--- /dev/null
+/* MIT (BSD) license - see LICENSE file for details */
+#include <ccan/json_escape/json_escape.h>
+#include <ccan/json_out/json_out.h>
+#include <ccan/membuf/membuf.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+struct json_out {
+ /* Callback if we reallocate. */
+ void (*move_cb)(struct json_out *jout, ptrdiff_t delta, void *arg);
+ void *cb_arg;
+
+#ifdef CCAN_JSON_OUT_DEBUG
+ /* tal_arr of types ( or [ we're enclosed in. */
+ char *wrapping;
+#endif
+ /* True if we haven't yet put an element in current wrapping */
+ bool empty;
+
+ /* Output. */
+ MEMBUF(char) outbuf;
+};
+
+/* Realloc helper for tal membufs */
+static void *membuf_tal_realloc(struct membuf *mb,
+ void *rawelems, size_t newsize)
+{
+ char *p = rawelems;
+
+ tal_resize(&p, newsize);
+ return p;
+}
+
+struct json_out *json_out_new(const tal_t *ctx)
+{
+ struct json_out *jout = tal(ctx, struct json_out);
+
+ membuf_init(&jout->outbuf,
+ tal_arr(jout, char, 64), 64, membuf_tal_realloc);
+#ifdef CCAN_JSON_OUT_DEBUG
+ jout->wrapping = tal_arr(jout, char, 0);
+#endif
+ jout->empty = true;
+ jout->move_cb = NULL;
+ return jout;
+}
+
+void json_out_call_on_move_(struct json_out *jout,
+ void (*cb)(struct json_out *jout, ptrdiff_t delta,
+ void *arg),
+ void *arg)
+{
+ if (cb)
+ assert(!jout->move_cb);
+ jout->move_cb = cb;
+ jout->cb_arg = arg;
+}
+
+struct json_out *json_out_dup(const tal_t *ctx, const struct json_out *src)
+{
+ size_t num_elems = membuf_num_elems(&src->outbuf);
+ char *elems = membuf_elems(&src->outbuf);
+ struct json_out *jout = tal_dup(ctx, struct json_out, src);
+ membuf_init(&jout->outbuf,
+ tal_dup_arr(jout, char, elems, num_elems, 0),
+ num_elems, membuf_tal_realloc);
+ membuf_added(&jout->outbuf, num_elems);
+#ifdef CCAN_JSON_OUT_DEBUG
+ jout->wrapping = tal_dup_arr(jout, char,
+ jout->wrapping, tal_count(jout->wrapping),
+ 0);
+#endif
+ return jout;
+}
+
+static void indent(struct json_out *jout, char type)
+{
+#ifdef CCAN_JSON_OUT_DEBUG
+ size_t n = tal_count(jout->wrapping);
+ tal_resize(&jout->wrapping, n+1);
+ jout->wrapping[n] = type;
+#endif
+ jout->empty = true;
+}
+
+static void unindent(struct json_out *jout, char type)
+{
+#ifdef CCAN_JSON_OUT_DEBUG
+ size_t indent = tal_count(jout->wrapping);
+ assert(indent > 0);
+ /* Both [ and ] and { and } are two apart in ASCII */
+ assert(jout->wrapping[indent-1] == type - 2);
+ tal_resize(&jout->wrapping, indent-1);
+#endif
+ jout->empty = false;
+}
+
+/* Make sure jout->outbuf has room for len: return pointer */
+static char *mkroom(struct json_out *jout, size_t len)
+{
+ ptrdiff_t delta = membuf_prepare_space(&jout->outbuf, len);
+
+ if (delta && jout->move_cb)
+ jout->move_cb(jout, delta, jout->cb_arg);
+
+ return membuf_space(&jout->outbuf);
+}
+
+static void check_fieldname(const struct json_out *jout,
+ const char *fieldname)
+{
+#ifdef CCAN_JSON_OUT_DEBUG
+ size_t n = tal_count(jout->wrapping);
+ if (n == 0)
+ /* Can't have a fieldname if not in anything! */
+ assert(!fieldname);
+ else if (jout->wrapping[n-1] == '[')
+ /* No fieldnames in arrays. */
+ assert(!fieldname);
+ else {
+ /* Must have fieldnames in objects. */
+ assert(fieldname);
+ /* We don't escape this for you */
+ assert(!json_escape_needed(fieldname, strlen(fieldname)));
+ }
+#endif
+}
+
+char *json_out_member_direct(struct json_out *jout,
+ const char *fieldname, size_t extra)
+{
+ char *dest;
+
+ /* Prepend comma if required. */
+ if (!jout->empty)
+ extra++;
+
+ check_fieldname(jout, fieldname);
+ if (fieldname)
