diff options
| -rw-r--r-- | lib.c | 148 | ||||
| -rw-r--r-- | tests/custom/03_stdlib/34_json | 157 |
2 files changed, 284 insertions, 21 deletions
@@ -2073,31 +2073,144 @@ uc_replace(uc_vm_t *vm, size_t nargs) return ucv_stringbuf_finish(resbuf); } -static uc_value_t * -uc_json(uc_vm_t *vm, size_t nargs) +static struct json_tokener * +uc_json_from_object(uc_vm_t *vm, uc_value_t *obj, json_object **jso) { - uc_value_t *rv = NULL, *src = uc_fn_arg(0); - struct json_tokener *tok = NULL; + bool trail = false, eof = false; enum json_tokener_error err; - json_object *jso = NULL; - const char *str; - size_t len; + struct json_tokener *tok; + uc_value_t *rfn, *rbuf; + uc_stringbuf_t *buf; + + rfn = ucv_property_get(obj, "read"); - if (ucv_type(src) != UC_STRING) { + if (!ucv_is_callable(rfn)) { uc_vm_raise_exception(vm, EXCEPTION_TYPE, - "Passed value is not a string"); + "Input object does not implement read() method"); return NULL; } tok = xjs_new_tokener(); - str = ucv_string_get(src); - len = ucv_string_length(src); + + while (true) { + uc_vm_stack_push(vm, ucv_get(obj)); + uc_vm_stack_push(vm, ucv_get(rfn)); + uc_vm_stack_push(vm, ucv_int64_new(1024)); + + if (uc_vm_call(vm, true, 1) != EXCEPTION_NONE) { + json_tokener_free(tok); + + return NULL; + } + + rbuf = uc_vm_stack_pop(vm); + + /* check EOF */ + eof = (rbuf == NULL || (ucv_type(rbuf) == UC_STRING && ucv_string_length(rbuf) == 0)); + + /* on EOF, stop parsing unless trailing garbage was detected which handled below */ + if (eof && !trail) { + ucv_put(rbuf); + + /* Didn't parse a complete object yet, possibly a non-delimitted atomic value + such as `null`, `true` etc. - nudge parser by sending final zero byte. + See json-c issue #681 <https://github.com/json-c/json-c/issues/681> */ + if (json_tokener_get_error(tok) == json_tokener_continue) + *jso = json_tokener_parse_ex(tok, "\0", 1); + + break; + } + + if (trail || *jso) { + uc_vm_raise_exception(vm, EXCEPTION_SYNTAX, + "Trailing garbage after JSON data"); + + json_tokener_free(tok); + ucv_put(rbuf); + + return NULL; + } + + if (ucv_type(rbuf) != UC_STRING) { + buf = xprintbuf_new(); + ucv_to_stringbuf_formatted(vm, buf, rbuf, 0, '\0', 0); + + *jso = json_tokener_parse_ex(tok, buf->buf, printbuf_length(buf)); + + trail = (json_tokener_get_error(tok) == json_tokener_success && + json_tokener_get_parse_end(tok) < (size_t)printbuf_length(buf)); + + printbuf_free(buf); + } + else { + *jso = json_tokener_parse_ex(tok, ucv_string_get(rbuf), ucv_string_length(rbuf)); + + trail = (json_tokener_get_error(tok) == json_tokener_success && + json_tokener_get_parse_end(tok) < ucv_string_length(rbuf)); + } + + ucv_put(rbuf); + + err = json_tokener_get_error(tok); + + if (err != json_tokener_success && err != json_tokener_continue) + break; + } + + return tok; +} + +static struct json_tokener * +uc_json_from_string(uc_vm_t *vm, uc_value_t *str, json_object **jso) +{ + struct json_tokener *tok = xjs_new_tokener(); /* NB: the len + 1 here is intentional to pass the terminating \0 byte * to the json-c parser. This is required to work-around upstream * issue #681 <https://github.com/json-c/json-c/issues/681> */ - jso = json_tokener_parse_ex(tok, str, len + 1); + *jso = json_tokener_parse_ex(tok, ucv_string_get(str), ucv_string_length(str) + 1); + + if (json_tokener_get_error(tok) == json_tokener_success && + json_tokener_get_parse_end(tok) < ucv_string_length(str)) { + uc_vm_raise_exception(vm, EXCEPTION_SYNTAX, + "Trailing garbage after JSON data"); + + json_tokener_free(tok); + + return NULL; + } + + return tok; +} + +static uc_value_t * +uc_json(uc_vm_t *vm, size_t nargs) +{ + uc_value_t *rv = NULL, *src = uc_fn_arg(0); + struct json_tokener *tok = NULL; + enum json_tokener_error err; + json_object *jso = NULL; + + switch (ucv_type(src)) { + case