parsers: extend options parser, support optional ID in key-value lists

[sigrok-cli.git] / parsers.c

diff --git a/parsers.c b/parsers.c
index 5652b78dc096eaf3ef95d43e63e61a6f656eb891..4f3b0c5203752a4bf404b260641fca8e6436a53e 100644 (file)
--- a/parsers.c
+++ b/parsers.c
@@ -267,11 +267,44 @@ int parse_triggerstring(const struct sr_dev_inst *sdi, const char *s,
        return !error;
 }
 
-GHashTable *parse_generic_arg(const char *arg, gboolean sep_first)
+/**
+ * Create hash table from colon separated key-value pairs input text.
+ *
+ * Accepts input text as it was specified by users. Splits the colon
+ * separated key-value pairs and creates a hash table from these items.
+ * Optionally supports special forms which are useful for different CLI
+ * features.
+ *
+ * Typical form: <key>=<val>[:<key>=<val>]*
+ * Generic list of key-value pairs, all items being equal. Mere set.
+ *
+ * ID form: <id>[:<key>=<val>]*
+ * First item is not a key-value pair, instead it's an identifier. Used
+ * to specify a protocol decoder, or a device driver, or an input/output
+ * file format, optionally followed by more parameters' values. The ID
+ * part of the input spec is not optional.
+ *
+ * Optional ID: [<sel>=<id>][:<key>=<val>]*
+ * All items are key-value pairs. The first item _may_ be an identifier,
+ * if its key matches a caller specified key name. Otherwise the input
+ * text is the above typical form, a mere list of key-value pairs while
+ * none of them is special.
+ *
+ * @param[in] arg Input text.
+ * @param[in] sep_first Boolean, whether ID form is required.
+ * @param[in] key_first Keyword name if optional ID is applicable.
+ *
+ * @returns A hash table which contains the key/value pairs, or #NULL
+ *   when the input is invalid.
+ */
+GHashTable *parse_generic_arg(const char *arg,
+       gboolean sep_first, const char *key_first)
 {
        GHashTable *hash;
        int i;
        char **elements, *e;
+       int l;
+       const char *s;
 
        if (!arg || !arg[0])
                return NULL;
@@ -280,9 +313,29 @@ GHashTable *parse_generic_arg(const char *arg, gboolean sep_first)
        hash = g_hash_table_new_full(g_str_hash, g_str_equal,
                        g_free, g_free);
        elements = g_strsplit(arg, ":", 0);
-       if (sep_first)
+       if (sep_first) {
+               /*
+                * Caller requested "<id>[:<key>=<val>]*" case, Consume the
+                * first item, before processing more key-value pairs below.
+                */
                g_hash_table_insert(hash, g_strdup("sigrok_key"),
                                g_strdup(elements[i++]));
+       } else if (key_first && *key_first) {
+               /*
+                * Caller requested "[<sig>=<id>][:<key>=<val>]*" case.
+                * Optional special handling of the first item, but only
+                * consume this first item here when its keyword matched
+                * the caller's specification.
+                */
+               l = strlen(key_first);
+               s = elements[i];
+               e = strchr(s, '=');
+               if (e && e - s == l && g_str_has_prefix(s, key_first)) {
+                       g_hash_table_insert(hash,
+                               g_strdup("sigrok_key"), g_strdup(++e));
+                       i++;
+               }
+       }
        for (; elements[i]; i++) {
                e = strchr(elements[i], '=');
                if (!e)
@@ -463,7 +516,7 @@ int parse_driver(char *arg, struct sr_dev_driver **driver, GSList **drvopts)
        if (!arg)
                return FALSE;
 
-       drvargs = parse_generic_arg(arg, TRUE);
+       drvargs = parse_generic_arg(arg, TRUE, NULL);
 
        drvname = g_strdup(g_hash_table_lookup(drvargs, "sigrok_key"));
        g_hash_table_remove(drvargs, "sigrok_key");