main: fix spurious premature parse aborts in array mode
[project/jsonpath.git] / main.c
diff --git a/main.c b/main.c
index eaa1ee09216f2b22141804831205ba847dbcbea3..a0c7b0390c41997d2b600295a202a22a1411cd5c 100644 (file)
--- a/main.c
+++ b/main.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013-2014 Jo-Philipp Wich <jow@openwrt.org>
+ * Copyright (C) 2013-2014 Jo-Philipp Wich <jo@mein.io>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -16,6 +16,7 @@
 
 #include <stdio.h>
 #include <stdbool.h>
+#include <stdint.h>
 #include <unistd.h>
 #include <errno.h>
 
@@ -37,31 +38,116 @@ struct match_item {
        struct list_head list;
 };
 
+static void
+print_usage(char *app)
+{
+       printf(
+       "== Usage ==\n\n"
+       "  # %s [-a] [-i <file> | -s \"json...\"] {-t <pattern> | -e <pattern>}\n"
+       "  -q           Quiet, no errors are printed\n"
+       "  -h, --help   Print this help\n"
+       "  -a           Implicitely treat input as array, useful for JSON logs\n"
+       "  -i path      Specify a JSON file to parse\n"
+       "  -s \"json\"  Specify a JSON string to parse\n"
+       "  -l limit     Specify max number of results to show\n"
+       "  -F separator Specify a field separator when using export\n"
+       "  -t <pattern> Print the type of values matched by pattern\n"
+       "  -e <pattern> Print the values matched by pattern\n"
+       "  -e VAR=<pat> Serialize matched value for shell \"eval\"\n\n"
+       "== Patterns ==\n\n"
+       "  Patterns are JsonPath: http://goessner.net/articles/JsonPath/\n"
+       "  This tool implements $, @, [], * and the union operator ','\n"
+       "  plus the usual expressions and literals.\n"
+       "  It does not support the recursive child search operator '..' or\n"
+       "  the '?()' and '()' filter expressions as those would require a\n"
+       "  complete JavaScript engine to support them.\n\n"
+       "== Examples ==\n\n"
+       "  Display the first IPv4 address on lan:\n"
+       "  # ifstatus lan | %s -e '@[\"ipv4-address\"][0].address'\n\n"
+       "  Extract the release string from the board information:\n"
+       "  # ubus call system board | %s -e '@.release.description'\n\n"
+       "  Find all interfaces which are up:\n"
+       "  # ubus call network.interface dump | \\\n"
+       "       %s -e '@.interface[@.up=true].interface'\n\n"
+       "  Export br-lan traffic counters for shell eval:\n"
+       "  # devstatus br-lan | %s -e 'RX=@.statistics.rx_bytes' \\\n"
+       "       -e 'TX=@.statistics.tx_bytes'\n",
+               app, app, app, app, app);
+}
+
 static struct json_object *
-parse_json(FILE *fd, const char *source, const char **error)
+parse_json_chunk(struct json_tokener *tok, struct json_object *array,
+                 const char *buf, size_t len, enum json_tokener_error *err)
 {
-       int len;
-       char buf[256];
        struct json_object *obj = NULL;
+
+       while (len)
+       {
+               obj = json_tokener_parse_ex(tok, buf, len);
+               *err = json_tokener_get_error(tok);
+
+               if (*err == json_tokener_success)
+               {
+                       if (array)
+                       {
+                               json_object_array_add(array, obj);
+                       }
+                       else
+                       {
+                               break;
+                       }
+               }
+               else if (*err != json_tokener_continue)
+               {
+                       break;
+               }
+
+               buf += tok->char_offset;
+               len -= tok->char_offset;
+       }
+
+       return obj;
+}
+
+static struct json_object *
+parse_json(FILE *fd, const char *source, const char **error, bool array_mode)
+{
+       size_t len;
+       char buf[256];
+       struct json_object *obj = NULL, *array = NULL;
        struct json_tokener *tok = json_tokener_new();
        enum json_tokener_error err = json_tokener_continue;
 
        if (!tok)
+       {
+               *error = "Out of memory";
                return NULL;
+       }
+
+       if (array_mode)
+       {
+               array = json_object_new_array();
+
+               if (!array)
+               {
+                       json_tokener_free(tok);
+                       *error = "Out of memory";
+                       return NULL;
+               }
+       }
 
        if (source)
        {
-               obj = json_tokener_parse_ex(tok, source, strlen(source));
-               err = json_tokener_get_error(tok);
+               obj = parse_json_chunk(tok, array, source, strlen(source), &err);
        }
        else
        {
                while ((len = fread(buf, 1, sizeof(buf), fd)) > 0)
                {
-                       obj = json_tokener_parse_ex(tok, buf, len);
-                       err = json_tokener_get_error(tok);
+                       obj = parse_json_chunk(tok, array, buf, len, &err);
 
