Lexer crash fix (#3900)

* input may return 0 for EOF

Stops overruns into fread from nothing.

* remove two trailing contexts

* fix up sgml tokens

Rakefile

@@ -47,15 +47,10 @@ task :samples => :compile do
   File.write 'lib/linguist/samples.json', json
 end
 
-FLEX_MIN_VER = [2, 5, 39]
 task :flex do
-  if `flex -V` !~ /^flex (\d+)\.(\d+)\.(\d+)/
+  if `flex -V` !~ /^flex \d+\.\d+\.\d+/
     fail "flex not detected"
   end
-  maj, min, rev = $1.to_i, $2.to_i, $3.to_i
-  if maj < FLEX_MIN_VER[0] || (maj == FLEX_MIN_VER[0] && (min < FLEX_MIN_VER[1] || (min == FLEX_MIN_VER[1] && rev < FLEX_MIN_VER[2])))
-    fail "building linguist's lexer requires at least flex #{FLEX_MIN_VER.join(".")}"
-  end
   system "cd ext/linguist && flex tokenizer.l"
 end
 

ext/linguist/lex.linguist_yy.h

@@ -11,7 +11,7 @@
 #define FLEX_SCANNER
 #define YY_FLEX_MAJOR_VERSION 2
 #define YY_FLEX_MINOR_VERSION 5
-#define YY_FLEX_SUBMINOR_VERSION 39
+#define YY_FLEX_SUBMINOR_VERSION 35
 #if YY_FLEX_SUBMINOR_VERSION > 0
 #define FLEX_BETA
 #endif
@@ -49,6 +49,7 @@ typedef int16_t flex_int16_t;
 typedef uint16_t flex_uint16_t;
 typedef int32_t flex_int32_t;
 typedef uint32_t flex_uint32_t;
+typedef uint64_t flex_uint64_t;
 #else
 typedef signed char flex_int8_t;
 typedef short int flex_int16_t;
@@ -56,6 +57,7 @@ typedef int flex_int32_t;
 typedef unsigned char flex_uint8_t; 
 typedef unsigned short int flex_uint16_t;
 typedef unsigned int flex_uint32_t;
+#endif /* ! C99 */
 
 /* Limits of integral types. */
 #ifndef INT8_MIN
@@ -86,8 +88,6 @@ typedef unsigned int flex_uint32_t;
 #define UINT32_MAX             (4294967295U)
 #endif
 
-#endif /* ! C99 */
-
 #endif /* ! FLEXINT_H */
 
 #ifdef __cplusplus
@@ -130,15 +130,7 @@ typedef void* yyscan_t;
 
 /* Size of default input buffer. */
 #ifndef YY_BUF_SIZE
-#ifdef __ia64__
-/* On IA-64, the buffer size is 16k, not 8k.
- * Moreover, YY_BUF_SIZE is 2*YY_READ_BUF_SIZE in the general case.
- * Ditto for the __ia64__ case accordingly.
- */
-#define YY_BUF_SIZE 32768
-#else
 #define YY_BUF_SIZE 16384
-#endif /* __ia64__ */
 #endif
 
 #ifndef YY_TYPEDEF_YY_BUFFER_STATE
@@ -277,10 +269,6 @@ int linguist_yyget_lineno (yyscan_t yyscanner );
 
 void linguist_yyset_lineno (int line_number ,yyscan_t yyscanner );
 
-int linguist_yyget_column  (yyscan_t yyscanner );
-
-void linguist_yyset_column (int column_no ,yyscan_t yyscanner );
-
 /* Macros after this point can all be overridden by user definitions in
  * section 1.
  */
@@ -307,12 +295,7 @@ static int yy_flex_strlen (yyconst char * ,yyscan_t yyscanner);
 
 /* Amount of stuff to slurp up with each read. */
 #ifndef YY_READ_BUF_SIZE
-#ifdef __ia64__
-/* On IA-64, the buffer size is 16k, not 8k */
-#define YY_READ_BUF_SIZE 16384
-#else
 #define YY_READ_BUF_SIZE 8192
-#endif /* __ia64__ */
 #endif
 
 /* Number of entries by which start-condition stack grows. */
@@ -345,9 +328,9 @@ extern int linguist_yylex (yyscan_t yyscanner);
 #undef YY_DECL
 #endif
 
-#line 117 "tokenizer.l"
+#line 118 "tokenizer.l"
 
 
-#line 352 "lex.linguist_yy.h"
+#line 335 "lex.linguist_yy.h"
 #undef linguist_yyIN_HEADER
 #endif /* linguist_yyHEADER_H */

ext/linguist/tokenizer.l

@@ -9,25 +9,25 @@
 
 #define eat_until_eol() do { \
     int c; \
-    while ((c = input(yyscanner)) != '\n' && c != EOF); \
-    if (c == EOF) \
-      yyterminate(); \
+    while ((c = input(yyscanner)) != '\n' && c != EOF && c); \
+    if (c == EOF || !c) \
+      return 0; \
   } while (0)
 
 #define eat_until_unescaped(q) do { \
     int c; \
-    while ((c = input(yyscanner)) != EOF) { \
+    while ((c = input(yyscanner)) != EOF && c) { \
       if (c == '\n') \
         break; \
       if (c == '\\') { \
         c = input(yyscanner); \
-        if (c == EOF) \
-          yyterminate(); \
+        if (c == EOF || !c) \
+          return 0; \
       } else if (c == q) \
         break; \
     } \
-    if (c == EOF) \
-      yyterminate(); \
+    if (c == EOF || !c) \
+      return 0; \
   } while (0)
 
 %}
@@ -84,7 +84,7 @@
 \"                                { eat_until_unescaped('"'); }
 '                                 { eat_until_unescaped('\''); }
 (0x[0-9a-fA-F]([0-9a-fA-F]|\.)*|[0-9]([0-9]|\.)*)([uU][lL]{0,2}|([eE][-+][0-9]*)?[fFlL]*) { /* nothing */ }
-\<[^ \t\n\r<>]+/>|" "[^<>\n]{0,2048}>               {
+\<[[:alnum:]_!./?-]+              {
     if (strcmp(yytext, "<!--") == 0) {
      BEGIN(xml_comment);
     } else {
@@ -93,8 +93,8 @@
       return 1;
     }
   }
-<sgml>[[:alnum:]_]+=/\"           { feed_token(strdup(yytext), REGULAR_TOKEN); input(yyscanner); eat_until_unescaped('"'); return 1; }
-<sgml>[[:alnum:]_]+=/'            { feed_token(strdup(yytext), REGULAR_TOKEN); input(yyscanner); eat_until_unescaped('\''); return 1; }
+<sgml>[[:alnum:]_]+=\"            { feed_token(strndup(yytext, strlen(yytext) - 1), REGULAR_TOKEN); eat_until_unescaped('"'); return 1; }
+<sgml>[[:alnum:]_]+='             { feed_token(strndup(yytext, strlen(yytext) - 1), REGULAR_TOKEN); eat_until_unescaped('\''); return 1; }
 <sgml>[[:alnum:]_]+=[[:alnum:]_]* { feed_token(strdup(yytext), REGULAR_TOKEN); *(strchr(yyextra->token, '=') + 1) = 0; return 1; }
 <sgml>[[:alnum:]_]+               { feed_token(strdup(yytext), REGULAR_TOKEN); return 1; }
 <sgml>\>                          { BEGIN(INITIAL); }