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fix: protect SEXP objects in C code #728

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Merged
randy3k merged 1 commit into from
May 2, 2026
Merged

fix: protect SEXP objects in C code #728

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15 changes: 11 additions & 4 deletions src/reader.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,12 @@
#include "reader.h"

static SEXP safe_scalar_string(SEXP chr) {
PROTECT(chr);
SEXP res = Rf_ScalarString(chr);
UNPROTECT(1);
return res;
}


#if defined(_WIN32) || defined(_WIN64)

Expand Down Expand Up @@ -27,7 +34,7 @@ SEXP stdin_read_char(SEXP _n) {
if (bytes_avail > 0) {
ReadFile(h, buf, n, &bytes_read, NULL);
buf[bytes_read] = '\0';
return Rf_ScalarString(Rf_mkCharCE(buf, CE_UTF8));
return safe_scalar_string(Rf_mkCharCE(buf, CE_UTF8));
}
return Rf_allocVector(STRSXP, 0);
} else {
Expand Down Expand Up @@ -57,7 +64,7 @@ SEXP stdin_read_line(void) {
buf[bufpos - 1] = '\0';
}
bufpos = 0;
return Rf_ScalarString(Rf_mkCharCE(buf, CE_UTF8));
return safe_scalar_string(Rf_mkCharCE(buf, CE_UTF8));
}
bufpos++;
if (bufpos >= bufsize) {
Expand Down Expand Up @@ -101,7 +108,7 @@ SEXP stdin_read_char(SEXP _n) {

if (bytes_read > 0) {
buf[bytes_read] = '\0';
return Rf_ScalarString(Rf_mkCharCE(buf, CE_UTF8));
return safe_scalar_string(Rf_mkCharCE(buf, CE_UTF8));
} else {
return Rf_allocVector(STRSXP, 0);
}
Expand All @@ -122,7 +129,7 @@ SEXP stdin_read_line(void) {
buf[bufpos - 1] = '\0';
}
bufpos = 0;
return Rf_ScalarString(Rf_mkCharCE(buf, CE_UTF8));
return safe_scalar_string(Rf_mkCharCE(buf, CE_UTF8));
}
bufpos++;
if (bufpos >= bufsize) {
Expand Down
44 changes: 22 additions & 22 deletions src/token.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,9 +92,15 @@ static int is_token_start_cp(unsigned int cp) {

static SEXP make_str(const char *text, int start, int len) {
if (len <= 0) {
return Rf_mkString("");
SEXP chr = PROTECT(Rf_mkCharLenCE("", 0, CE_UTF8));
SEXP res = Rf_ScalarString(chr);
UNPROTECT(1);
return res;
}
return Rf_ScalarString(Rf_mkCharLenCE(text + start, len, CE_UTF8));
SEXP chr = PROTECT(Rf_mkCharLenCE(text + start, len, CE_UTF8));
SEXP res = Rf_ScalarString(chr);
UNPROTECT(1);
return res;
}

SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
Expand Down Expand Up @@ -136,11 +142,12 @@ SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
int right_len = right_end - right_start;
int end = do_forward ? right_end : right_start;

SEXP full_token = Rf_mkString("");
SEXP right_token = make_str(text, right_start, right_len);
SEXP package = Rf_mkString("");
SEXP accessor = Rf_mkString("");
SEXP token = Rf_mkString("");
SEXP out = PROTECT(Rf_allocVector(VECSXP, 5));
SET_VECTOR_ELT(out, 0, make_str("", 0, 0));
SET_VECTOR_ELT(out, 1, make_str(text, right_start, right_len));
SET_VECTOR_ELT(out, 2, make_str("", 0, 0));
SET_VECTOR_ELT(out, 3, make_str("", 0, 0));
SET_VECTOR_ELT(out, 4, make_str("", 0, 0));

if (right_len == 0) {
int acc_len = 0;
Expand Down Expand Up @@ -169,9 +176,9 @@ SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
int pkg_start = p + 1;
int pkg_len = pkg_end - pkg_start + 1;
if (pkg_len >= 2 && isalpha((unsigned char) text[pkg_start])) {
package = make_str(text, pkg_start, pkg_len);
accessor = make_str(text, acc_start, acc_len);
full_token = make_str(text, pkg_start, right_start - pkg_start);
SET_VECTOR_ELT(out, 2, make_str(text, pkg_start, pkg_len));
SET_VECTOR_ELT(out, 3, make_str(text, acc_start, acc_len));
SET_VECTOR_ELT(out, 0, make_str(text, pkg_start, right_start - pkg_start));
}
}
}
Expand Down Expand Up @@ -204,8 +211,8 @@ SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
if (is_token_start_cp(start_cp)) {
if (!(start > 0 && text[start - 1] == '$')) {
int token_len = end - start;
token = make_str(text, start, token_len);
full_token = token;
SET_VECTOR_ELT(out, 4, make_str(text, start, token_len));
SET_VECTOR_ELT(out, 0, VECTOR_ELT(out, 4));

if (start >= 2 && text[start - 1] == ':' && text[start - 2] == ':') {
int acc_len = 2;
Expand All @@ -232,9 +239,9 @@ SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
int pkg_len = pkg_end - pkg_start + 1;

if (pkg_len >= 2 && isalpha((unsigned char) text[pkg_start])) {
package = make_str(text, pkg_start, pkg_len);
accessor = make_str(text, acc_start, acc_len);
full_token = make_str(text, pkg_start, end - pkg_start);
SET_VECTOR_ELT(out, 2, make_str(text, pkg_start, pkg_len));
SET_VECTOR_ELT(out, 3, make_str(text, acc_start, acc_len));
SET_VECTOR_ELT(out, 0, make_str(text, pkg_start, end - pkg_start));
}
}
}
Expand All @@ -244,13 +251,6 @@ SEXP scan_token_c(SEXP line, SEXP col, SEXP forward) {
}
}

SEXP out = PROTECT(Rf_allocVector(VECSXP, 5));
SET_VECTOR_ELT(out, 0, full_token);
SET_VECTOR_ELT(out, 1, right_token);
SET_VECTOR_ELT(out, 2, package);
SET_VECTOR_ELT(out, 3, accessor);
SET_VECTOR_ELT(out, 4, token);

SEXP names = PROTECT(Rf_allocVector(STRSXP, 5));
SET_STRING_ELT(names, 0, Rf_mkChar("full_token"));
SET_STRING_ELT(names, 1, Rf_mkChar("right_token"));
Expand Down
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