-                       if (!err || err != json_tokener_continue)
+                       if ((err == json_tokener_success && array_mode == false) ||
+                           (err != json_tokener_continue && err != json_tokener_success))
                                break;
                }
        }
@@ -77,7 +163,7 @@ parse_json(FILE *fd, const char *source, const char **error)
                return NULL;
        }
 
-       return obj;
+       return array ? array : obj;
 }
 
 static void
@@ -99,10 +185,38 @@ print_string(const char *s)
 }
 
 static void
-export_value(struct list_head *matches, const char *prefix)
+print_separator(const char *sep, int *sc, int sl)
+{
+       if (*sc > 0)
+       {
+               switch (sep[(*sc - 1) % sl])
+               {
+               case '"':
+                       printf("'\"'");
+                       break;
+
+               case '\'':
+                       printf("\"'\"");
+                       break;
+
+               case ' ':
+                       printf("\\ ");
+                       break;
+
+               default:
+                       printf("%c", sep[(*sc - 1) % sl]);
+               }
+       }
+
+       (*sc)++;
+}
+
+static void
+export_value(struct list_head *matches, const char *prefix, const char *sep,
+             int limit)
 {
        int n, len;
-       bool first = true;
+       int sc = 0, sl = strlen(sep);
        struct match_item *item;
 
        if (list_empty(matches))
@@ -114,6 +228,9 @@ export_value(struct list_head *matches, const char *prefix)
 
                list_for_each_entry(item, matches, list)
                {
+                       if (limit-- <= 0)
+                               break;
+
                        switch (json_object_get_type(item->jsobj))
                        {
                        case json_type_object:
@@ -123,11 +240,8 @@ export_value(struct list_head *matches, const char *prefix)
                                        if (!val)
                                                continue;
 
-                                       if (!first)
-                                               printf("\\ ");
-
+                                       print_separator(sep, &sc, sl);
                                        print_string(key);
-                                       first = false;
                                }
                                break;
 
@@ -135,43 +249,34 @@ export_value(struct list_head *matches, const char *prefix)
                                for (n = 0, len = json_object_array_length(item->jsobj);
                                     n < len; n++)
                                {
-                                       if (!first)
-                                               printf("\\ ");
-
+                                       print_separator(sep, &sc, sl);
                                        printf("%d", n);
-                                       first = false;
                                }
                                break;
 
                        case json_type_boolean:
-                               if (!first)
-                                       printf("\\ ");
+                               print_separator(sep, &sc, sl);
                                printf("%d", json_object_get_boolean(item->jsobj));
                                break;
 
                        case json_type_int:
-                               if (!first)
-                                       printf("\\ ");
-                               printf("%d", json_object_get_int(item->jsobj));
+                               print_separator(sep, &sc, sl);
+                               printf("%" PRId64, json_object_get_int64(item->jsobj));
                                break;
 
                        case json_type_double:
-                               if (!first)
-                                       printf("\\ ");
+                               print_separator(sep, &sc, sl);
                                printf("%f", json_object_get_double(item->jsobj));
                                break;
 
                        case json_type_string:
-                               if (!first)
-                                       printf("\\ ");
+                               print_separator(sep, &sc, sl);
                                print_string(json_object_get_string(item->jsobj));
                                break;
 
                        case json_type_null:
                                break;
                        }
-
-                       first = false;
                }
 
                printf("; ");
@@ -180,6 +285,9 @@ export_value(struct list_head *matches, const char *prefix)
        {
                list_for_each_entry(item, matches, list)
                {
+                       if (limit-- <= 0)
+                               break;
+
                        switch (json_object_get_type(item->jsobj))
                        {
                        case json_type_object:
@@ -202,7 +310,7 @@ export_value(struct list_head *matches, const char *prefix)
 }
 
 static void
-export_type(struct list_head *matches, const char *prefix)
+export_type(struct list_head *matches, const char *prefix, int limit)
 {
        bool first = true;
        struct match_item *item;
@@ -227,6 +335,9 @@ export_type(struct list_head *matches, const char *prefix)
                if (!first)
                        printf("\\ ");
 
