@ 261102.1

261008.3 · e001deb4cfb735a6b14a802398a41bfa03df5a2a

Strip UTF-8 BOM at the start of each input file (#3657)

The UTF-8 BOM was stripped only at the start of the parser stream, but jq feeds all input files into a single parser, so a BOM at the start of the second and later files reached the parser as content and failed with a confusing "Invalid numeric literal" error. Strip it in the file readers instead, at the start of each input file including stdin, and in jv_load_file.

This also strips the BOM for raw input, so -R and --rawfile no longer yield a leading U+FEFF, and a BOM at the start of a -f program file or an imported module is now accepted rather than reported as a syntax error. In exchange, "\uFEFF1" | fromjson is now a parse error, since a U+FEFF inside a string is content rather than an encoding marker, and the dedicated "Malformed BOM" error is gone.

reading declarations

src/jv_file.c

@@ -43,6 +43,7 @@ jv jv_load_file(const char* filename, int raw) {   // buffer, we need to be able to read the remainder of a sequence and add that   // before appending.   char buf[4096 + 4];+  int at_file_start = 1;   while (!feof(file) && !ferror(file)) {     size_t n = fread(buf, 1, sizeof(buf) - 4, file);     if (n == 0)@@ -55,12 +56,22 @@ jv jv_load_file(const char* filename, int raw) {       n += fread(end, 1, len, file);     } +    char *p = buf;+    if (at_file_start) {+      // Strip UTF-8 BOM at the start of the file+      if (n >= 3 && !memcmp(buf, "\xEF\xBB\xBF", 3)) {+        p += 3;+        n -= 3;+      }+      at_file_start = 0;+    }+     if (raw) {-      data = jv_string_append_buf(data, buf, n);+      data = jv_string_append_buf(data, p, n);       if (!jv_is_valid(data))         break;     } else {-      jv_parser_set_buf(parser, buf, n, !feof(file));+      jv_parser_set_buf(parser, p, n, !feof(file));       jv value;       while (jv_is_valid((value = jv_parser_next(parser))))         data = jv_array_append(data, value);

src/jv_parse.c

@@ -37,7 +37,6 @@ struct jv_parser {   int curr_buf_pos;   int curr_buf_is_partial;   int eof;-  unsigned bom_strip_position;    int flags; @@ -90,7 +89,6 @@ static void parser_init(struct jv_parser* p, int flags) {   p->eof = 0;   p->curr_buf = 0;   p->curr_buf_length = p->curr_buf_pos = p->curr_buf_is_partial = 0;-  p->bom_strip_position = 0;   p->last_ch_was_ws = 0;   p->line = 1;   p->column = 0;@@ -729,8 +727,6 @@ void jv_parser_free(struct jv_parser* p) {   jv_mem_free(p); } -static const unsigned char UTF8_BOM[] = {0xEF,0xBB,0xBF};- int jv_parser_remaining(struct jv_parser* p) {   if (p->curr_buf == 0)     return 0;@@ -740,22 +736,6 @@ int jv_parser_remaining(struct jv_parser* p) { void jv_parser_set_buf(struct jv_parser* p, const char* buf, int length, int is_partial) {   assert((p->curr_buf == 0 || p->curr_buf_pos == p->curr_buf_length)          && "previous buffer not exhausted");-  while (length > 0 && p->bom_strip_position < sizeof(UTF8_BOM)) {-    if ((unsigned char)*buf == UTF8_BOM[p->bom_strip_position]) {-      // matched a BOM character-      buf++;-      length--;-      p->bom_strip_position++;-    } else {-      if (p->bom_strip_position == 0) {-        // no BOM in this document-        p->bom_strip_position = sizeof(UTF8_BOM);-      } else {-        // malformed BOM (prefix present, rest missing)-        p->bom_strip_position = 0xff;-      }-    }-  }   p->curr_buf = buf;   p->curr_buf_length = length;   p->curr_buf_pos = 0;@@ -779,12 +759,6 @@ jv jv_parser_next(struct jv_parser* p) {     return jv_invalid();   if (!p->curr_buf)     return jv_invalid(); // Need a buffer-  if (p->bom_strip_position == 0xff) {-    if (!(p->flags & JV_PARSE_SEQ))-      return jv_invalid_with_msg(jv_string("Malformed BOM"));-    p->st =JV_PARSER_WAITING_FOR_RS;-    parser_reset(p);-  }   jv value = jv_invalid();   if ((p->flags & JV_PARSE_STREAMING) && stream_check_done(p, &value))     return value;

