Add structured output formatter for JSON and plain text (but don't use them yet).

Using the new structured printer support in sprinter.h, implement
sprinter_json_create, which returns a new JSON structured output
formatter. The formatter prints output similar to the existing JSON, but
with differences in whitespace (mostly newlines, --output=summary prints
the entire message summary on one line, not split across multiple lines).

Also implement a "structured" formatter for plain text that prints
prefixed strings, to be used with notmuch-search.c plain text output.

1 files changed, 126 insertions, 0 deletions

diff --git a/sprinter-text.c b/sprinter-text.c
new file mode 100644
index 00000000..b208840b
--- /dev/null
+++ b/sprinter-text.c
@@ -0,0 +1,126 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <talloc.h>
+#include "sprinter.h"
+
+/* "Structured printer" interface for unstructured text printing.
+ * Note that --output=summary is dispatched and formatted in
+ * notmuch-search.c, the code in this file is only used for all other
+ * output types.
+ */
+
+struct sprinter_text {
+    struct sprinter vtable;
+    FILE *stream;
+
+    /* The current prefix to be printed with string/integer/boolean
+     * data.
+     */
+    const char *current_prefix;
+
+    /* A flag to indicate if this is the first tag. Used in list of tags
+     * for summary.
+     */
+    notmuch_bool_t first_tag;
+};
+
+static void
+text_string (struct sprinter *sp, const char *val)
+{
+    struct sprinter_text *sptxt = (struct sprinter_text *) sp;
+
+    if (sptxt->current_prefix != NULL)
+	fprintf (sptxt->stream, "%s:", sptxt->current_prefix);
+
+    fputs(val, sptxt->stream);
+}
+
+static void
+text_integer (struct sprinter *sp, int val)
+{
+    struct sprinter_text *sptxt = (struct sprinter_text *) sp;
+
+    fprintf (sptxt->stream, "%d", val);
+}
+
+static void
+text_boolean (struct sprinter *sp, notmuch_bool_t val)
+{
+    struct sprinter_text *sptxt = (struct sprinter_text *) sp;
+
+    fputs (val ? "true" : "false", sptxt->stream);
+}
+
+static void
+text_separator (struct sprinter *sp)
+{
+    struct sprinter_text *sptxt = (struct sprinter_text *) sp;
+
+    fputc ('\n', sptxt->stream);
+}
+
+static void
+text_set_prefix (struct sprinter *sp, const char *prefix)
+{
+    struct sprinter_text *sptxt = (struct sprinter_text *) sp;
+
+    sptxt->current_prefix = prefix;
+}
+
+/* The structure functions begin_map, begin_list, end and map_key
+ * don't do anything in the text formatter.
+ */
+
+static void
+text_begin_map (unused (struct sprinter *sp))
+{
+}
+
+static void
+text_begin_list (unused (struct sprinter *sp))
+{
+}
+
+static void
+text_end (unused (struct sprinter *sp))
+{
+}
+
+static void
+text_null (unused (struct sprinter *sp))
+{
+}
+
+static void
+text_map_key (unused (struct sprinter *sp), unused (const char *key))
+{
+}
+
+struct sprinter *
+sprinter_text_create (const void *ctx, FILE *stream)
+{
+    static const struct sprinter_text template = {
+	.vtable = {
+	    .begin_map = text_begin_map,
+	    .begin_list = text_begin_list,
+	    .end = text_end,
+	    .string = text_string,
+	    .integer = text_integer,
+	    .boolean = text_boolean,
+	    .null = text_null,
+	    .map_key = text_map_key,
+	    .separator = text_separator,
+	    .set_prefix = text_set_prefix,
+	    .is_text_printer = TRUE,
+	},
+    };
+    struct sprinter_text *res;
+
+    res = talloc (ctx, struct sprinter_text);
+    if (! res)
+	return NULL;
+
+    *res = template;
+    res->stream = stream;
+    return &res->vtable;
+}