| // Copyright 2020 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| // ---------------- |
| |
| // jsonptr is discussed extensively at |
| // https://nigeltao.github.io/blog/2020/jsonptr.html |
| |
| /* |
| jsonptr is a JSON formatter (pretty-printer) that supports the JSON Pointer |
| (RFC 6901) query syntax. It reads UTF-8 JSON from stdin and writes |
| canonicalized, formatted UTF-8 JSON to stdout. |
| |
| See the "const char* g_usage" string below for details. |
| |
| ---- |
| |
| JSON Pointer (and this program's implementation) is one of many JSON query |
| languages and JSON tools, such as jq, jql and JMESPath. This one is relatively |
| simple and fewer-featured compared to those others. |
| |
| One benefit of simplicity is that this program's JSON and JSON Pointer |
| implementations do not dynamically allocate or free memory (yet it does not |
| require that the entire input fits in memory at once). They are therefore |
| trivially protected against certain bug classes: memory leaks, double-frees and |
| use-after-frees. |
| |
| The core JSON implementation is also written in the Wuffs programming language |
| (and then transpiled to C/C++), which is memory-safe (e.g. array indexing is |
| bounds-checked) but also guards against integer arithmetic overflows. |
| |
| For defense in depth, on Linux, this program also self-imposes a |
| SECCOMP_MODE_STRICT sandbox before reading (or otherwise processing) its input |
| or writing its output. Under this sandbox, the only permitted system calls are |
| read, write, exit and sigreturn. |
| |
| All together, this program aims to safely handle untrusted JSON files without |
| fear of security bugs such as remote code execution. |
| |
| ---- |
| |
| As of 2020-02-24, this program passes all 318 "test_parsing" cases from the |
| JSON test suite (https://github.com/nst/JSONTestSuite), an appendix to the |
| "Parsing JSON is a Minefield" article (http://seriot.ch/parsing_json.php) that |
| was first published on 2016-10-26 and updated on 2018-03-30. |
| |
| After modifying this program, run "build-example.sh example/jsonptr/" and then |
| "script/run-json-test-suite.sh" to catch correctness regressions. |
| |
| ---- |
| |
| This program uses Wuffs' JSON decoder at a relatively low level, processing the |
| decoder's token-stream output individually. The core loop, in pseudo-code, is |
| "for_each_token { handle_token(etc); }", where the handle_token function |
| changes global state (e.g. the `g_depth` and `g_ctx` variables) and prints |
| output text based on that state and the token's source text. Notably, |
| handle_token is not recursive, even though JSON values can nest. |
| |
| This approach is centered around JSON tokens. Each JSON 'thing' (e.g. number, |
| string, object) comprises one or more JSON tokens. |
| |
| An alternative, higher-level approach is in the sibling example/jsonfindptrs |
| program. Neither approach is better or worse per se, but when studying this |
| program, be aware that there are multiple ways to use Wuffs' JSON decoder. |
| |
| The two programs, jsonfindptrs and jsonptr, also demonstrate different |
| trade-offs with regard to JSON object duplicate keys. The JSON spec permits |
| different implementations to allow or reject duplicate keys. It is not always |
| clear which approach is safer. Rejecting them is certainly unambiguous, and |
| security bugs can lurk in ambiguous corners of a file format, if two different |
| implementations both silently accept a file but differ on how to interpret it. |
| On the other hand, in the worst case, detecting duplicate keys requires O(N) |
| memory, where N is the size of the (potentially untrusted) input. |
| |
| This program (jsonptr) allows duplicate keys and requires only O(1) memory. As |
| mentioned above, it doesn't dynamically allocate memory at all, and on Linux, |
| it runs in a SECCOMP_MODE_STRICT sandbox. |
| |
| ---- |
| |
| To run: |
| |
| $CXX jsonptr.cc && ./a.out < ../../test/data/github-tags.json; rm -f a.out |
| |
| for a C++ compiler $CXX, such as clang++ or g++. |
| */ |
| |
| #if defined(__cplusplus) && (__cplusplus < 201103L) |
| #error "This C++ program requires -std=c++11 or later" |
| #endif |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| // Wuffs ships as a "single file C library" or "header file library" as per |
| // https://github.com/nothings/stb/blob/master/docs/stb_howto.txt |
| // |
| // To use that single file as a "foo.c"-like implementation, instead of a |
| // "foo.h"-like header, #define WUFFS_IMPLEMENTATION before #include'ing or |
| // compiling it. |
| #define WUFFS_IMPLEMENTATION |
| |
| // Defining the WUFFS_CONFIG__MODULE* macros are optional, but it lets users of |
| // release/c/etc.c choose which parts of Wuffs to build. That file contains the |
| // entire Wuffs standard library, implementing a variety of codecs and file |
| // formats. Without this macro definition, an optimizing compiler or linker may |
| // very well discard Wuffs code for unused codecs, but listing the Wuffs |
| // modules we use makes that process explicit. Preprocessing means that such |
| // code simply isn't compiled. |
| #define WUFFS_CONFIG__MODULES |
| #define WUFFS_CONFIG__MODULE__BASE |
| #define WUFFS_CONFIG__MODULE__JSON |
| |
| // If building this program in an environment that doesn't easily accommodate |
| // relative includes, you can use the script/inline-c-relative-includes.go |
| // program to generate a stand-alone C++ file. |
| #include "../../release/c/wuffs-unsupported-snapshot.c" |
| |
| #if defined(__linux__) |
| #include <linux/prctl.h> |
| #include <linux/seccomp.h> |
| #include <sys/prctl.h> |
| #include <sys/syscall.h> |
| #define WUFFS_EXAMPLE_USE_SECCOMP |
| #endif |
| |
| #define TRY(error_msg) \ |
| do { \ |
| const char* z = error_msg; \ |
| if (z) { \ |
| return z; \ |
| } \ |
| } while (false) |
| |
| static const char* g_eod = "main: end of data"; |
| |
| static const char* g_usage = |
| "Usage: jsonptr -flags input.json\n" |
| "\n" |
| "Flags:\n" |
| " -c -compact-output\n" |
| " -d=NUM -max-output-depth=NUM\n" |
| " -q=STR -query=STR\n" |
| " -s=NUM -spaces=NUM\n" |
| " -t -tabs\n" |
| " -fail-if-unsandboxed\n" |
| " -input-allow-comments\n" |
| " -input-allow-extra-comma\n" |
| " -input-allow-inf-nan-numbers\n" |
| " -input-jwcc\n" |
| " -jwcc\n" |
| " -output-comments\n" |
| " -output-extra-comma\n" |
| " -output-inf-nan-numbers\n" |
| " -strict-json-pointer-syntax\n" |
| "\n" |
| "The input.json filename is optional. If absent, it reads from stdin.\n" |
| "\n" |
| "----\n" |
| "\n" |
| "jsonptr is a JSON formatter (pretty-printer) that supports the JSON\n" |
| "Pointer (RFC 6901) query syntax. It reads UTF-8 JSON from stdin and\n" |
| "writes canonicalized, formatted UTF-8 JSON to stdout.\n" |
| "\n" |
| "Canonicalized means that e.g. \"abc\\u000A\\tx\\u0177z\" is re-written\n" |
| "as \"abc\\n\\txŷz\". It does not sort object keys, nor does it reject\n" |
| "duplicate keys. Canonicalization does not imply Unicode normalization.\n" |
