json_parsert: construct with message handler

This both avoids an object of static lifetime as well as it fixes the
(transitive) use of the deprecated messaget() constructor. Both the
parser and lexer are now fully reentrant.

Author: tautschnig

src/json/json_parser.cpp

@@ -10,7 +10,18 @@ Author: Daniel Kroening, [email protected]
 
 #include <fstream>
 
-json_parsert json_parser;
+int yyjsonlex_init_extra(json_parsert *, void **);
+int yyjsonlex_destroy(void *);
+int yyjsonparse(json_parsert &, void *);
+
+bool json_parsert::parse()
+{
+  void *scanner;
+  yyjsonlex_init_extra(this, &scanner);
+  bool parse_fail = yyjsonparse(*this, scanner) != 0;
+  yyjsonlex_destroy(scanner);
+  return parse_fail;
+}
 
 // 'do it all' function
 bool parse_json(
@@ -19,10 +30,10 @@ bool parse_json(
   message_handlert &message_handler,
   jsont &dest)
 {
-  json_parser.clear();
+  json_parsert json_parser{message_handler};
+
   json_parser.set_file(filename);
   json_parser.in=&in;
-  json_parser.log.set_message_handler(message_handler);
 
   bool result=json_parser.parse();
 

src/json/json_parser.h

@@ -15,21 +15,20 @@ Author: Daniel Kroening, [email protected]
 #include <util/parser.h>
 #include <util/json.h>
 
-int yyjsonparse();
-void yyjsonrestart(FILE *input_file);
-
 class json_parsert:public parsert
 {
 public:
+  explicit json_parsert(message_handlert &message_handler)
+    : parsert(message_handler)
+  {
+  }
+
   typedef std::stack<jsont, std::vector<jsont> > stackt;
   stackt stack;
 
   jsont &top() { return stack.top(); }
 
-  virtual bool parse() override
-  {
-    return yyjsonparse()!=0;
-  }
+  bool parse() override;
 
   void push(const jsont &x)
   {
@@ -46,14 +45,9 @@ class json_parsert:public parsert
   virtual void clear() override
   {
     stack=stackt();
-    yyjsonrestart(nullptr);
   }
 };
 
-extern json_parsert json_parser;
-
-int yyjsonerror(const std::string &error);
-
 // 'do it all' functions
 bool parse_json(
   std::istream &in,

src/json/parser.y

@@ -20,11 +20,13 @@
 
 #include <util/unicode.h>
 
-int yyjsonlex();
-extern char *yyjsontext;
-extern int yyjsonleng; // really an int, not a size_t
+int yyjsonlex(void *);
+char *yyjsonget_text(void *);
+#define yyjsontext yyjsonget_text(scanner)
+int yyjsonget_leng(void *); // really an int, not a size_t
+#define yyjsonleng yyjsonget_leng(scanner)
 
-static std::string convert_TOK_STRING()
+static std::string convert_TOK_STRING(void *scanner)
 {
   PRECONDITION(yyjsontext[0]=='"');
   std::size_t len=yyjsonleng;
@@ -70,19 +72,23 @@ static std::string convert_TOK_STRING()
   return result;
 }
 
-static std::string convert_TOK_NUMBER()
+static std::string convert_TOK_NUMBER(void *scanner)
 {
   return yyjsontext;
 }
 
-int yyjsonerror(const std::string &error)
+int yyjsonerror(json_parsert &json_parser, void *scanner, const std::string &error)
 {
   json_parser.parse_error(error, yyjsontext);
   return 0;
 }
 
 %}
 
+%parse-param {json_parsert &json_parser}
+%parse-param {void *scanner}
+%lex-param {void *scanner}
+
 %token TOK_STRING
 %token TOK_NUMBER
 %token TOK_TRUE
@@ -109,7 +115,7 @@ key_value_pair:
           TOK_STRING
         {
           // we abuse the 'value' to temporarily store the key
-          json_parser.top().value=convert_TOK_STRING();
+          json_parser.top().value=convert_TOK_STRING(scanner);
         }
           ':' value
         {
@@ -139,9 +145,9 @@ array_value:
         ;
 
 value   : TOK_STRING
-        { json_parser.push(json_stringt(convert_TOK_STRING())); }
+        { json_parser.push(json_stringt(convert_TOK_STRING(scanner))); }
         | TOK_NUMBER
-        { json_parser.push(json_numbert(convert_TOK_NUMBER())); }
+        { json_parser.push(json_numbert(convert_TOK_NUMBER(scanner))); }
         | object
         | array
         | TOK_TRUE

src/json/scanner.l

@@ -11,8 +11,9 @@
 %option noinput
 %option nounistd
 %option never-interactive
-
 %option noyywrap
+%option reentrant
+%option extra-type="json_parsert *"
 
 %{
 
@@ -24,7 +25,7 @@
 #pragma warning(disable:4005)
 #endif
 
-#define PARSER json_parser
+#define PARSER (*yyextra)
 
 #include "json_parser.h"
 #include "json_y.tab.h"