[EXPERIMENTAL PATCH] S-expression structured output backend

[EXPERIMENTAL PATCH] S-expression structured output backend

[Ilari Liusvaara]

Add structured output mode 'sexp' that prints out canonical form
S-expressions.

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
---
 Makefile      |    1 +
 output-sexp.c |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 output.c      |    9 ++++++-
 output.h      |    3 +-
 4 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 output-sexp.c

diff --git a/Makefile b/Makefile
index d32a334..8b0fc21 100644
--- a/Makefile
+++ b/Makefile
@@ -582,6 +582,7 @@ LIB_OBJS += notes-cache.o
 LIB_OBJS += object.o
 LIB_OBJS += output.o
 LIB_OBJS += output-json.o
+LIB_OBJS += output-sexp.o
 LIB_OBJS += output-normal.o
 LIB_OBJS += output-xml.o
 LIB_OBJS += output-zero.o
diff --git a/output-sexp.c b/output-sexp.c
new file mode 100644
index 0000000..df8d56b
--- /dev/null
+++ b/output-sexp.c
@@ -0,0 +1,76 @@
+#include "git-compat-util.h"
+#include "output.h"
+
+static void sexp_str(FILE *file, const char *value)
+{
+	fprintf(file, "%llu:%s", (uint64_t)strlen(value), value);
+}
+
+static void sexp_container_start(FILE *file, const char *name)
+{
+	fprintf(file, "(");
+}
+
+static void sexp_container_end(FILE *file, const char *name)
+{
+	fprintf(file, ")");
+}
+
+static void sexp_objitem_end(FILE *file, const char *name, int first)
+{
+	fprintf(file, ")");
+}
+
+static void sexp_obj_item_start(FILE *file, const char *name, int first)
+{
+	fprintf(file, "(");
+	sexp_str(file,name);
+}
+
+static void sexp_bool(FILE *file, int value)
+{
+	if (value)
+		sexp_str(file, "true");
+	else
+		sexp_str(file, "false");
+}
+
+static void sexp_int_(FILE *file, int64_t value)
+{
+	char buffer[256];
+	sprintf(buffer, "%lli", value);
+	sexp_str(file, buffer);
+}
+
+static void sexp_uint(FILE *file, uint64_t value)
+{
+	char buffer[256];
+	sprintf(buffer, "%llu", value);
+	sexp_str(file, buffer);
+}
+
+static void sexp_double_(FILE *file, double value, int precision)
+{
+	char buffer[256];
+	sprintf(buffer, "%.*f", precision, value);
+	sexp_str(file, buffer);
+}
+
+
+struct output_ops output_sexp_ops = {
+	sexp_container_start,
+	sexp_container_end,
+	sexp_obj_item_start,
+	sexp_objitem_end,
+
+	sexp_container_start,
+	sexp_container_end,
+	NULL,
+	NULL,
+
+	sexp_bool,
+	sexp_str,
+	sexp_int_,
+	sexp_uint,
+	sexp_double_,
+};
diff --git a/output.c b/output.c
index 3be1560..9d04cc4 100644
--- a/output.c
+++ b/output.c
@@ -8,12 +8,14 @@ extern struct output_ops output_normal_ops;
 extern struct output_ops output_zero_ops;
 extern struct output_ops output_json_ops;
 extern struct output_ops output_xml_ops;
+extern struct output_ops output_sexp_ops;
 
 struct output_ops *output_ops[] = {
 	&output_normal_ops,
 	&output_zero_ops,
 	&output_json_ops,
 	&output_xml_ops,
+	&output_sexp_ops,
 };
 
 enum output_style handle_output_arg(char *s)
@@ -28,6 +30,8 @@ enum output_style handle_output_arg(char *s)
 		return OUTPUT_JSON;
 	else if (!strcmp(s, "xml"))
 		return OUTPUT_XML;
+	else if (!strcmp(s, "sexp"))
+		return OUTPUT_SEXP;
 	else
 		die("Invalid output style '%s'", s);
 }
@@ -54,8 +58,11 @@ void output_end(struct output_context *context)
 	 * OUTPUT_NORMAL and OUTPUT_ZERO are special cases - the output format
 	 * is _already_ defined so we have to stick to the rules, we can't add
 	 * _anything_
+	 *
+	 * As for S-Expression output, no, canonical mode does not allow trailing
+	 * newline, so suppress it.
 	 */
-	if (context->style > OUTPUT_ZERO)
+	if (context->style > OUTPUT_ZERO && context->style != OUTPUT_SEXP)
 		fprintf(context->file, "\n");
 
 	free(context);
diff --git a/output.h b/output.h
index cc0b921..7ee2cd7 100644
--- a/output.h
+++ b/output.h
@@ -6,6 +6,7 @@ enum output_style {
 	OUTPUT_ZERO,
 	OUTPUT_JSON,
 	OUTPUT_XML,
+	OUTPUT_SEXP,
 };
 
 struct output_ops {
@@ -59,7 +60,7 @@ extern struct option OUTPUT_OPTION;
 
 #define OPT_OUTPUT(s, l, v) { OPTION_STRING, (s), (l), (v), "style",     \
 			      "Use a structured output style, options: " \
-			      "no, zero, json, xml (Default: zero)",     \
+			      "no, zero, json, xml, sexp (Default: zero)",     \
 			      PARSE_OPT_OPTARG, NULL, (intptr_t)"zero" }
 
 enum output_style handle_output_arg(char *s);
-- 
1.7.0.2.282.g5b1c2

Re: [EXPERIMENTAL PATCH] S-expression structured output backend

[Ping Yin]

On Tue, Apr 13, 2010 at 6:23 PM, Ilari Liusvaara
<ilari.liusvaara@elisanet.fi> wrote:
> Add structured output mode 'sexp' that prints out canonical form
> S-expressions.
>
> Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
> ---
>  Makefile      |    1 +
>  output-sexp.c |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I think it's better to put all output-* files in a separate directory.