| "\n" |
| "Formatted means that arrays' and objects' elements are indented, each\n" |
| "on its own line. Configure this with the -c / -compact-output, -s=NUM /\n" |
| "-spaces=NUM (for NUM ranging from 0 to 8) and -t / -tabs flags.\n" |
| "\n" |
| "The -input-allow-comments flag allows \"/*slash-star*/\" and\n" |
| "\"//slash-slash\" C-style comments within JSON input. Such comments are\n" |
| "stripped from the output unless -output-comments was also set.\n" |
| "\n" |
| "The -input-allow-extra-comma flag allows input like \"[1,2,]\", with a\n" |
| "comma after the final element of a JSON list or dictionary.\n" |
| "\n" |
| "The -input-allow-inf-nan-numbers flag allows non-finite floating point\n" |
| "numbers (infinities and not-a-numbers) within JSON input. This flag\n" |
| "requires that -output-inf-nan-numbers also be set.\n" |
| "\n" |
| "The -output-comments flag copies any input comments to the output. It\n" |
| "has no effect unless -input-allow-comments was also set. Comments look\n" |
| "better after commas than before them, but a closing \"]\" or \"}\" can\n" |
| "occur after arbitrarily many comments, so -output-comments also requires\n" |
| "that one or both of -compact-output and -output-extra-comma be set.\n" |
| "\n" |
| "With -output-comments, consecutive blank lines collapse to a single\n" |
| "blank line. Without that flag, all blank lines are removed.\n" |
| "\n" |
| "The -output-extra-comma flag writes output like \"[1,2,]\", with a comma\n" |
| "after the final element of a JSON list or dictionary. Such commas are\n" |
| "non-compliant with the JSON specification but many parsers accept them\n" |
| "and they can produce simpler line-based diffs. This flag is ignored when\n" |
| "-compact-output is set.\n" |
| "\n" |
| "Combining some of those flags results in speaking JWCC (JSON With Commas\n" |
| "and Comments), not plain JSON. For convenience, the -input-jwcc or -jwcc\n" |
| "flags enables the first two or all four of:\n" |
| " -input-allow-comments\n" |
| " -input-allow-extra-comma\n" |
| " -output-comments\n" |
| " -output-extra-comma\n" |
| "\n" |
| #if defined(WUFFS_EXAMPLE_SPEAK_JWCC_NOT_JSON) |
| "This program was configured at compile time to always use -jwcc.\n" |
| "\n" |
| #endif |
| "----\n" |
| "\n" |
| "The -q=STR or -query=STR flag gives an optional JSON Pointer query, to\n" |
| "print a subset of the input. For example, given RFC 6901 section 5's\n" |
| "sample input (https://tools.ietf.org/rfc/rfc6901.txt), this command:\n" |
| " jsonptr -query=/foo/1 rfc-6901-json-pointer.json\n" |
| "will print:\n" |
| " \"baz\"\n" |
| "\n" |
| "An absent query is equivalent to the empty query, which identifies the\n" |
| "entire input (the root value). Unlike a file system, the \"/\" query\n" |
| "does not identify the root. Instead, \"\" is the root and \"/\" is the\n" |
| "child (the value in a key-value pair) of the root whose key is the empty\n" |
| "string. Similarly, \"/xyz\" and \"/xyz/\" are two different nodes.\n" |
| "\n" |
| "If the query found a valid JSON value, this program will return a zero\n" |
| "exit code even if the rest of the input isn't valid JSON. If the query\n" |
| "did not find a value, or found an invalid one, this program returns a\n" |
| "non-zero exit code, but may still print partial output to stdout.\n" |
| "\n" |
| "The JSON specification (https://json.org/) permits implementations that\n" |
| "allow duplicate keys, as this one does. This JSON Pointer implementation\n" |
| "is also greedy, following the first match for each fragment without\n" |
| "back-tracking. For example, the \"/foo/bar\" query will fail if the root\n" |
| "object has multiple \"foo\" children but the first one doesn't have a\n" |
| "\"bar\" child, even if later ones do.\n" |
| "\n" |
| "The -strict-json-pointer-syntax flag restricts the -query=STR string to\n" |
| "exactly RFC 6901, with only two escape sequences: \"~0\" and \"~1\" for\n" |
| "\"~\" and \"/\". Without this flag, this program also lets \"~n\",\n" |
| "\"~r\" and \"~t\" escape the New Line, Carriage Return and Horizontal\n" |
| "Tab ASCII control characters, which can work better with line oriented\n" |
| "(and tab separated) Unix tools that assume exactly one record (e.g. one\n" |
| "JSON Pointer string) per line.\n" |
| "\n" |
| "----\n" |
| "\n" |
| "The -d=NUM or -max-output-depth=NUM flag gives the maximum (inclusive)\n" |
| "output depth. JSON containers ([] arrays and {} objects) can hold other\n" |
| "containers. When this flag is set, containers at depth NUM are replaced\n" |
| "with \"[…]\" or \"{…}\". A bare -d or -max-output-depth is equivalent to\n" |
| "-d=1. The flag's absence is equivalent to an unlimited output depth.\n" |
| "\n" |
| "The -max-output-depth flag only affects the program's output. It doesn't\n" |
| "affect whether or not the input is considered valid JSON. The JSON\n" |
| "specification permits implementations to set their own maximum input\n" |
| "depth. This JSON implementation sets it to 1024.\n" |
| "\n" |
| "Depth is measured in terms of nested containers. It is unaffected by the\n" |
| "number of spaces or tabs used to indent.\n" |
| "\n" |
| "When both -max-output-depth and -query are set, the output depth is\n" |
| "measured from when the query resolves, not from the input root. The\n" |
| "input depth (measured from the root) is still limited to 1024.\n" |
| "\n" |
| "----\n" |
| "\n" |
| "The -fail-if-unsandboxed flag causes the program to exit if it does not\n" |
| "self-impose a sandbox. On Linux, it self-imposes a SECCOMP_MODE_STRICT\n" |
| "sandbox, regardless of whether this flag was set."; |
| |
| // ---- |
| |
| // ascii_escapes was created by script/print-json-ascii-escapes.go. |
| const uint8_t ascii_escapes[1024] = { |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x30, 0x00, // 0x00: "\\u0000" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x31, 0x00, // 0x01: "\\u0001" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x32, 0x00, // 0x02: "\\u0002" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x33, 0x00, // 0x03: "\\u0003" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x34, 0x00, // 0x04: "\\u0004" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x35, 0x00, // 0x05: "\\u0005" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x36, 0x00, // 0x06: "\\u0006" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x37, 0x00, // 0x07: "\\u0007" |
| 0x02, 0x5C, 0x62, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x08: "\\b" |
| 0x02, 0x5C, 0x74, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x09: "\\t" |
| 0x02, 0x5C, 0x6E, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x0A: "\\n" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x42, 0x00, // 0x0B: "\\u000B" |
| 0x02, 0x5C, 0x66, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x0C: "\\f" |