src/util.c

@@ -193,6 +193,7 @@ struct jq_util_input_state {   size_t buf_valid_len;   jv current_filename;   size_t current_line;+  int at_file_start; };  static void fprinter(void *data, const char *fname) {@@ -277,6 +278,7 @@ static int jq_util_input_read_more(jq_util_input_state *state) {     if (f != NULL) {       jv_free(state->current_filename);       state->current_line = 0;+      state->at_file_start = 1;       if (!strcmp(f, "-")) {         state->current_input = stdin;         state->current_filename = jv_string("<stdin>");@@ -343,6 +345,14 @@ static int jq_util_input_read_more(jq_util_input_state *state) {         state->buf_valid_len = (p - state->buf) + 1;       }     }+    if (state->at_file_start) {+      // Strip UTF-8 BOM at the start of each file+      if (state->buf_valid_len >= 3 && !memcmp(state->buf, "\xEF\xBB\xBF", 3)) {+        state->buf_valid_len -= 3;+        memmove(state->buf, state->buf + 3, state->buf_valid_len);+      }+      state->at_file_start = 0;+    }   }   return state->curr_file == state->nfiles && !state->current_input; }

tests/jq.test

@@ -42,13 +42,6 @@ null {"x":-1} {"x":1} -# The input line starts with a 0xFEFF (byte order mark) codepoint-# No, there is no reason to have a byte order mark in UTF8 text.-# But apparently people do, so jq shouldn't break on it.-.-"byte order mark"-"byte order mark"- # We test escapes by matching them against Unicode codepoints # FIXME: more tests needed for weird unicode stuff (e.g. utf16 pairs) "Aa\r\n\t\b\f\u03bc"

tests/shtest

@@ -57,6 +57,17 @@ for exp in '1+1' '1-1' '2*3' '9/3' '9%3' '9==3' '9!=3' \   fi done +## Test UTF-8 BOM is stripped at the start of each input file+printf '\357\273\277[{"foo": 1}\n,{"foo": 2}\n]\n' > $d/bom1.json+printf '\357\273\277[{"foo": 3}\n,{"foo": 4}\n]\n' > $d/bom2.json+$VALGRIND $Q $JQ -e '.[0].foo == 1' $d/bom1.json+$VALGRIND $Q $JQ -se '. == [[{"foo":1},{"foo":2}],[{"foo":3},{"foo":4}]]' $d/bom1.json $d/bom2.json+$VALGRIND $Q $JQ -ne '[inputs] == [[{"foo":1},{"foo":2}],[{"foo":3},{"foo":4}]]' $d/bom1.json $d/bom2.json+$VALGRIND $Q $JQ -ne '[inputs] == [[{"foo":1},{"foo":2}],[{"foo":3},{"foo":4}]]' $d/bom1.json - < $d/bom2.json+$VALGRIND $Q $JQ -Rne '[inputs] == ["[{\"foo\": 1}", ",{\"foo\": 2}", "]", "[{\"foo\": 3}", ",{\"foo\": 4}", "]"]' $d/bom1.json $d/bom2.json+$VALGRIND $Q $JQ -ne --slurpfile x $d/bom1.json '$x == [[{"foo":1},{"foo":2}]]'+$VALGRIND $Q $JQ -ne --rawfile x $d/bom1.json '$x == "[{\"foo\": 1}\n,{\"foo\": 2}\n]\n"'+ ## Test JSON sequence support cat > $d/expected <<EOF jq: ignoring parse error: Truncated value at line 2, column 5