[PATCH v7 2/3] Add structured output formatter for JSON and plain text (but don't use them yet).
Austin Clements
amdragon at MIT.EDU
Sun Jul 22 09:08:43 PDT 2012
Quoth craven at gmx.net on Jul 20 at 8:36 am:
> From: <craven at gmx.net>
>
> 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.
> ---
> Makefile.local | 2 +
> sprinter-json.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> sprinter-text.c | 126 ++++++++++++++++++++++++++++++++++++++
> sprinter.h | 10 +++
> 4 files changed, 323 insertions(+)
> create mode 100644 sprinter-json.c
> create mode 100644 sprinter-text.c
>
> diff --git a/Makefile.local b/Makefile.local
> index a890df2..296995d 100644
> --- a/Makefile.local
> +++ b/Makefile.local
> @@ -290,6 +290,8 @@ notmuch_client_srcs = \
> notmuch-show.c \
> notmuch-tag.c \
> notmuch-time.c \
> + sprinter-json.c \
> + sprinter-text.c \
> query-string.c \
> mime-node.c \
> crypto.c \
> diff --git a/sprinter-json.c b/sprinter-json.c
> new file mode 100644
> index 0000000..32daa5a
> --- /dev/null
> +++ b/sprinter-json.c
> @@ -0,0 +1,185 @@
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <talloc.h>
> +#include "sprinter.h"
> +
> +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;
> +
> + /* A flag to signify that a separator should be inserted in the
> + * output as soon as possible.
> + */
> + notmuch_bool_t insert_separator;
> +};
> +
> +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) {
> + fputc (',', spj->stream);
> + if (spj->insert_separator) {
> + fputc ('\n', spj->stream);
> + spj->insert_separator = FALSE;
> + } else
> + fputc (' ', spj->stream);
> + } else
> + spj->state->first = FALSE;
Just a nit: if you roll a v8, it would be nice to have braces around
both of these else parts to match the braces on the then parts.
Obviously this doesn't warrant a v8 on its own, though.
> + }
> + 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_set_prefix (unused (struct sprinter *sp), unused (const char *name))
> +{
> +}
> +
> +static void
> +json_separator (struct sprinter *sp)
> +{
> + struct sprinter_json *spj = (struct sprinter_json *) sp;
> +
> + spj->insert_separator = TRUE;
> +}
> +
> +struct sprinter *
> +sprinter_json_create (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,
> + .separator = json_separator,
> + .set_prefix = json_set_prefix,
> + .is_text_printer = FALSE,
> + }
> + };
> + struct sprinter_json *res;
> +
> + res = talloc (ctx, struct sprinter_json);
> + if (! res)
> + return NULL;
> +
> + *res = template;
> + res->stream = stream;
> + return &res->vtable;
> +}
> diff --git a/sprinter-text.c b/sprinter-text.c
> new file mode 100644
> index 0000000..b208840
> --- /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;
> +}
> diff --git a/sprinter.h b/sprinter.h
> index 77dc26f..6680d41 100644
> --- a/sprinter.h
> +++ b/sprinter.h
> @@ -55,4 +55,14 @@ typedef struct sprinter {
> notmuch_bool_t is_text_printer;
> } sprinter_t;
>
> +
> +/* Create a new unstructured printer that emits the default text format
> + * for "notmuch search". */
> +struct sprinter *
> +sprinter_text_create (const void *ctx, FILE *stream);
> +
> +/* Create a new structure printer that emits JSON. */
> +struct sprinter *
> +sprinter_json_create (const void *ctx, FILE *stream);
> +
> #endif // NOTMUCH_SPRINTER_H
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