[PATCH 1/2] json_writer: new routines to create data in JSON format
From: Jeff Hostetler <jeffhost@microsoft.com>
Add basic routines to generate data in JSON format.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
---
Makefile | 1 +
json-writer.c | 224 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
json-writer.h | 120 +++++++++++++++++++++++++++++++
3 files changed, 345 insertions(+)
create mode 100644 json-writer.c
create mode 100644 json-writer.h
diff --git a/Makefile b/Makefile
index 1a9b23b..9000369 100644
--- a/Makefile
+++ b/Makefile
@@ -815,6 +815,7 @@ LIB_OBJS += hashmap.o
LIB_OBJS += help.o
LIB_OBJS += hex.o
LIB_OBJS += ident.o
+LIB_OBJS += json-writer.o
LIB_OBJS += kwset.o
LIB_OBJS += levenshtein.o
LIB_OBJS += line-log.o
diff --git a/json-writer.c b/json-writer.c
new file mode 100644
index 0000000..755ff80
--- /dev/null
+++ b/json-writer.c
@@ -0,0 +1,224 @@
+#include "cache.h"
+#include "json-writer.h"
+
+/*
+ * Append JSON-quoted version of the given string to 'out'.
+ */
+static void jw_append_quoted_string(struct strbuf *out, const char *in)
+{
+ strbuf_addch(out, '"');
+ for (/**/; *in; in++) {
+ unsigned char c = (unsigned char)*in;
+ if (c == '"')
+ strbuf_add(out, "\\\"", 2);
+ else if (c == '\\')
+ strbuf_add(out, "\\\\", 2);
+ else if (c == '\n')
+ strbuf_add(out, "\\n", 2);
+ else if (c == '\r')
+ strbuf_add(out, "\\r", 2);
+ else if (c == '\t')
+ strbuf_add(out, "\\t", 2);
+ else if (c == '\f')
+ strbuf_add(out, "\\f", 2);
+ else if (c == '\b')
+ strbuf_add(out, "\\b", 2);
+ else if (c < 0x20)
+ strbuf_addf(out, "\\u%04x", c);
+ else
+ strbuf_addch(out, c);
+ }
+ strbuf_addch(out, '"');
+}
+
+void jw_object_begin(struct strbuf *out)
+{
+ strbuf_reset(out);
+ strbuf_addch(out, '{');
+}
+
+void jw_object_append_string(struct strbuf *out, const char *key,
+ const char *value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addch(out, ':');
+ jw_append_quoted_string(out, value);
+}
+
+void jw_object_append_int(struct strbuf *out, const char *key, int value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addf(out, ":%d", value);
+}
+
+void jw_object_append_uint64(struct strbuf *out, const char *key, uint64_t value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addf(out, ":%"PRIuMAX, value);
+}
+
+void jw_object_append_double(struct strbuf *out, const char *key, double value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addf(out, ":%f", value);
+}
+
+void jw_object_append_true(struct strbuf *out, const char *key)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addstr(out, ":true");
+}
+
+void jw_object_append_false(struct strbuf *out, const char *key)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addstr(out, ":false");
+}
+
+void jw_object_append_null(struct strbuf *out, const char *key)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addstr(out, ":null");
+}
+
+void jw_object_append_object(struct strbuf *out, const char *key,
+ const char *value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addch(out, ':');
+ strbuf_addstr(out, value);
+}
+
+void jw_object_append_array(struct strbuf *out, const char *key,
+ const char *value)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+
+ jw_append_quoted_string(out, key);
+ strbuf_addch(out, ':');
+ strbuf_addstr(out, value);
+}
+
+void jw_object_end(struct strbuf *out)
+{
+ strbuf_addch(out, '}');
+}
+
+void jw_array_begin(struct strbuf *out)
+{
+ strbuf_reset(out);
+ strbuf_addch(out, '[');
+}
+
+void jw_array_append_string(struct strbuf *out, const char *elem)
+{
+ struct strbuf qe = STRBUF_INIT;
+
+ jw_append_quoted_string(&qe, elem);
+
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, qe.buf);
+
+ strbuf_release(&qe);
+}
+
+void jw_array_append_int(struct strbuf *out, int elem)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addf(out, "%d", elem);
+}
+
+void jw_array_append_uint64(struct strbuf *out, uint64_t elem)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addf(out, "%"PRIuMAX, elem);
+}
+
+void jw_array_append_double(struct strbuf *out, double elem)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addf(out, "%f", elem);
+}
+
+void jw_array_append_true(struct strbuf *out)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, "true");
+}
+
+void jw_array_append_false(struct strbuf *out)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, "false");
+}
+
+void jw_array_append_null(struct strbuf *out)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, "null");
+}
+
+void jw_array_append_object(struct strbuf *out, const char *obj)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, obj);
+}
+
+void jw_array_append_array(struct strbuf *out, const char *array)
+{
+ if (out->len > 1)
+ strbuf_addch(out, ',');
+ strbuf_addstr(out, array);
+}
+
+void jw_array_append_argc_argv(struct strbuf *out, int argc, const char **argv)
+{
+ int k;
+
+ for (k = 0; k < argc; k++)
+ jw_array_append_string(out, argv[k]);
+}
+
+void jw_array_append_argv(struct strbuf *out, const char **argv)
+{
+ while (*argv)
+ jw_array_append_string(out, *argv++);
+}
+
+void jw_array_end(struct strbuf *out)
+{
+ strbuf_addch(out, ']');
+}
diff --git a/json-writer.h b/json-writer.h
new file mode 100644
index 0000000..0a60ab3
--- /dev/null
+++ b/json-writer.h
@@ -0,0 +1,120 @@
+#ifndef JSON_WRITER_H
+#define JSON_WRITER_H
+
+/*
+ * JSON data structures are defined at:
+ * http://json.org/
+ * http://www.ietf.org/rfc/rfc7159.txt
+ *
+ * The JSON-writer API allows one to build JSON data structures using a
+ * "struct strbuf" buffer. This is intended as a simple API to build
+ * output strings; it is not intended to be a general object model for
+ * JSON data.