| 0x02, 0x5C, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x0D: "\\r" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x45, 0x00, // 0x0E: "\\u000E" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x30, 0x46, 0x00, // 0x0F: "\\u000F" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x30, 0x00, // 0x10: "\\u0010" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x31, 0x00, // 0x11: "\\u0011" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x32, 0x00, // 0x12: "\\u0012" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x33, 0x00, // 0x13: "\\u0013" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x34, 0x00, // 0x14: "\\u0014" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x35, 0x00, // 0x15: "\\u0015" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x36, 0x00, // 0x16: "\\u0016" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x37, 0x00, // 0x17: "\\u0017" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x38, 0x00, // 0x18: "\\u0018" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x39, 0x00, // 0x19: "\\u0019" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x41, 0x00, // 0x1A: "\\u001A" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x42, 0x00, // 0x1B: "\\u001B" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x43, 0x00, // 0x1C: "\\u001C" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x44, 0x00, // 0x1D: "\\u001D" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x45, 0x00, // 0x1E: "\\u001E" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x31, 0x46, 0x00, // 0x1F: "\\u001F" |
| 0x06, 0x5C, 0x75, 0x30, 0x30, 0x32, 0x30, 0x00, // 0x20: "\\u0020" |
| 0x01, 0x21, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x21: "!" |
| 0x02, 0x5C, 0x22, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x22: "\\\"" |
| 0x01, 0x23, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x23: "#" |
| 0x01, 0x24, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x24: "$" |
| 0x01, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x25: "%" |
| 0x01, 0x26, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x26: "&" |
| 0x01, 0x27, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x27: "'" |
| 0x01, 0x28, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x28: "(" |
| 0x01, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x29: ")" |
| 0x01, 0x2A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2A: "*" |
| 0x01, 0x2B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2B: "+" |
| 0x01, 0x2C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2C: "," |
| 0x01, 0x2D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2D: "-" |
| 0x01, 0x2E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2E: "." |
| 0x01, 0x2F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x2F: "/" |
| 0x01, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x30: "0" |
| 0x01, 0x31, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x31: "1" |
| 0x01, 0x32, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x32: "2" |
| 0x01, 0x33, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x33: "3" |
| 0x01, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x34: "4" |
| 0x01, 0x35, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x35: "5" |
| 0x01, 0x36, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x36: "6" |
| 0x01, 0x37, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x37: "7" |
| 0x01, 0x38, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x38: "8" |
| 0x01, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x39: "9" |
| 0x01, 0x3A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3A: ":" |
| 0x01, 0x3B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3B: ";" |
| 0x01, 0x3C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3C: "<" |
| 0x01, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3D: "=" |
| 0x01, 0x3E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3E: ">" |
| 0x01, 0x3F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x3F: "?" |
| 0x01, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x40: "@" |
| 0x01, 0x41, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x41: "A" |
| 0x01, 0x42, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x42: "B" |
| 0x01, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x43: "C" |
| 0x01, 0x44, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x44: "D" |
| 0x01, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x45: "E" |
| 0x01, 0x46, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x46: "F" |
| 0x01, 0x47, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x47: "G" |
| 0x01, 0x48, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x48: "H" |
| 0x01, 0x49, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x49: "I" |
| 0x01, 0x4A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4A: "J" |
| 0x01, 0x4B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4B: "K" |
| 0x01, 0x4C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4C: "L" |
| 0x01, 0x4D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4D: "M" |
| 0x01, 0x4E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4E: "N" |
| 0x01, 0x4F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x4F: "O" |
| 0x01, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x50: "P" |
| 0x01, 0x51, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x51: "Q" |
| 0x01, 0x52, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x52: "R" |
| 0x01, 0x53, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x53: "S" |
| 0x01, 0x54, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x54: "T" |
| 0x01, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x55: "U" |
| 0x01, 0x56, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x56: "V" |
| 0x01, 0x57, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x57: "W" |
| 0x01, 0x58, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x58: "X" |
| 0x01, 0x59, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x59: "Y" |
| 0x01, 0x5A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5A: "Z" |
| 0x01, 0x5B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5B: "[" |
| 0x02, 0x5C, 0x5C, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5C: "\\\\" |
| 0x01, 0x5D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5D: "]" |
| 0x01, 0x5E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5E: "^" |
| 0x01, 0x5F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x5F: "_" |
| 0x01, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x60: "`" |
| 0x01, 0x61, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x61: "a" |
| 0x01, 0x62, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x62: "b" |
| 0x01, 0x63, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x63: "c" |
| 0x01, 0x64, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x64: "d" |
| 0x01, 0x65, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x65: "e" |
| 0x01, 0x66, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x66: "f" |
| 0x01, 0x67, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x67: "g" |
| 0x01, 0x68, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x68: "h" |
| 0x01, 0x69, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x69: "i" |
