summaryrefslogtreecommitdiffstats
path: root/src/script/qscriptsyntaxchecker.cpp
blob: 74ca00fb4f24651de125d9471e9944bcc5d30ef8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the QtScript module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qscriptsyntaxchecker_p.h"

#ifndef QT_NO_SCRIPT

#include "qscriptlexer_p.h"
#include "qscriptparser_p.h"

QT_BEGIN_NAMESPACE

namespace QScript {


SyntaxChecker::SyntaxChecker():
    tos(0),
    stack_size(0),
    state_stack(0)
{
}

SyntaxChecker::~SyntaxChecker()
{
    if (stack_size) {
        qFree(state_stack);
    }
}

bool SyntaxChecker::automatic(QScript::Lexer *lexer, int token) const
{
    return token == T_RBRACE || token == 0 || lexer->prevTerminator();
}

SyntaxChecker::Result SyntaxChecker::checkSyntax(const QString &code)
{
  const int INITIAL_STATE = 0;
  QScript::Lexer lexer (/*engine=*/ 0);
  lexer.setCode(code, /*lineNo*/ 1);

  int yytoken = -1;
  int saved_yytoken = -1;
  QString error_message;
  int error_lineno = -1;
  int error_column = -1;
  State checkerState = Valid;

  reallocateStack();

  tos = 0;
  state_stack[++tos] = INITIAL_STATE;

  while (true)
    {
      const int state = state_stack [tos];
      if (yytoken == -1 && - TERMINAL_COUNT != action_index [state])
        {
          if (saved_yytoken == -1)
            yytoken = lexer.lex();
          else
            {
              yytoken = saved_yytoken;
              saved_yytoken = -1;
            }
        }

      int act = t_action (state, yytoken);

      if (act == ACCEPT_STATE) {
          if (lexer.error() == QScript::Lexer::UnclosedComment)
              checkerState = Intermediate;
          else
              checkerState = Valid;
          break;
      } else if (act > 0) {
          if (++tos == stack_size)
            reallocateStack();

          state_stack [tos] = act;
          yytoken = -1;
        }

      else if (act < 0)
        {
          int r = - act - 1;

          tos -= rhs [r];
          act = state_stack [tos++];

          if ((r == Q_SCRIPT_REGEXPLITERAL_RULE1)
              || (r == Q_SCRIPT_REGEXPLITERAL_RULE2)) {
              // Skip the rest of the RegExp literal
              bool rx = lexer.scanRegExp();
              if (!rx) {
                  checkerState = Intermediate;
                  break;
              }
          }

          state_stack [tos] = nt_action (act, lhs [r] - TERMINAL_COUNT);
        }

      else
        {
          if (saved_yytoken == -1 && automatic (&lexer, yytoken) && t_action (state, T_AUTOMATIC_SEMICOLON) > 0)
            {
              saved_yytoken = yytoken;
              yytoken = T_SEMICOLON;
              continue;
            }

          else if ((state == INITIAL_STATE) && (yytoken == 0)) {
              // accept empty input
              yytoken = T_SEMICOLON;
              continue;
          }

          int ers = state;
          int shifts = 0;
          int reduces = 0;
          int expected_tokens [3];
          for (int tk = 0; tk < TERMINAL_COUNT; ++tk)
            {
              int k = t_action (ers, tk);

              if (! k)
                continue;
              else if (k < 0)
                ++reduces;
              else if (spell [tk])
                {
                  if (shifts < 3)
                    expected_tokens [shifts] = tk;
                  ++shifts;
                }
            }

          error_message.clear ();
          if (shifts && shifts < 3)
            {
              bool first = true;

              for (int s = 0; s < shifts; ++s)
                {
                  if (first)
                    error_message += QLatin1String ("Expected ");
                  else
                    error_message += QLatin1String (", ");

                  first = false;
                  error_message += QLatin1Char('`');
                  error_message += QLatin1String (spell [expected_tokens [s]]);
                  error_message += QLatin1Char('\'');
                }
            }

          if (error_message.isEmpty())
              error_message = lexer.errorMessage();

          error_lineno = lexer.startLineNo();
          error_column = lexer.startColumnNo();
          checkerState = Error;
          break;
        }
    }

  if (checkerState == Error) {
      if (lexer.error() == QScript::Lexer::UnclosedComment)
          checkerState = Intermediate;
      else if (yytoken == 0)
          checkerState = Intermediate;
  }
  return Result(checkerState, error_lineno, error_column, error_message);
}

} // namespace QScript

QT_END_NAMESPACE

#endif // QT_NO_SCRIPT