mongrel2 json gen speed-up.

gistfile1.c

#if 1
#define B(K, V) if((V) != NULL) { \
	vstr = json_escape(V); \
	bcatcstr(headers, ",\""); \
	bcatcstr(headers, bdata(K)); \
	bcatcstr(headers, "\":\""); \
	bcatcstr(headers, bdata(vstr)); \
	bcatcstr(headers, "\""); \
	bdestroy(vstr); \
}
#else
#define B(K, V) if((V) != NULL) { \
	vstr = json_escape(V); \
	bformata(headers, ",\"%s\":\"%s\"", bdata(K), bdata(vstr)); \
	bdestroy(vstr); \
}
#endif

static struct tagbstring QUOTE_CHAR = bsStatic("\"");
static struct tagbstring QUOTE_REPLACE = bsStatic("\\\"");

static struct tagbstring BSLASH_CHAR = bsStatic("\\");
static struct tagbstring BSLASH_REPLACE = bsStatic("\\\\");

static inline bstring json_escape(bstring in)
{
    if(in == NULL) return NULL;

    // TODO: this isn't efficient at all, make it better
    bstring vstr = bstrcpy(in);

    // MUST GO IN THIS ORDER
    bfindreplace(vstr, &BSLASH_CHAR, &BSLASH_REPLACE, 0);
    bfindreplace(vstr, &QUOTE_CHAR, &QUOTE_REPLACE, 0);

    return vstr;
}

struct tagbstring JSON_LISTSEP = bsStatic("\",\"");

bstring Request_to_payload(Request *req, bstring uuid, int fd, const char *buf, size_t len)
{
    bstring headers = bformat("{\"%s\":\"%s\"", bdata(&HTTP_PATH), bdata(req->path));
    bstring result = NULL;
    int id = Register_id_for_fd(fd);
    bstring vstr = NULL; // used in the B macro
    bstring key = NULL;
    hnode_t *i = NULL;
    hscan_t scan;
    struct bstrList *val_list = NULL;

		//ballocmin(headers, 8192);
    check(id != -1, "Asked to generate a paylod for an fd that doesn't exist: %d", fd);

    hash_scan_begin(&scan, req->headers);
    for(i = hash_scan_next(&scan); i != NULL; i = hash_scan_next(&scan)) {
        val_list = hnode_get(i);
        key = (bstring)hnode_getkey(i);

        if(val_list->qty > 1) {
            // join all the values together as a json array then add that to the key
            bstring list = bjoin(val_list, &JSON_LISTSEP);
#if 0
            bformata(headers, ",\"%s\":[\"%s\"]", bdata(key), bdata(list));
#else
						bcatcstr(headers, ",\"");
						bcatcstr(headers, bdata(key));
						bcatcstr(headers, "\":[\"");
						bcatcstr(headers, bdata(list));
						bcatcstr(headers, "\"]");
#endif
            bdestroy(list);
        } else {
            B(key, val_list->entry[0]);
        }
    }

    // these come after so that if anyone attempts to hijack these somehow, most
    // hash algorithms languages have will replace the browser ones with ours

    if(Request_is_json(req)) {
        B(&HTTP_METHOD, &JSON_METHOD);
    } else if(Request_is_xml(req)) {
        B(&HTTP_METHOD, &XML_METHOD);
    } else {
        B(&HTTP_METHOD, req->request_method);
    }

    B(&HTTP_VERSION, req->version);
    B(&HTTP_URI, req->uri);
    B(&HTTP_QUERY, req->query_string);
    B(&HTTP_FRAGMENT, req->fragment);
    B(&HTTP_PATTERN, req->pattern);

    bconchar(headers, '}');

    result = bformat("%s %d %s %d:%s,%d:", bdata(uuid), id, 
            bdata(Request_path(req)),
            blength(headers), bdata(headers), len);

    bcatblk(result, buf, len);
    bconchar(result, ',');

    check(result, "Failed to construct payload result.");

    bdestroy(headers);
    return result;

error:
    bdestroy(headers);
    bdestroy(result);
    return NULL;
}