| 0x01, 0x6A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6A: "j" |
| 0x01, 0x6B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6B: "k" |
| 0x01, 0x6C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6C: "l" |
| 0x01, 0x6D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6D: "m" |
| 0x01, 0x6E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6E: "n" |
| 0x01, 0x6F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x6F: "o" |
| 0x01, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x70: "p" |
| 0x01, 0x71, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x71: "q" |
| 0x01, 0x72, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x72: "r" |
| 0x01, 0x73, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x73: "s" |
| 0x01, 0x74, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x74: "t" |
| 0x01, 0x75, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x75: "u" |
| 0x01, 0x76, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x76: "v" |
| 0x01, 0x77, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x77: "w" |
| 0x01, 0x78, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x78: "x" |
| 0x01, 0x79, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x79: "y" |
| 0x01, 0x7A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7A: "z" |
| 0x01, 0x7B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7B: "{" |
| 0x01, 0x7C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7C: "|" |
| 0x01, 0x7D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7D: "}" |
| 0x01, 0x7E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7E: "~" |
| 0x01, 0x7F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // 0x7F: "<DEL>" |
| }; |
| |
| // Wuffs allows either statically or dynamically allocated work buffers. This |
| // program exercises static allocation. |
| #define WORK_BUFFER_ARRAY_SIZE \ |
| WUFFS_JSON__DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE |
| #if WORK_BUFFER_ARRAY_SIZE > 0 |
| uint8_t g_work_buffer_array[WORK_BUFFER_ARRAY_SIZE]; |
| #else |
| // Not all C/C++ compilers support 0-length arrays. |
| uint8_t g_work_buffer_array[1]; |
| #endif |
| |
| bool g_sandboxed = false; |
| |
| int g_input_file_descriptor = 0; // A 0 default means stdin. |
| |
| #define TWO_NEW_LINES_THEN_256_SPACES \ |
| "\n\n " \ |
| " " \ |
| " " \ |
| " " |
| #define TWO_NEW_LINES_THEN_256_TABS \ |
| "\n\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" \ |
| "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t" |
| |
| const char* g_two_new_lines_then_256_indent_bytes; |
| uint32_t g_bytes_per_indent_depth; |
| |
| #ifndef DST_BUFFER_ARRAY_SIZE |
| #define DST_BUFFER_ARRAY_SIZE (32 * 1024) |
| #endif |
| #ifndef SRC_BUFFER_ARRAY_SIZE |
| #define SRC_BUFFER_ARRAY_SIZE (32 * 1024) |
| #endif |
| // 1 token is 8 bytes. 4Ki tokens is 32KiB. |
| #ifndef TOKEN_BUFFER_ARRAY_SIZE |
| #define TOKEN_BUFFER_ARRAY_SIZE (4 * 1024) |
| #endif |
| |
| uint8_t g_dst_array[DST_BUFFER_ARRAY_SIZE]; |
| uint8_t g_src_array[SRC_BUFFER_ARRAY_SIZE]; |
| wuffs_base__token g_tok_array[TOKEN_BUFFER_ARRAY_SIZE]; |
| |
| wuffs_base__io_buffer g_dst; |
| wuffs_base__io_buffer g_src; |
| wuffs_base__token_buffer g_tok; |
| |
| // g_cursor_index is the g_src.data.ptr index between the previous and current |
| // token. An invariant is that (g_cursor_index <= g_src.meta.ri). |
| size_t g_cursor_index; |
| |
| uint32_t g_depth; |
| |
| enum class context { |
| none, |
| in_list_after_bracket, |
| in_list_after_value, |
| in_dict_after_brace, |
| in_dict_after_key, |
| in_dict_after_value, |
| end_of_data, |
| } g_ctx; |
| |
| bool // |
| in_dict_before_key() { |
| return (g_ctx == context::in_dict_after_brace) || |
| (g_ctx == context::in_dict_after_value); |
| } |
| |
| uint64_t g_num_input_blank_lines; |
| |
| bool g_is_after_comment; |
| |
| uint32_t g_suppress_write_dst; |
| bool g_wrote_to_dst; |
| |
| wuffs_json__decoder g_dec; |
| |
| // ---- |
| |
| // Query is a JSON Pointer query. After initializing with a NUL-terminated C |
| // string, its multiple fragments are consumed as the program walks the JSON |
| // data from stdin. For example, letting "$" denote a NUL, suppose that we |
| // started with a query string of "/apple/banana/12/durian" and are currently |
| // trying to match the second fragment, "banana", so that Query::m_depth is 2: |
| // |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // / a p p l e / b a n a n a / 1 2 / d u r i a n $ |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // ^ ^ |
| // m_frag_i m_frag_k |
| // |
| // The two pointers m_frag_i and m_frag_k (abbreviated as mfi and mfk) are the |
| // start (inclusive) and end (exclusive) of the query fragment. They satisfy |
| // (mfi <= mfk) and may be equal if the fragment empty (note that "" is a valid |
| // JSON object key). |
| // |
| // The m_frag_j (mfj) pointer moves between these two, or is nullptr. An |
| // invariant is that (((mfi <= mfj) && (mfj <= mfk)) || (mfj == nullptr)). |
| // |
| // Wuffs' JSON tokenizer can portray a single JSON string as multiple Wuffs |
| // tokens, as backslash-escaped values within that JSON string may each get |
| // their own token. |
| // |
| // At the start of each object key (a JSON string), mfj is set to mfi. |
| // |
| // While mfj remains non-nullptr, each token's unescaped contents are then |
| // compared to that part of the fragment from mfj to mfk. If it is a prefix |
| // (including the case of an exact match), then mfj is advanced by the |
| // unescaped length. Otherwise, mfj is set to nullptr. |
| // |
| // Comparison accounts for JSON Pointer's escaping notation: "~0" and "~1" in |
| // the query (not the JSON value) are unescaped to "~" and "/" respectively. |
| // "~n" and "~r" are also unescaped to "\n" and "\r". The program is |
| // responsible for calling Query::validate (with a strict_json_pointer_syntax |
| // argument) before otherwise using this class. |
| // |
| // The mfj pointer therefore advances from mfi to mfk, or drops out, as we |
| // incrementally match the object key with the query fragment. For example, if |
| // we have already matched the "ban" of "banana", then we would accept any of |
| // an "ana" token, an "a" token or a "\u0061" token, amongst others. They would |
| // advance mfj by 3, 1 or 1 bytes respectively. |
| // |
| // mfj |
| // v |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // / a p p l e / b a n a n a / 1 2 / d u r i a n $ |
| // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| // ^ ^ |
| // mfi mfk |
| // |
| // At the end of each object key (or equivalently, at the start of each object |
| // value), if mfj is non-nullptr and equal to (but not less than) mfk then we |
| // have a fragment match: the query fragment equals the object key. If there is |
| // a next fragment (in this example, "12") we move the frag_etc pointers to its |
| // start and end and increment Query::m_depth. Otherwise, we have matched the |
| // complete query, and the upcoming JSON value is the result of that query. |