+               if (limit-- <= 0)
+                       break;
+
                printf("%s", types[json_object_get_type(item->jsobj)]);
                first = false;
        }
@@ -250,8 +361,60 @@ match_cb(struct json_object *res, void *priv)
        }
 }
 
+static void
+print_error(struct jp_state *state, char *expr)
+{
+       int i;
+       bool first = true;
+
+       fprintf(stderr, "Syntax error: ");
+
+       switch (state->error_code)
+       {
+       case -4:
+               fprintf(stderr, "Unexpected character\n");
+               break;
+
+       case -3:
+               fprintf(stderr, "String or label literal too long\n");
+               break;
+
+       case -2:
+               fprintf(stderr, "Invalid escape sequence\n");
+               break;
+
+       case -1:
+               fprintf(stderr, "Unterminated string\n");
+               break;
+
+       default:
+               for (i = 0; i < sizeof(state->error_code) * 8; i++)
+               {
+                       if (state->error_code & (1 << i))
+                       {
+                               fprintf(stderr,
+                                       first ? "Expecting %s" : " or %s", tokennames[i]);
+
+                               first = false;
+                       }
+               }
+
+               fprintf(stderr, "\n");
+               break;
+       }
+
+       fprintf(stderr, "In expression %s\n", expr);
+       fprintf(stderr, "Near here ----");
+
+       for (i = 0; i < state->error_pos; i++)
+               fprintf(stderr, "-");
+
+       fprintf(stderr, "^\n");
+}
+
 static bool
-filter_json(int opt, struct json_object *jsobj, char *expr)
+filter_json(int opt, struct json_object *jsobj, char *expr, const char *sep,
+            int limit)
 {
        struct jp_state *state;
        const char *prefix = NULL;
@@ -261,11 +424,14 @@ filter_json(int opt, struct json_object *jsobj, char *expr)
 
        state = jp_parse(expr);
 
-       if (!state || state->error)
+       if (!state)
        {
-               fprintf(stderr, "In expression '%s': %s\n",
-                       expr, state ? state->error : "Out of memory");
-
+               fprintf(stderr, "Out of memory\n");
+               goto out;
+       }
+       else if (state->error_code)
+       {
+               print_error(state, expr);
                goto out;
        }
 
@@ -277,11 +443,11 @@ filter_json(int opt, struct json_object *jsobj, char *expr)
        switch (opt)
        {
        case 't':
-               export_type(&matches, prefix);
+               export_type(&matches, prefix, limit);
                break;
 
        default:
-               export_value(&matches, prefix);
+               export_value(&matches, prefix, sep, limit);
                break;
        }
 
@@ -297,15 +463,30 @@ out:
 
 int main(int argc, char **argv)
 {
-       int opt, rv = 0;
+       bool array_mode = false;
+       int opt, rv = 0, limit = 0x7FFFFFFF;
        FILE *input = stdin;
        struct json_object *jsobj = NULL;
-       const char *jserr = NULL, *source = NULL;
+       const char *jserr = NULL, *source = NULL, *separator = " ";
 
-       while ((opt = getopt(argc, argv, "i:s:e:t:q")) != -1)
+       if (argc == 1)
+       {
+               print_usage(argv[0]);
+               goto out;
+       }
+
+       while ((opt = getopt(argc, argv, "ahi:s:e:t:F:l:q")) != -1)
        {
                switch (opt)
                {
+               case 'a':
+                       array_mode = true;
+                       break;
+
+               case 'h':
+                       print_usage(argv[0]);
+                       goto out;
+
                case 'i':
                        input = fopen(optarg, "r");
 
@@ -324,11 +505,20 @@ int main(int argc, char **argv)
                        source = optarg;
                        break;
 
+               case 'F':
+                       if (optarg && *optarg)
+                               separator = optarg;
+                       break;
+
+               case 'l':
+                       limit = atoi(optarg);
+                       break;
+
                case 't':
                case 'e':
                        if (!jsobj)
                        {
-                               jsobj = parse_json(input, source, &jserr);
+                               jsobj = parse_json(input, source, &jserr, array_mode);
 
                                if (!jsobj)
                                {
@@ -340,7 +530,7 @@ int main(int argc, char **argv)
                                }
                        }
 
-                       if (!filter_json(opt, jsobj, optarg))
+                       if (!filter_json(opt, jsobj, optarg, separator, limit))
                                rv = 1;
 
                        break;
@@ -355,7 +545,7 @@ out:
        if (jsobj)
                json_object_put(jsobj);
 
-       if (input != stdin)
+       if (input && input != stdin)
                fclose(input);
 
        return rv;