size='small'><i>({category})</i></span>]", "{name}", "Librecad", NULL );
+    TASSERT ( g_utf8_collate ( a, "Librecad") == 0);
+    g_free(a);
+    a = helper_string_replace_if_exists ( "{terminal} [{title} blub ]-e {cmd}", "{cmd}", "aap", "{title}", "some title", NULL);
+    printf("%s\n",a);
+    TASSERT ( g_utf8_collate ( a, "rofi-sensible-terminal some title blub -e aap") == 0);
+    g_free(a);
+    a = helper_string_replace_if_exists ( "{terminal} [{title} blub ]-e {cmd}", "{cmd}", "aap", "{title}", NULL, NULL);
+    printf("%s\n",a);
+    TASSERT ( g_utf8_collate ( a, "rofi-sensible-terminal -e aap") == 0);
+    g_free(a);
 }