| // |
| // The discussion above centers on object keys. If the query fragment is |
| // numeric then it can also match as an array index: the string fragment "12" |
| // will match an array's 13th element (starting counting from zero). See RFC |
| // 6901 for its precise definition of an "array index" number. |
| // |
| // Array index fragment match is represented by the Query::m_array_index field, |
| // whose type (wuffs_base__result_u64) is a result type. An error result means |
| // that the fragment is not an array index. A value result holds the number of |
| // list elements remaining. When matching a query fragment in an array (instead |
| // of in an object), each element ticks this number down towards zero. At zero, |
| // the upcoming JSON value is the one that matches the query fragment. |
| class Query { |
| private: |
| uint8_t* m_frag_i; |
| uint8_t* m_frag_j; |
| uint8_t* m_frag_k; |
| |
| uint32_t m_depth; |
| |
| wuffs_base__result_u64 m_array_index; |
| |
| public: |
| void reset(char* query_c_string) { |
| m_frag_i = (uint8_t*)query_c_string; |
| m_frag_j = (uint8_t*)query_c_string; |
| m_frag_k = (uint8_t*)query_c_string; |
| m_depth = 0; |
| m_array_index.status.repr = "#main: not an array index query fragment"; |
| m_array_index.value = 0; |
| } |
| |
| void restart_fragment(bool enable) { m_frag_j = enable ? m_frag_i : nullptr; } |
| |
| bool is_at(uint32_t depth) { return m_depth == depth; } |
| |
| // tick returns whether the fragment is a valid array index whose value is |
| // zero. If valid but non-zero, it decrements it and returns false. |
| bool tick() { |
| if (m_array_index.status.is_ok()) { |
| if (m_array_index.value == 0) { |
| return true; |
| } |
| m_array_index.value--; |
| } |
| return false; |
| } |
| |
| // next_fragment moves to the next fragment, returning whether it existed. |
| bool next_fragment() { |
| uint8_t* k = m_frag_k; |
| uint32_t d = m_depth; |
| |
| this->reset(nullptr); |
| |
| if (!k || (*k != '/')) { |
| return false; |
| } |
| k++; |
| |
| bool all_digits = true; |
| uint8_t* i = k; |
| while ((*k != '\x00') && (*k != '/')) { |
| all_digits = all_digits && ('0' <= *k) && (*k <= '9'); |
| k++; |
| } |
| m_frag_i = i; |
| m_frag_j = i; |
| m_frag_k = k; |
| m_depth = d + 1; |
| if (all_digits) { |
| // wuffs_base__parse_number_u64 rejects leading zeroes, e.g. "00", "07". |
| m_array_index = wuffs_base__parse_number_u64( |
| wuffs_base__make_slice_u8(i, k - i), |
| WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS); |
| } |
| return true; |
| } |
| |
| bool matched_all() { return m_frag_k == nullptr; } |
| |
| bool matched_fragment() { return m_frag_j && (m_frag_j == m_frag_k); } |
| |
| void incremental_match_slice(uint8_t* ptr, size_t len) { |
| if (!m_frag_j) { |
| return; |
| } |
| uint8_t* j = m_frag_j; |
| while (true) { |
| if (len == 0) { |
| m_frag_j = j; |
| return; |
| } |
| |
| if (*j == '\x00') { |
| break; |
| |
| } else if (*j == '~') { |
| j++; |
| if (*j == '0') { |
| if (*ptr != '~') { |
| break; |
| } |
| } else if (*j == '1') { |
| if (*ptr != '/') { |
| break; |
| } |
| } else if (*j == 'n') { |
| if (*ptr != '\n') { |
| break; |
| } |
| } else if (*j == 'r') { |
| if (*ptr != '\r') { |
| break; |
| } |
| } else if (*j == 't') { |
| if (*ptr != '\t') { |
| break; |
| } |
| } else { |
| break; |
| } |
| |
| } else if (*j != *ptr) { |
| break; |
| } |
| |
| j++; |
| ptr++; |
| len--; |
| } |
| m_frag_j = nullptr; |
| } |
| |
| void incremental_match_code_point(uint32_t code_point) { |
| if (!m_frag_j) { |
| return; |
| } |
| uint8_t u[WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL]; |
| size_t n = wuffs_base__utf_8__encode( |
| wuffs_base__make_slice_u8(&u[0], |
| WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL), |
| code_point); |
| if (n > 0) { |
| this->incremental_match_slice(&u[0], n); |
| } |
| } |
| |
| // validate returns whether the (ptr, len) arguments form a valid JSON |
| // Pointer. In particular, it must be valid UTF-8, and either be empty or |
| // start with a '/'. Any '~' within must immediately be followed by either |
| // '0' or '1'. If strict_json_pointer_syntax is false, a '~' may also be |
| // followed by either 'n', 'r' or 't'. |
| static bool validate(char* query_c_string, |
| size_t length, |
| bool strict_json_pointer_syntax) { |
| if (length <= 0) { |
| return true; |
| } |
| if (query_c_string[0] != '/') { |
| return false; |
| } |
| wuffs_base__slice_u8 s = |
| wuffs_base__make_slice_u8((uint8_t*)query_c_string, length); |
| bool previous_was_tilde = false; |
| while (s.len > 0) { |
| wuffs_base__utf_8__next__output o = wuffs_base__utf_8__next(s.ptr, s.len); |
| if (!o.is_valid()) { |
| return false; |
| } |
| |
| if (previous_was_tilde) { |
| switch (o.code_point) { |
| case '0': |
| case '1': |
| break; |
| case 'n': |
| case 'r': |
| case 't': |
| if (strict_json_pointer_syntax) { |
| return false; |
| } |
| break; |
| default: |
| return false; |
| } |
| } |
| previous_was_tilde = o.code_point == '~'; |
| |
| s.ptr += o.byte_length; |
| s.len -= o.byte_length; |
| } |
| return !previous_was_tilde; |
| } |
| } g_query; |
| |
| // ---- |
| |
| struct { |
| int remaining_argc; |
| char** remaining_argv; |
| |
| bool compact_output; |
| bool fail_if_unsandboxed; |
| bool input_allow_comments; |
| bool input_allow_extra_comma; |
| bool input_allow_inf_nan_numbers; |
| bool output_comments; |
| bool output_extra_comma; |
| bool output_inf_nan_numbers; |
| bool strict_json_pointer_syntax; |
| bool tabs; |
| |
| uint32_t max_output_depth; |
| uint32_t spaces; |
| |
| char* query_c_string; |
| } g_flags = {0}; |
| |
| const char* // |
| parse_flags(int argc, char** argv) { |
| g_flags.spaces = 4; |
| g_flags.max_output_depth = 0xFFFFFFFF; |
| |
| #if defined(WUFFS_EXAMPLE_SPEAK_JWCC_NOT_JSON) |
| g_flags.input_allow_comments = true; |
| g_flags.input_allow_extra_comma = true; |
| g_flags.output_comments = true; |
| g_flags.output_extra_comma = true; |
| #endif |
| |
| int c = (argc > 0) ? 1 : 0; // Skip argv[0], the program name. |
| for (; c < argc; c++) { |
| char* arg = argv[c]; |
| if (*arg++ != '-') { |
| break; |
| } |
| |
| // A double-dash "--foo" is equivalent to a single-dash "-foo". As special |
| // cases, a bare "-" is not a flag (some programs may interpret it as |
| // stdin) and a bare "--" means to stop parsing flags. |
| if (*arg == '\x00') { |
| break; |
| } else if (*arg == '-') { |
| arg++; |
| if (*arg == '\x00') { |
| c++; |
| break; |
| } |
| } |
| |
| if (!strcmp(arg, "c") || !strcmp(arg, "compact-output")) { |
| g_flags.compact_output = true; |
| continue; |
| } |
| if (!strcmp(arg, "d") || !strcmp(arg, "max-output-depth")) { |
| g_flags.max_output_depth = 1; |
| continue; |
| } else if (!strncmp(arg, "d=", 2) || |
| !strncmp(arg, "max-output-depth=", 16)) { |
| while (*arg++ != '=') { |
| } |
| wuffs_base__result_u64 u = wuffs_base__parse_number_u64( |
| wuffs_base__make_slice_u8((uint8_t*)arg, strlen(arg)), |
