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Avoid use-after-free of external token states

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Previously, it was possible for references to external token states to
outlive the trees to which those states belonged.

Now, instead of storing references to external token states in the Stack
and in the Lexer, we store references to the external token trees
themselves, and we retain the trees to prevent use-after-free.
This commit is contained in:
Max Brunsfeld 2017-06-27 14:30:46 -07:00
parent f678018d3d
commit 0143bfdad4
11 changed files with 147 additions and 118 deletions
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10
src/runtime/lexer.c
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@ -110,7 +110,7 @@ void ts_lexer_init(Lexer *self) {
.payload = NULL,
.log = NULL
},
.last_external_token_state = NULL,
.last_external_token = NULL,
};
ts_lexer_reset(self, length_zero());
}
@ -134,7 +134,7 @@ static inline void ts_lexer__reset(Lexer *self, Length position) {
void ts_lexer_set_input(Lexer *self, TSInput input) {
self->input = input;
ts_lexer__reset(self, length_zero());
self->last_external_token_state = NULL;
ts_lexer_set_last_external_token(self, NULL);
}
void ts_lexer_reset(Lexer *self, Length position) {
@ -157,3 +157,9 @@ void ts_lexer_start(Lexer *self) {
void ts_lexer_advance_to_end(Lexer *self) {
while (self->data.lookahead != 0) ts_lexer__advance(self, false);
}
void ts_lexer_set_last_external_token(Lexer *self, Tree *token) {
if (token) ts_tree_retain(token);
if (self->last_external_token) ts_tree_release(self->last_external_token);
self->last_external_token = token;
}