UC_STRING: + tok = uc_json_from_string(vm, src, &jso); + break; + + case UC_RESOURCE: + case UC_OBJECT: + case UC_ARRAY: + tok = uc_json_from_object(vm, src, &jso); + break; + + default: + uc_vm_raise_exception(vm, EXCEPTION_TYPE, + "Passed value is neither a string nor an object"); + } + + if (!tok) + goto out; + err = json_tokener_get_error(tok); if (err == json_tokener_continue) { @@ -2113,18 +2226,13 @@ uc_json(uc_vm_t *vm, size_t nargs) goto out; } - else if (json_tokener_get_parse_end(tok) < len) { - uc_vm_raise_exception(vm, EXCEPTION_SYNTAX, - "Trailing garbage after JSON data"); - - goto out; - } - rv = ucv_from_json(vm, jso); out: - json_tokener_free(tok); + if (tok) + json_tokener_free(tok); + json_object_put(jso); return rv; diff --git a/tests/custom/03_stdlib/34_json b/tests/custom/03_stdlib/34_json index ba8ad9f..c30d6d0 100644 --- a/tests/custom/03_stdlib/34_json +++ b/tests/custom/03_stdlib/34_json @@ -49,7 +49,7 @@ Passing a non-string value throws an exception. -- End -- -- Expect stderr -- -Type error: Passed value is not a string +Type error: Passed value is neither a string nor an object In line 2, byte 11: ` json(true);` @@ -108,3 +108,158 @@ In line 2, byte 28: -- End -- + + +Additionally, `json()` accepts objects implementing a read method as input. +During JSON parsing, the read method is repeatedly invoked with a buffer size +hint as sole argument. The return value of the read method is converted to a +string if needed and passed on to the JSON parser. A `null` or an empty string +return value is treated as EOF, ending the parse process. + +-- Testcase -- +{% + let fs = require("fs"); + + // parse JSON from open file handle + printf("%.J\n", + json(fs.open("files/test.json")) + ); +%} +-- End -- + +-- Expect stdout -- +{ + "hello": "world" +} +-- End -- + +-- File test.json -- +{"hello":"world"} +-- End -- + + +The `json()` function is able to parse JSON from any object providing a `read()` +method that incrementally yields JSON source data. + +-- Testcase -- +{% + let parts = [ + '{"some"', + ':', + '"object"', + ', ', + '"etc."', + ':', + !0, // this is stringified to "true" + '}' + ]; + + let producer = { + read: function(size) { + return shift(parts); + } + }; + + // parse JSON from producer object + printf("%.J\n", + json(producer) + ); +%} +-- End -- + +-- Expect stdout -- +{ + "some": "object", + "etc.": true +} +-- End -- + + +Passing objects or resources not providing a `read()` method yields an exception. + +-- Testcase -- +{% + json({}); +%} +-- End -- + +-- Expect stderr -- +Type error: Input object does not implement read() method +In line 2, byte 9: + + ` json({});` + Near here -^ + + +-- End -- + + +Exceptions triggered by the `read()` method are properly forwarded. + +-- Testcase -- +{% + json({ + read: function() { + die("Exception in read()"); + } + }); +%} +-- End -- + +-- Expect stderr -- +Exception in read() +In [anonymous function](), line 4, byte 29: + called from function json ([C]) + called from anonymous function ([stdin]:6:3) + + ` die("Exception in read()");` + Near here ---------------------------^ + + +-- End -- + + +EOF stops parsing and does not lead to further `read()` invocations. + +-- Testcase -- +{% + let parts = [ + '["some",', + '"JSON array",', + 'true,false,1,2,3', + ']', + '', // empty string treated as EOF + '{"some":', // this is not reached in the first pass + '"object"}', + null, // null treated as EOF + '"test ', // this is not reached in the second pass + 'value"' + ]; + + let producer = { read: () => shift(parts) }; + + printf("%.J\n", [ + json(producer), + json(producer), + json(producer) + ]); +%} +-- End -- + +-- Expect stdout -- +[ + [ + "some", + "JSON array", + true, + false, + 1, + 2, + 3 + ], + { + "some": "object" + }, + "test value" +] +-- End -- |