| WUFFS_BASE__PARSE_NUMBER_XXX__DEFAULT_OPTIONS); |
| if (u.status.is_ok() && (u.value <= 0xFFFFFFFF)) { |
| g_flags.max_output_depth = (uint32_t)(u.value); |
| continue; |
| } |
| return g_usage; |
| } |
| if (!strcmp(arg, "fail-if-unsandboxed")) { |
| g_flags.fail_if_unsandboxed = true; |
| continue; |
| } |
| if (!strcmp(arg, "input-allow-comments")) { |
| g_flags.input_allow_comments = true; |
| continue; |
| } |
| if (!strcmp(arg, "input-allow-extra-comma")) { |
| g_flags.input_allow_extra_comma = true; |
| continue; |
| } |
| if (!strcmp(arg, "input-allow-inf-nan-numbers")) { |
| g_flags.input_allow_inf_nan_numbers = true; |
| continue; |
| } |
| if (!strcmp(arg, "input-jwcc")) { |
| g_flags.input_allow_comments = true; |
| g_flags.input_allow_extra_comma = true; |
| continue; |
| } |
| if (!strcmp(arg, "jwcc")) { |
| g_flags.input_allow_comments = true; |
| g_flags.input_allow_extra_comma = true; |
| g_flags.output_comments = true; |
| g_flags.output_extra_comma = true; |
| continue; |
| } |
| if (!strcmp(arg, "output-comments")) { |
| g_flags.output_comments = true; |
| continue; |
| } |
| if (!strcmp(arg, "output-extra-comma")) { |
| g_flags.output_extra_comma = true; |
| continue; |
| } |
| if (!strcmp(arg, "output-inf-nan-numbers")) { |
| g_flags.output_inf_nan_numbers = true; |
| continue; |
| } |
| if (!strncmp(arg, "q=", 2) || !strncmp(arg, "query=", 6)) { |
| while (*arg++ != '=') { |
| } |
| g_flags.query_c_string = arg; |
| continue; |
| } |
| if (!strncmp(arg, "s=", 2) || !strncmp(arg, "spaces=", 7)) { |
| while (*arg++ != '=') { |
| } |
| if (('0' <= arg[0]) && (arg[0] <= '8') && (arg[1] == '\x00')) { |
| g_flags.spaces = arg[0] - '0'; |
| continue; |
| } |
| return g_usage; |
| } |
| if (!strcmp(arg, "strict-json-pointer-syntax")) { |
| g_flags.strict_json_pointer_syntax = true; |
| continue; |
| } |
| if (!strcmp(arg, "t") || !strcmp(arg, "tabs")) { |
| g_flags.tabs = true; |
| continue; |
| } |
| |
| return g_usage; |
| } |
| |
| if (g_flags.query_c_string && |
| !Query::validate(g_flags.query_c_string, strlen(g_flags.query_c_string), |
| g_flags.strict_json_pointer_syntax)) { |
| return "main: bad JSON Pointer (RFC 6901) syntax for the -query=STR flag"; |
| } |
| |
| g_flags.remaining_argc = argc - c; |
| g_flags.remaining_argv = argv + c; |
| return nullptr; |
| } |
| |
| const char* // |
| initialize_globals(int argc, char** argv) { |
| g_dst = wuffs_base__make_io_buffer( |
| wuffs_base__make_slice_u8(g_dst_array, DST_BUFFER_ARRAY_SIZE), |
| wuffs_base__empty_io_buffer_meta()); |
| |
| g_src = wuffs_base__make_io_buffer( |
| wuffs_base__make_slice_u8(g_src_array, SRC_BUFFER_ARRAY_SIZE), |
| wuffs_base__empty_io_buffer_meta()); |
| |
| g_tok = wuffs_base__make_token_buffer( |
| wuffs_base__make_slice_token(g_tok_array, TOKEN_BUFFER_ARRAY_SIZE), |
| wuffs_base__empty_token_buffer_meta()); |
| |
| g_cursor_index = 0; |
| |
| g_depth = 0; |
| |
| g_ctx = context::none; |
| |
| g_num_input_blank_lines = 0; |
| |
| g_is_after_comment = false; |
| |
| TRY(parse_flags(argc, argv)); |
| if (g_flags.fail_if_unsandboxed && !g_sandboxed) { |
| return "main: unsandboxed"; |
| } |
| if (g_flags.output_comments && !g_flags.compact_output && |
| !g_flags.output_extra_comma) { |
| return "main: -output-comments requires one or both of -compact-output and " |
| "-output-extra-comma"; |
| } |
| if (g_flags.input_allow_inf_nan_numbers && !g_flags.output_inf_nan_numbers) { |
| return "main: -input-allow-inf-nan-numbers requires " |
| "-output-inf-nan-numbers"; |
| } |
| const int stdin_fd = 0; |
| if (g_flags.remaining_argc > |
| ((g_input_file_descriptor != stdin_fd) ? 1 : 0)) { |
| return g_usage; |
| } |
| |
| g_two_new_lines_then_256_indent_bytes = g_flags.tabs |
| ? TWO_NEW_LINES_THEN_256_TABS |
| : TWO_NEW_LINES_THEN_256_SPACES; |
| g_bytes_per_indent_depth = g_flags.tabs ? 1 : g_flags.spaces; |
| |
| g_query.reset(g_flags.query_c_string); |
| |
| // If the query is non-empty, suppress writing to stdout until we've |
| // completed the query. |
| g_suppress_write_dst = g_query.next_fragment() ? 1 : 0; |
| g_wrote_to_dst = false; |
| |
| TRY(g_dec.initialize(sizeof__wuffs_json__decoder(), WUFFS_VERSION, 0) |
| .message()); |
| |
| if (g_flags.input_allow_comments) { |
| g_dec.set_quirk_enabled(WUFFS_JSON__QUIRK_ALLOW_COMMENT_BLOCK, true); |
| g_dec.set_quirk_enabled(WUFFS_JSON__QUIRK_ALLOW_COMMENT_LINE, true); |
| } |
| if (g_flags.input_allow_extra_comma) { |
| g_dec.set_quirk_enabled(WUFFS_JSON__QUIRK_ALLOW_EXTRA_COMMA, true); |
| } |
| if (g_flags.input_allow_inf_nan_numbers) { |
| g_dec.set_quirk_enabled(WUFFS_JSON__QUIRK_ALLOW_INF_NAN_NUMBERS, true); |
| } |
| |
| // Consume any optional trailing whitespace and comments. This isn't part of |
| // the JSON spec, but it works better with line oriented Unix tools (such as |
| // "echo 123 | jsonptr" where it's "echo", not "echo -n") or hand-edited JSON |
| // files which can accidentally contain trailing whitespace. |
| g_dec.set_quirk_enabled(WUFFS_JSON__QUIRK_ALLOW_TRAILING_FILLER, true); |
| |
| return nullptr; |
| } |
| |
| // ---- |
| |
| // ignore_return_value suppresses errors from -Wall -Werror. |
| static void // |
| ignore_return_value(int ignored) {} |
| |
| const char* // |
| read_src() { |
| if (g_src.meta.closed) { |
| return "main: internal error: read requested on a closed source"; |
| } |
| g_src.compact(); |
| if (g_src.meta.wi >= g_src.data.len) { |
| return "main: g_src buffer is full"; |
| } |
| while (true) { |
| ssize_t n = read(g_input_file_descriptor, g_src.writer_pointer(), |
| g_src.writer_length()); |
| if (n >= 0) { |
| g_src.meta.wi += n; |
| g_src.meta.closed = n == 0; |
| break; |
| } else if (errno != EINTR) { |
| return strerror(errno); |
| } |
| } |
| return nullptr; |
| } |
| |
| const char* // |
| flush_dst() { |
| while (true) { |
| size_t n = g_dst.reader_length(); |
| if (n == 0) { |
| break; |
| } |
| const int stdout_fd = 1; |
| ssize_t i = write(stdout_fd, g_dst.reader_pointer(), n); |
| if (i >= 0) { |
| g_dst.meta.ri += i; |
| } else if (errno != EINTR) { |
| return strerror(errno); |
| } |
| } |
| g_dst.compact(); |
| return nullptr; |
| } |
| |
| const char* // |
| write_dst_slow(const void* s, size_t n) { |
| const uint8_t* p = static_cast<const uint8_t*>(s); |
| while (n > 0) { |
| size_t i = g_dst.writer_length(); |
| if (i == 0) { |
| const char* z = flush_dst(); |
| if (z) { |
| return z; |
| } |
| i = g_dst.writer_length(); |
| if (i == 0) { |
| return "main: g_dst buffer is full"; |
| } |
| } |
| |
| if (i > n) { |
| i = n; |
| } |
| memcpy(g_dst.data.ptr + g_dst.meta.wi, p, i); |
| g_dst.meta.wi += i; |
| p += i; |
| n -= i; |
| g_wrote_to_dst = true; |
| } |
| return nullptr; |
| } |
| |
| inline const char* // |
| write_dst(const void* s, size_t n) { |
| if (g_suppress_write_dst > 0) { |
| return nullptr; |
| } else if (n <= (DST_BUFFER_ARRAY_SIZE - g_dst.meta.wi)) { |
| memcpy(g_dst.data.ptr + g_dst.meta.wi, s, n); |
| g_dst.meta.wi += n; |
| g_wrote_to_dst = true; |