+ extra += 1 + strlen(fieldname) + 2;
+
+ if (!extra) {
+ dest = NULL;
+ goto out;
+ }
+
+ dest = mkroom(jout, extra);
+
+ if (!jout->empty)
+ *(dest++) = ',';
+ if (fieldname) {
+ *(dest++) = '"';
+ memcpy(dest, fieldname, strlen(fieldname));
+ dest += strlen(fieldname);
+ *(dest++) = '"';
+ *(dest++) = ':';
+ }
+ membuf_added(&jout->outbuf, extra);
+
+out:
+ jout->empty = false;
+ return dest;
+}
+
+void json_out_start(struct json_out *jout, const char *fieldname, char type)
+{
+ assert(type == '[' || type == '{');
+ json_out_member_direct(jout, fieldname, 1)[0] = type;
+ indent(jout, type);
+}
+
+void json_out_end(struct json_out *jout, char type)
+{
+ assert(type == '}' || type == ']');
+ json_out_direct(jout, 1)[0] = type;
+ unindent(jout, type);
+}
+
+void json_out_addv(struct json_out *jout,
+ const char *fieldname,
+ bool quote,
+ const char *fmt,
+ va_list ap)
+{
+ size_t fmtlen, avail;
+ va_list ap2;
+ char *dst;
+
+ json_out_member_direct(jout, fieldname, 0);
+
+ /* Make a copy in case we need it below. */
+ va_copy(ap2, ap);
+
+ /* We can use any additional space, but need room for ". */
+ avail = membuf_num_space(&jout->outbuf);
+ if (quote) {
+ if (avail < 2)
+ avail = 0;
+ else
+ avail -= 2;
+ }
+
+ /* Try printing in place first. */
+ dst = membuf_space(&jout->outbuf);
+ fmtlen = vsnprintf(dst + quote, avail, fmt, ap);
+
+ /* Horrible subtlety: vsnprintf *will* NUL terminate, even if it means
+ * chopping off the last character. So if fmtlen ==
+ * membuf_num_space(&jout->outbuf), the result was truncated! */
+ if (fmtlen + (int)quote*2 >= membuf_num_space(&jout->outbuf)) {
+ /* Make room for NUL terminator, even though we don't want it */
+ dst = mkroom(jout, fmtlen + 1 + (int)quote*2);
+ vsprintf(dst + quote, fmt, ap2);
+ }
+
+ /* Of course, if we need to escape it, we have to redo it all. */
+ if (json_escape_needed(dst + quote, fmtlen)) {
+ struct json_escape *e;
+ e = json_escape_len(NULL, dst + quote, fmtlen);
+ fmtlen = strlen(e->s);
+ dst = mkroom(jout, fmtlen + (int)quote*2);
+ memcpy(dst + quote, e, fmtlen);
+ tal_free(e);
+ }
+
+ if (quote) {
+ dst[0] = '"';
+ dst[fmtlen+1] = '"';
+ }
+ membuf_added(&jout->outbuf, fmtlen + (int)quote*2);
+ va_end(ap2);
+}
+
+void json_out_add(struct json_out *jout,
+ const char *fieldname,
+ bool quote,
+ const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ json_out_addv(jout, fieldname, quote, fmt, ap);
+ va_end(ap);
+}
+
+void json_out_addstr(struct json_out *jout,
+ const char *fieldname,
+ const char *str)
+{
+ size_t len = strlen(str);
+ char *p;
+
+ p = json_out_member_direct(jout, fieldname, len + 2);
+ p[0] = p[1+len] = '"';
+ memcpy(p+1, str, len);
+}
+
+void json_out_add_splice(struct json_out *jout,
+ const char *fieldname,
+ const struct json_out *src)
+{
+ const char *p;
+ size_t len;
+
+ p = json_out_contents(src, &len);
+ memcpy(json_out_member_direct(jout, fieldname, len), p, len);
+}
+
+char *json_out_direct(struct json_out *jout, size_t len)
+{
+ char *p = mkroom(jout, len);
+ membuf_added(&jout->outbuf, len);
+ return p;
+}
+
+void json_out_finished(const struct json_out *jout)
+{
+#ifdef CCAN_JSON_OUT_DEBUG
+ assert(tal_count(jout->wrapping) == 0);
+#endif
+}
+
+const char *json_out_contents(const struct json_out *jout, size_t *len)
+{
+ *len = membuf_num_elems(&jout->outbuf);
+ return *len ? membuf_elems(&jout->outbuf) : NULL;
+}
+
+void json_out_consume(struct json_out *jout, size_t len)
+{
+ membuf_consume(&jout->outbuf, len);
+}
projects / ccan / blobdiff