cli: changing nmcli output to better fit both computer and human needs

The output is basically tabular with fields (columns) presenting specific pieces of info.
Each line represents a single object. It's possible to switch to multiline output using
'--multiline' option. In that mode single object is presented on more lines - each field
on its line.
Terse mode now uses ':' as field separator. It also escapes all occurences of ':' and '\'
inside field values to ease parsing. The escaping behaviour can be controlled through
'--escape' option. By default, escaping is switched on in tabular mode. When using terse
mode ('--terse'), '--fields' option is mandatory for specifying required fields. That helps
for flexibility and backwards compatibility.
Not all output is converted yet.

cli/src/utils.c

@@ -21,6 +21,7 @@
 #include <string.h>
 
 #include <glib.h>
+#include <glib/gi18n.h>
 
 #include "utils.h"
 
@@ -46,6 +47,171 @@ next_arg (int *argc, char ***argv)
 	return 0;
 }
 
+/*
+ * Parse comma separated fields in 'fields_str' according to 'fields_array'.
+ * IN:  'field_str':    comma-separated fields names
+ *      'fields_array': array of allowed fields
+ * RETURN: GArray with indices representing fields in 'fields_array'.
+ */
+GArray *
+parse_output_fields (const char *fields_str, const NmcOutputField fields_array[], GError **error)
+{
+	char **fields, **iter;
+	GArray *array;
+	int i;
+
+	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+
+	array = g_array_new (FALSE, FALSE, sizeof (int));
+
+	/* Split supplied fields string */
+	fields = g_strsplit_set (fields_str, ",", -1);
+	for (iter = fields; iter && *iter; iter++) {
+		for (i = 0; fields_array[i].name; i++) {
+			if (strcasecmp (*iter, fields_array[i].name) == 0) {
+				g_array_append_val (array, i);
+				break;
+			}
+		}
+		if (fields_array[i].name == NULL) {
+			if (!strcasecmp (*iter, "all") || !strcasecmp (*iter, "common"))
+				g_set_error (error, 0, 0, _("Error: 'con status': field '%s' has to be alone."), *iter);
+
+			else
+				g_set_error (error, 0, 0, _("Error: 'con status': invalid field '%s'."), *iter);
+			g_array_free (array, TRUE);
+			array = NULL;
+			goto done;
+		}
+	}
+done:
+	return array;
+}
+
+void
+print_fields (const NmcPrintFields fields, const NmcOutputField field_values[])
+{
+	GString *str;
+	int width1, width2;
+	int table_width = 0;
+	char *line = NULL;
+	char *indent_str;
+	const char *value;
+	int i, idx;
+	gboolean multiline = fields.flags & NMC_PF_FLAG_MULTILINE;
+	gboolean terse = fields.flags & NMC_PF_FLAG_TERSE;
+	gboolean pretty = fields.flags & NMC_PF_FLAG_PRETTY;
+	gboolean header = fields.flags & NMC_PF_FLAG_HEADER;
+	gboolean escape = fields.flags & NMC_PF_FLAG_ESCAPE;
+
+	/* Headers are not printed in terse mode */
+	if (header && terse)
+		return;
+
+	if (multiline) {
+	/* --- Multiline mode --- */
+		if (header && pretty) {
+			/* Print the table header */
+			table_width = g_utf8_strlen (fields.header_name, -1) + 4;
+			line = g_strnfill (79, '=');
+			width1 = strlen (fields.header_name);
+			width2 = g_utf8_strlen (fields.header_name, -1);
+			printf ("%s\n", line);
+			printf ("%*s\n", (table_width + width2)/2 + width1 - width2, fields.header_name);
+			printf ("%s\n", line);
+			g_free (line);
+		}
+
+		/* Print values */
+		if (!header) {
+			for (i = 0; i < fields.indices->len; i++) {
+				char *tmp;
+				idx = g_array_index (fields.indices, int, i);
+				tmp = g_strdup_printf ("%s:", _(field_values[idx].name_l10n));
+				printf ("%-*s%s\n", terse ? 0 : 20, tmp, field_values[idx].value);
+				g_free (tmp);
+			}
+			if (pretty) {
+				line = g_strnfill (79, '-');
+				printf ("%s\n", line);
+				g_free (line);
+			}
+		}
+		return;
+	}
+
+	/* --- Tabular mode: each line = one object --- */
+	str = g_string_new (NULL);
+
+	for (i = 0; i < fields.indices->len; i++) {
+		idx = g_array_index (fields.indices, int, i);
+		if (header)
+			value = _(field_values[idx].name_l10n);
+		else
+			value = field_values[idx].value;
+		if (terse) {
+			if (escape) {
+				const char *p = value;
+				while (*p) {
+					if (*p == ':' || *p == '\\')
+						g_string_append_c (str, '\\');  /* Escaping by '\' */
+					g_string_append_c (str, *p);
+					p++;
+				}
+			}
+			else 
+				g_string_append_printf (str, "%s", value);
+			g_string_append_c (str, ':');  /* Column separator */
+		} else {
+			width1 = strlen (value);
+			width2 = g_utf8_strlen (value, -1);  /* Width of the string (in screen colums) */
+			if (strlen (value) == 0)
+				value = "--";
+			g_string_append_printf (str, "%-*s", field_values[idx].width + width1 - width2, value);
+			g_string_append_c (str, ' ');  /* Column separator */
+			table_width += field_values[idx].width + width1 - width2 + 1;
+		}
+	}
+
+	if (table_width <= 0)
+		table_width = g_utf8_strlen (fields.header_name, -1) + 4;
+
+	if (header && pretty) {
+		/* Print the table header */
+		line = g_strnfill (table_width, '=');
+		width1 = strlen (fields.header_name);
+		width2 = g_utf8_strlen (fields.header_name, -1);
+		printf ("%s\n", line);
+		printf ("%*s\n", (table_width + width2)/2 + width1 - width2, fields.header_name);
+		printf ("%s\n", line);
+		g_free (line);
+	}
+
+
+	/* Print the line */
+	if (str->len > 0) {
+		g_string_truncate (str, str->len-1);  /* Chop off last column separator */
+		if (fields.indent > 0) {
+			indent_str = g_strnfill (fields.indent, ' ');
+			g_string_prepend (str,  indent_str);
+			g_free (indent_str);
+		}
+		printf ("%s\n", str->str);
+	}
+
+	if (header && pretty) {
+		if (str->len > 0) {
+			line = g_strnfill (table_width, '-');
+			printf ("%s\n", line);
+			g_free (line);
+		}
+	}
+
+	g_string_free (str, TRUE);
+}
+
+
+/*--- obsolete printing functions ---*/
 void
 print_table_header (const char *name, ...)
 {