| return nullptr; |
| } |
| return write_dst_slow(s, n); |
| } |
| |
| #define TRY_INDENT_WITH_LEADING_NEW_LINE \ |
| do { \ |
| uint32_t adj = (g_num_input_blank_lines > 1) ? 1 : 0; \ |
| g_num_input_blank_lines = 0; \ |
| uint32_t indent = g_depth * g_bytes_per_indent_depth; \ |
| TRY(write_dst(g_two_new_lines_then_256_indent_bytes + 1 - adj, \ |
| 1 + adj + (indent & 0xFF))); \ |
| for (indent >>= 8; indent > 0; indent--) { \ |
| TRY(write_dst(g_two_new_lines_then_256_indent_bytes + 2, 0x100)); \ |
| } \ |
| } while (false) |
| |
| // TRY_INDENT_SANS_LEADING_NEW_LINE is used after comments, which print their |
| // own "\n". |
| #define TRY_INDENT_SANS_LEADING_NEW_LINE \ |
| do { \ |
| uint32_t adj = (g_num_input_blank_lines > 1) ? 1 : 0; \ |
| g_num_input_blank_lines = 0; \ |
| uint32_t indent = g_depth * g_bytes_per_indent_depth; \ |
| TRY(write_dst(g_two_new_lines_then_256_indent_bytes + 2 - adj, \ |
| adj + (indent & 0xFF))); \ |
| for (indent >>= 8; indent > 0; indent--) { \ |
| TRY(write_dst(g_two_new_lines_then_256_indent_bytes + 2, 0x100)); \ |
| } \ |
| } while (false) |
| |
| // ---- |
| |
| const char* // |
| handle_unicode_code_point(uint32_t ucp) { |
| if (ucp < 0x80) { |
| return write_dst(&ascii_escapes[8 * ucp + 1], ascii_escapes[8 * ucp]); |
| } |
| uint8_t u[WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL]; |
| size_t n = wuffs_base__utf_8__encode( |
| wuffs_base__make_slice_u8(&u[0], |
| WUFFS_BASE__UTF_8__BYTE_LENGTH__MAX_INCL), |
| ucp); |
| if (n == 0) { |
| return "main: internal error: unexpected Unicode code point"; |
| } |
| return write_dst(&u[0], n); |
| } |
| |
| // ---- |
| |
| inline const char* // |
| handle_token(wuffs_base__token t, bool start_of_token_chain) { |
| do { |
| int64_t vbc = t.value_base_category(); |
| uint64_t vbd = t.value_base_detail(); |
| uint64_t token_length = t.length(); |
| // The "- token_length" is because we incremented g_cursor_index before |
| // calling handle_token. |
| wuffs_base__slice_u8 tok = wuffs_base__make_slice_u8( |
| g_src.data.ptr + g_cursor_index - token_length, token_length); |
| |
| // Handle ']' or '}'. |
| if ((vbc == WUFFS_BASE__TOKEN__VBC__STRUCTURE) && |
| (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__POP)) { |
| if (g_query.is_at(g_depth)) { |
| return "main: no match for query"; |
| } |
| if (g_depth <= 0) { |
| return "main: internal error: inconsistent g_depth"; |
| } |
| g_depth--; |
| |
| if (g_query.matched_all() && (g_depth >= g_flags.max_output_depth)) { |
| g_suppress_write_dst--; |
| // '…' is U+2026 HORIZONTAL ELLIPSIS, which is 3 UTF-8 bytes. |
| TRY(write_dst((vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_LIST) |
| ? "\"[…]\"" |
| : "\"{…}\"", |
| 7)); |
| } else { |
| // Write preceding whitespace. |
| if ((g_ctx != context::in_list_after_bracket) && |
| (g_ctx != context::in_dict_after_brace) && |
| !g_flags.compact_output) { |
| if (g_is_after_comment) { |
| TRY_INDENT_SANS_LEADING_NEW_LINE; |
| } else { |
| if (g_flags.output_extra_comma) { |
| TRY(write_dst(",", 1)); |
| } |
| TRY_INDENT_WITH_LEADING_NEW_LINE; |
| } |
| } else { |
| g_num_input_blank_lines = 0; |
| } |
| |
| TRY(write_dst( |
| (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__FROM_LIST) ? "]" : "}", |
| 1)); |
| } |
| |
| g_ctx = (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST) |
| ? context::in_list_after_value |
| : context::in_dict_after_key; |
| goto after_value; |
| } |
| |
| // Write preceding whitespace and punctuation, if it wasn't ']', '}' or a |
| // continuation of a multi-token chain. |
| if (start_of_token_chain) { |
| if (g_is_after_comment) { |
| TRY_INDENT_SANS_LEADING_NEW_LINE; |
| } else if (g_ctx == context::in_dict_after_key) { |
| TRY(write_dst(": ", g_flags.compact_output ? 1 : 2)); |
| } else if (g_ctx != context::none) { |
| if ((g_ctx != context::in_list_after_bracket) && |
| (g_ctx != context::in_dict_after_brace)) { |
| TRY(write_dst(",", 1)); |
| } |
| if (!g_flags.compact_output) { |
| TRY_INDENT_WITH_LEADING_NEW_LINE; |
| } |
| } |
| |
| bool query_matched_fragment = false; |
| if (g_query.is_at(g_depth)) { |
| switch (g_ctx) { |
| case context::in_list_after_bracket: |
| case context::in_list_after_value: |
| query_matched_fragment = g_query.tick(); |
| break; |
| case context::in_dict_after_key: |
| query_matched_fragment = g_query.matched_fragment(); |
| break; |
| default: |
| break; |
| } |
| } |
| if (!query_matched_fragment) { |
| // No-op. |
| } else if (!g_query.next_fragment()) { |
| // There is no next fragment. We have matched the complete query, and |
| // the upcoming JSON value is the result of that query. |
| // |
| // Un-suppress writing to stdout and reset the g_ctx and g_depth as if |
| // we were about to decode a top-level value. This makes any subsequent |
| // indentation be relative to this point, and we will return g_eod |
| // after the upcoming JSON value is complete. |
| if (g_suppress_write_dst != 1) { |
| return "main: internal error: inconsistent g_suppress_write_dst"; |
| } |
| g_suppress_write_dst = 0; |
| g_ctx = context::none; |
| g_depth = 0; |
| } else if ((vbc != WUFFS_BASE__TOKEN__VBC__STRUCTURE) || |
| !(vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__PUSH)) { |
| // The query has moved on to the next fragment but the upcoming JSON |
| // value is not a container. |
| return "main: no match for query"; |
| } |
| } |
| |
| // Handle the token itself: either a container ('[' or '{') or a simple |
| // value: string (a chain of raw or escaped parts), literal or number. |
| switch (vbc) { |
| case WUFFS_BASE__TOKEN__VBC__STRUCTURE: |
| if (g_query.matched_all() && (g_depth >= g_flags.max_output_depth)) { |
| g_suppress_write_dst++; |
| } else { |
| TRY(write_dst( |
| (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST) ? "[" : "{", |
| 1)); |
| } |
| g_depth++; |
| g_ctx = (vbd & WUFFS_BASE__TOKEN__VBD__STRUCTURE__TO_LIST) |
| ? context::in_list_after_bracket |
| : context::in_dict_after_brace; |
| g_num_input_blank_lines = 0; |
| return nullptr; |
| |
| case WUFFS_BASE__TOKEN__VBC__STRING: |
| if (start_of_token_chain) { |
| TRY(write_dst("\"", 1)); |
| g_query.restart_fragment(in_dict_before_key() && |
| g_query.is_at(g_depth)); |
| } |
| |
| if (vbd & WUFFS_BASE__TOKEN__VBD__STRING__CONVERT_1_DST_1_SRC_COPY) { |
| TRY(write_dst(tok.ptr, tok.len)); |
| g_query.incremental_match_slice(tok.ptr, tok.len); |
| } |
| |
| if (t.continued()) { |
| return nullptr; |
| } |
| TRY(write_dst("\"", 1)); |
| goto after_value; |
| |
| case WUFFS_BASE__TOKEN__VBC__UNICODE_CODE_POINT: |
| if (!t.continued()) { |
| return "main: internal error: unexpected non-continued UCP token"; |
| } |
| TRY(handle_unicode_code_point(vbd)); |
| g_query.incremental_match_code_point(vbd); |
| return nullptr; |
| } |
| |
| // We have a literal or a number. |
| TRY(write_dst(tok.ptr, tok.len)); |
| goto after_value; |
| } while (0); |
| |
| // Book-keeping after completing a value (whether a container value or a |