+ *
+ * All string values (both keys and string r-values) are properly quoted
+ * and escaped if they contain special characters.
+ *
+ * These routines create compact JSON data (with no unnecessary whitespace,
+ * newlines, or indenting).
+ *
+ * Both "JSON objects" (aka sets of k/v pairs) and "JSON array" can be
+ * constructed using a 'begin append* end' model.
+ *
+ * Example JSON Object Usage:
+ *
+ * struct strbuf obj1 = STRBUF_INIT;
+ *
+ * jw_object_begin(&obj1);
+ * jw_object_append_string(&obj1, "a", "abc");
+ * jw_object_append_int(&obj1, "b", 42);
+ * jw_object_append_true(&obj1, "c");
+ * jw_object_end(&obj1);
+ *
+ * printf("%s\n", obj1.buf);
+ *
+ * Should yield:
+ *
+ * {"a":"abc","b":42,"c":true}
+ *
+ * Example JSON Array Usage:
+ *
+ * struct strbuf arr1 = STRBUF_INIT;
+ *
+ * jw_array_begin(&arr1);
+ * jw_array_append_string(&arr1, "abc");
+ * jw_array_append_int(&arr1, 42);
+ * jw_array_append_true(&arr1);
+ * jw_array_end(&arr1);
+ *
+ * printf("%s\n", arr1.buf);
+ *
+ * Should yield:
+ *
+ * ["abc",42,true]
+ *
+ * Nested JSON structures are also supported. These should be composed bottom
+ * up using multiple strbuf variables.
+ *
+ * Example Nested Usage (using the above "obj1" and "arr1" variables):
+ *
+ * struct strbuf obj2 = STRBUF_INIT;
+ *
+ * jw_object_begin(&obj2);
+ * jw_object_append_object(&obj2, "obj1", obj1.buf);
+ * jw_object_append_array(&obj2, "arr1", arr1.buf);
+ * jw_object_end(&obj2);
+ *
+ * printf("%s\n", obj2.buf);
+ *
+ * Should yield:
+ *
+ * {"obj1":{"a":"abc","b":42,"c":true},"arr1":["abc",42,true]}
+ *
+ * And:
+ *
+ * struct strbuf arr2 = STRBUF_INIT;
+ *
+ * jw_array_begin(&arr2);
+ * jw_array_append_object(&arr2, obj1.buf);
+ * jw_array_append_array(&arr2, arr1.buf);
+ * jw_array_end(&arr2);
+ *
+ * printf("%s\n", arr2.buf);
+ *
+ * Should yield:
+ *
+ * [{"a":"abc","b":42,"c":true},["abc",42,true]]
+ *
+ */
+
+void jw_object_begin(struct strbuf *out);
+void jw_object_append_string(struct strbuf *out, const char *key,
+ const char *value);
+void jw_object_append_int(struct strbuf *out, const char *key, int value);
+void jw_object_append_uint64(struct strbuf *out, const char *key,
+ uint64_t value);
+void jw_object_append_double(struct strbuf *out, const char *key, double value);
+void jw_object_append_true(struct strbuf *out, const char *key);
+void jw_object_append_false(struct strbuf *out, const char *key);
+void jw_object_append_null(struct strbuf *out, const char *key);
+void jw_object_append_object(struct strbuf *out, const char *key,
+ const char *value);
+void jw_object_append_array(struct strbuf *out, const char *key,
+ const char *value);
+void jw_object_end(struct strbuf *out);
+
+void jw_array_begin(struct strbuf *out);
+void jw_array_append_string(struct strbuf *out, const char *elem);
+void jw_array_append_int(struct strbuf *out, int elem);
+void jw_array_append_uint64(struct strbuf *out, uint64_t elem);
+void jw_array_append_double(struct strbuf *out, double elem);
+void jw_array_append_true(struct strbuf *out);
+void jw_array_append_false(struct strbuf *out);
+void jw_array_append_null(struct strbuf *out);
+void jw_array_append_object(struct strbuf *out, const char *obj);
+void jw_array_append_array(struct strbuf *out, const char *array);
+void jw_array_append_argc_argv(struct strbuf *out, int argc, const char **argv);
+void jw_array_append_argv(struct strbuf *out, const char **argv);
+void jw_array_end(struct strbuf *out);
+
+#endif /* JSON_WRITER_H */
--
2.9.3