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39
40#include "qscriptsyntaxchecker_p.h"
41
42#include "qscriptlexer_p.h"
43#include "qscriptparser_p.h"
44
45#include <stdlib.h>
46
47QT_BEGIN_NAMESPACE
48
49namespace QScript {
50
51
52SyntaxChecker::SyntaxChecker():
53 tos(0),
54 stack_size(0),
55 state_stack(0)
56{
57}
58
59SyntaxChecker::~SyntaxChecker()
60{
61 if (stack_size) {
62 free(ptr: state_stack);
63 }
64}
65
66bool SyntaxChecker::automatic(QScript::Lexer *lexer, int token) const
67{
68 return token == T_RBRACE || token == 0 || lexer->prevTerminator();
69}
70
71SyntaxChecker::Result SyntaxChecker::checkSyntax(const QString &code)
72{
73 const int INITIAL_STATE = 0;
74 QScript::Lexer lexer (/*engine=*/ 0);
75 lexer.setCode(c: code, /*lineNo*/ lineno: 1);
76
77 int yytoken = -1;
78 int saved_yytoken = -1;
79 QString error_message;
80 int error_lineno = -1;
81 int error_column = -1;
82 State checkerState = Valid;
83
84 reallocateStack();
85
86 tos = 0;
87 state_stack[++tos] = INITIAL_STATE;
88
89 while (true)
90 {
91 const int state = state_stack [tos];
92 if (yytoken == -1 && - TERMINAL_COUNT != action_index [state])
93 {
94 if (saved_yytoken == -1)
95 yytoken = lexer.lex();
96 else
97 {
98 yytoken = saved_yytoken;
99 saved_yytoken = -1;
100 }
101 }
102
103 int act = t_action (state, token: yytoken);
104
105 if (act == ACCEPT_STATE) {
106 if (lexer.error() == QScript::Lexer::UnclosedComment)
107 checkerState = Intermediate;
108 else
109 checkerState = Valid;
110 break;
111 } else if (act > 0) {
112 if (++tos == stack_size)
113 reallocateStack();
114
115 state_stack [tos] = act;
116 yytoken = -1;
117 }
118
119 else if (act < 0)
120 {
121 int r = - act - 1;
122
123 tos -= rhs [r];
124 act = state_stack [tos++];
125
126 if ((r == Q_SCRIPT_REGEXPLITERAL_RULE1)
127 || (r == Q_SCRIPT_REGEXPLITERAL_RULE2)) {
128 // Skip the rest of the RegExp literal
129 bool rx = lexer.scanRegExp();
130 if (!rx) {
131 checkerState = Intermediate;
132 break;
133 }
134 }
135
136 state_stack [tos] = nt_action (state: act, nt: lhs [r] - TERMINAL_COUNT);
137 }
138
139 else
140 {
141 if (saved_yytoken == -1 && automatic (lexer: &lexer, token: yytoken) && t_action (state, token: T_AUTOMATIC_SEMICOLON) > 0)
142 {
143 saved_yytoken = yytoken;
144 yytoken = T_SEMICOLON;
145 continue;
146 }
147
148 else if ((state == INITIAL_STATE) && (yytoken == 0)) {
149 // accept empty input
150 yytoken = T_SEMICOLON;
151 continue;
152 }
153
154 int ers = state;
155 int shifts = 0;
156 int reduces = 0;
157 int expected_tokens [3];
158 for (int tk = 0; tk < TERMINAL_COUNT; ++tk)
159 {
160 int k = t_action (state: ers, token: tk);
161
162 if (! k)
163 continue;
164 else if (k < 0)
165 ++reduces;
166 else if (spell [tk])
167 {
168 if (shifts < 3)
169 expected_tokens [shifts] = tk;
170 ++shifts;
171 }
172 }
173
174 error_message.clear ();
175 if (shifts && shifts < 3)
176 {
177 bool first = true;
178
179 for (int s = 0; s < shifts; ++s)
180 {
181 if (first)
182 error_message += QLatin1String ("Expected ");
183 else
184 error_message += QLatin1String (", ");
185
186 first = false;
187 error_message += QLatin1Char('`');
188 error_message += QLatin1String (spell [expected_tokens [s]]);
189 error_message += QLatin1Char('\'');
190 }
191 }
192
193 if (error_message.isEmpty())
194 error_message = lexer.errorMessage();
195
196 error_lineno = lexer.startLineNo();
197 error_column = lexer.startColumnNo();
198 checkerState = Error;
199 break;
200 }
201 }
202
203 if (checkerState == Error) {
204 if (lexer.error() == QScript::Lexer::UnclosedComment)
205 checkerState = Intermediate;
206 else if (yytoken == 0)
207 checkerState = Intermediate;
208 }
209 return Result(checkerState, error_lineno, error_column, error_message);
210}
211
212} // namespace QScript
213
214QT_END_NAMESPACE
215

source code of qtscript/src/script/parser/qscriptsyntaxchecker.cpp