| // simple value). Empty parent containers are no longer empty. If the parent |
| // container is a "{...}" object, toggle between keys and values. |
| after_value: |
| if (g_depth == 0) { |
| return g_eod; |
| } |
| switch (g_ctx) { |
| case context::in_list_after_bracket: |
| g_ctx = context::in_list_after_value; |
| break; |
| case context::in_dict_after_brace: |
| g_ctx = context::in_dict_after_key; |
| break; |
| case context::in_dict_after_key: |
| g_ctx = context::in_dict_after_value; |
| break; |
| case context::in_dict_after_value: |
| g_ctx = context::in_dict_after_key; |
| break; |
| default: |
| break; |
| } |
| return nullptr; |
| } |
| |
| const char* // |
| main1(int argc, char** argv) { |
| TRY(initialize_globals(argc, argv)); |
| |
| bool start_of_token_chain = true; |
| while (true) { |
| wuffs_base__status status = g_dec.decode_tokens( |
| &g_tok, &g_src, |
| wuffs_base__make_slice_u8(g_work_buffer_array, WORK_BUFFER_ARRAY_SIZE)); |
| |
| while (g_tok.meta.ri < g_tok.meta.wi) { |
| wuffs_base__token t = g_tok.data.ptr[g_tok.meta.ri++]; |
| uint64_t token_length = t.length(); |
| if ((g_src.meta.ri - g_cursor_index) < token_length) { |
| return "main: internal error: inconsistent g_src indexes"; |
| } |
| g_cursor_index += token_length; |
| |
| // Handle filler tokens (e.g. whitespace, punctuation and comments). |
| // These are skipped, unless -output-comments is enabled. |
| if (t.value_base_category() == WUFFS_BASE__TOKEN__VBC__FILLER) { |
| if (!g_flags.output_comments) { |
| // No-op. |
| } else if (t.value_base_detail() & |
| WUFFS_BASE__TOKEN__VBD__FILLER__COMMENT_ANY) { |
| if (g_flags.compact_output) { |
| TRY(write_dst(g_src.data.ptr + g_cursor_index - token_length, |
| token_length)); |
| |
| } else { |
| if (start_of_token_chain) { |
| if (g_is_after_comment) { |
| TRY_INDENT_SANS_LEADING_NEW_LINE; |
| } else if (g_ctx != context::none) { |
| if (g_ctx == context::in_dict_after_key) { |
| TRY(write_dst(":", 1)); |
| } else if ((g_ctx != context::in_list_after_bracket) && |
| (g_ctx != context::in_dict_after_brace) && |
| (g_ctx != context::end_of_data)) { |
| TRY(write_dst(",", 1)); |
| } |
| TRY_INDENT_WITH_LEADING_NEW_LINE; |
| } |
| } |
| TRY(write_dst(g_src.data.ptr + g_cursor_index - token_length, |
| token_length)); |
| if (!t.continued() && |
| (t.value_base_detail() & |
| WUFFS_BASE__TOKEN__VBD__FILLER__COMMENT_BLOCK)) { |
| TRY(write_dst("\n", 1)); |
| } |
| g_is_after_comment = true; |
| } |
| if (g_ctx == context::in_list_after_bracket) { |
| g_ctx = context::in_list_after_value; |
| } else if (g_ctx == context::in_dict_after_brace) { |
| g_ctx = context::in_dict_after_value; |
| } |
| g_num_input_blank_lines = |
| (t.value_base_detail() & |
| WUFFS_BASE__TOKEN__VBD__FILLER__COMMENT_LINE) |
| ? 1 |
| : 0; |
| |
| } else { |
| uint8_t* p = g_src.data.ptr + g_cursor_index - token_length; |
| uint8_t* q = g_src.data.ptr + g_cursor_index; |
| for (; p < q; p++) { |
| if (*p == '\n') { |
| g_num_input_blank_lines++; |
| } |
| } |
| } |
| |
| start_of_token_chain = !t.continued(); |
| continue; |
| } |
| |
| const char* z = handle_token(t, start_of_token_chain); |
| g_is_after_comment = false; |
| start_of_token_chain = !t.continued(); |
| if (z == nullptr) { |
| continue; |
| } else if (z != g_eod) { |
| return z; |
| } else if (g_flags.query_c_string && *g_flags.query_c_string) { |
| // With a non-empty g_query, don't try to consume trailing filler or |
| // confirm that we've processed all the tokens. |
| return nullptr; |
| } |
| g_ctx = context::end_of_data; |
| } |
| |
| if (status.repr == nullptr) { |
| if (g_ctx != context::end_of_data) { |
| return "main: internal error: unexpected end of token stream"; |
| } |
| // Check that we've exhausted the input. |
| if ((g_src.meta.ri == g_src.meta.wi) && !g_src.meta.closed) { |
| TRY(read_src()); |
| } |
| if ((g_src.meta.ri < g_src.meta.wi) || !g_src.meta.closed) { |
| return "main: valid JSON followed by further (unexpected) data"; |
| } |
| // All done. |
| return nullptr; |
| } else if (status.repr == wuffs_base__suspension__short_read) { |
| if (g_cursor_index != g_src.meta.ri) { |
| return "main: internal error: inconsistent g_src indexes"; |
| } |
| TRY(read_src()); |
| g_cursor_index = g_src.meta.ri; |
| } else if (status.repr == wuffs_base__suspension__short_write) { |
| g_tok.compact(); |
| } else { |
| return status.message(); |
| } |
| } |
| } |
| |
| int // |
| compute_exit_code(const char* status_msg) { |
| if (!status_msg) { |
| return 0; |
| } |
| size_t n; |
| if (status_msg == g_usage) { |
| n = strlen(status_msg); |
| } else { |
| n = strnlen(status_msg, 2047); |
| if (n >= 2047) { |
| status_msg = "main: internal error: error message is too long"; |
| n = strnlen(status_msg, 2047); |
| } |
| } |
| const int stderr_fd = 2; |
| ignore_return_value(write(stderr_fd, status_msg, n)); |
| ignore_return_value(write(stderr_fd, "\n", 1)); |
| // Return an exit code of 1 for regular (foreseen) errors, e.g. badly |
| // formatted or unsupported input. |
| // |
| // Return an exit code of 2 for internal (exceptional) errors, e.g. defensive |
| // run-time checks found that an internal invariant did not hold. |
| // |
| // Automated testing, including badly formatted inputs, can therefore |
| // discriminate between expected failure (exit code 1) and unexpected failure |
| // (other non-zero exit codes). Specifically, exit code 2 for internal |
| // invariant violation, exit code 139 (which is 128 + SIGSEGV on x86_64 |
| // linux) for a segmentation fault (e.g. null pointer dereference). |
| return strstr(status_msg, "internal error:") ? 2 : 1; |
| } |
| |
| int // |
| main(int argc, char** argv) { |
| // Look for an input filename (the first non-flag argument) in argv. If there |
| // is one, open it (but do not read from it) before we self-impose a sandbox. |
| // |
| // Flags start with "-", unless it comes after a bare "--" arg. |
| { |
| bool dash_dash = false; |
| int a; |
| for (a = 1; a < argc; a++) { |
| char* arg = argv[a]; |
| if ((arg[0] == '-') && !dash_dash) { |
| dash_dash = (arg[1] == '-') && (arg[2] == '\x00'); |
| continue; |
| } |
| g_input_file_descriptor = open(arg, O_RDONLY); |
| if (g_input_file_descriptor < 0) { |
| fprintf(stderr, "%s: %s\n", arg, strerror(errno)); |
| return 1; |
| } |
| break; |
| } |
| } |
| |
| #if defined(WUFFS_EXAMPLE_USE_SECCOMP) |
| prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT); |
| g_sandboxed = true; |
| #endif |
| |
| const char* z = main1(argc, argv); |
| if (g_wrote_to_dst) { |
| const char* z1 = g_is_after_comment ? nullptr : write_dst("\n", 1); |
| const char* z2 = flush_dst(); |
| z = z ? z : (z1 ? z1 : z2); |
| } |
| int exit_code = compute_exit_code(z); |
| |
| #if defined(WUFFS_EXAMPLE_USE_SECCOMP) |
| // Call SYS_exit explicitly, instead of calling SYS_exit_group implicitly by |
| // either calling _exit or returning from main. SECCOMP_MODE_STRICT allows |
| // only SYS_exit. |
| syscall(SYS_exit, exit_code); |
| #endif |
| return exit_code; |
| } |
