[PATCH v4 2/3] Add structured output formatter for JSON.
Tomi Ollila
tomi.ollila at iki.fi
Thu Jul 12 03:10:27 PDT 2012
On Thu, Jul 12 2012, craven at gmx.net wrote:
> Using the new structured printer support in sprinter.h, implement
> sprinter_json_new, which returns a new JSON structured output
> formatter.
>
> The formatter prints output similar to the existing JSON, but with
> differences in whitespace (mostly newlines).
> ---
> Makefile.local | 1 +
> sprinter.c | 172 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 173 insertions(+)
> create mode 100644 sprinter.c
>
> diff --git a/Makefile.local b/Makefile.local
> index a890df2..8baf0c2 100644
> --- a/Makefile.local
> +++ b/Makefile.local
> @@ -290,6 +290,7 @@ notmuch_client_srcs = \
> notmuch-show.c \
> notmuch-tag.c \
> notmuch-time.c \
> + sprinter.c \
> query-string.c \
> mime-node.c \
> crypto.c \
> diff --git a/sprinter.c b/sprinter.c
> new file mode 100644
> index 0000000..649f79a
> --- /dev/null
> +++ b/sprinter.c
> @@ -0,0 +1,172 @@
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <talloc.h>
> +#include "sprinter.h"
> +
> +#define ARRAY_SIZE(arr) (sizeof (arr) / sizeof (arr[0]))
You're including sprinter.h which includes notmuch-client.h which
defines ARRAY_SIZE (Interesting that you did not get error(/warning?)
about this)
Rest looks good -- except the whitespace -- as I looked through Austin's
code yesterday you're just replicated the same lines :D. Easiest
to fix is probably just running
uncrustify -c devel/uncrustify.cfg --replace sprinter.c
Tomi
> +
> +struct sprinter *
> +sprinter_text = NULL;
> +
> +/*
> + * Every below here is the implementation of the JSON printer.
> + */
> +
> +struct sprinter_json
> +{
> + struct sprinter vtable;
> + FILE *stream;
> + /* Top of the state stack, or NULL if the printer is not currently
> + * inside any aggregate types. */
> + struct json_state *state;
> +};
> +
> +struct json_state
> +{
> + struct json_state *parent;
> + /* True if nothing has been printed in this aggregate yet.
> + * Suppresses the comma before a value. */
> + notmuch_bool_t first;
> + /* The character that closes the current aggregate. */
> + char close;
> +};
> +
> +/* Helper function to set up the stream to print a value. If this
> + * value follows another value, prints a comma. */
> +static struct sprinter_json *
> +json_begin_value(struct sprinter *sp)
> +{
> + struct sprinter_json *spj = (struct sprinter_json*)sp;
> + if (spj->state) {
> + if (!spj->state->first)
> + fputs (", ", spj->stream);
> + else
> + spj->state->first = false;
> + }
> + return spj;
> +}
> +
> +/* Helper function to begin an aggregate type. Prints the open
> + * character and pushes a new state frame. */
> +static void
> +json_begin_aggregate(struct sprinter *sp, char open, char close)
> +{
> + struct sprinter_json *spj = json_begin_value (sp);
> + struct json_state *state = talloc (spj, struct json_state);
> +
> + fputc (open, spj->stream);
> + state->parent = spj->state;
> + state->first = true;
> + state->close = close;
> + spj->state = state;
> +}
> +
> +static void
> +json_begin_map(struct sprinter *sp)
> +{
> + json_begin_aggregate (sp, '{', '}');
> +}
> +
> +static void
> +json_begin_list(struct sprinter *sp)
> +{
> + json_begin_aggregate (sp, '[', ']');
> +}
> +
> +static void
> +json_end(struct sprinter *sp)
> +{
> + struct sprinter_json *spj = (struct sprinter_json*)sp;
> + struct json_state *state = spj->state;
> +
> + fputc (spj->state->close, spj->stream);
> + spj->state = state->parent;
> + talloc_free (state);
> + if(spj->state == NULL)
> + fputc ('\n', spj->stream);
> +}
> +
> +static void
> +json_string(struct sprinter *sp, const char *val)
> +{
> + static const char * const escapes[] = {
> + ['\"'] = "\\\"", ['\\'] = "\\\\", ['\b'] = "\\b",
> + ['\f'] = "\\f", ['\n'] = "\\n", ['\t'] = "\\t"
> + };
> + struct sprinter_json *spj = json_begin_value (sp);
> + fputc ('"', spj->stream);
> + for (; *val; ++val) {
> + unsigned char ch = *val;
> + if (ch < ARRAY_SIZE(escapes) && escapes[ch])
> + fputs (escapes[ch], spj->stream);
> + else if (ch >= 32)
> + fputc (ch, spj->stream);
> + else
> + fprintf (spj->stream, "\\u%04x", ch);
> + }
> + fputc ('"', spj->stream);
> +}
> +
> +static void
> +json_integer(struct sprinter *sp, int val)
> +{
> + struct sprinter_json *spj = json_begin_value (sp);
> + fprintf (spj->stream, "%d", val);
> +}
> +
> +static void
> +json_boolean(struct sprinter *sp, notmuch_bool_t val)
> +{
> + struct sprinter_json *spj = json_begin_value (sp);
> + fputs (val ? "true" : "false", spj->stream);
> +}
> +
> +static void
> +json_null(struct sprinter *sp)
> +{
> + struct sprinter_json *spj = json_begin_value (sp);
> + fputs ("null", spj->stream);
> +}
> +
> +static void
> +json_map_key(struct sprinter *sp, const char *key)
> +{
> + struct sprinter_json *spj = (struct sprinter_json*)sp;
> + json_string (sp, key);
> + fputs (": ", spj->stream);
> + spj->state->first = true;
> +}
> +
> +static void
> +json_frame(struct sprinter *sp)
> +{
> + struct sprinter_json *spj = (struct sprinter_json*)sp;
> + fputc ('\n', spj->stream);
> +}
> +
> +struct sprinter *
> +sprinter_json_new(const void *ctx, FILE *stream)
> +{
> + static const struct sprinter_json template = {
> + .vtable = {
> + .begin_map = json_begin_map,
> + .begin_list = json_begin_list,
> + .end = json_end,
> + .string = json_string,
> + .integer = json_integer,
> + .boolean = json_boolean,
> + .null = json_null,
> + .map_key = json_map_key,
> + .frame = json_frame,
> + }
> + };
> + struct sprinter_json *res;
> +
> + res = talloc (ctx, struct sprinter_json);
> + if (!res)
> + return NULL;
> +
> + *res = template;
> + res->stream = stream;
> + return &res->vtable;
> +}
> --
> 1.7.11.1
>
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