Use stack memory for buf

Also test on empty key files
richfitz · Jan 9, 2019 · 73fb923 · 73fb923
1 parent 474247f
commit 73fb923
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Showing 2 changed files with 19 additions and 6 deletions.
diff --git a/src/storr.c b/src/storr.c
@@ -3,19 +3,23 @@
 #include <Rinternals.h>
 #include <Rversion.h>
 
+#define MAX_HASH_LENGTH 128
+
 SEXP Cread_text_file(SEXP path, SEXP nchar) {
   FILE *fp;
   fp = fopen(CHAR(asChar(path)), "rb");
   if (fp == NULL) {
-    Rf_error("File %s does not exist", path);
+    Rf_error("File %s does not exist.", path);
   }
   int n = asInteger(nchar) + 1; // Need an extra character for '\0'.
-  char *buf = (char*) malloc(n * sizeof(char));
-  fgets(buf, n, fp);
+  char buf[MAX_HASH_LENGTH + 1];
+  char *res = fgets(buf, n, fp);
+  if (res == NULL) {
+    Rf_error("File %s is empty.", path);
+  }
   fclose(fp);
   SEXP out = PROTECT(mkString(buf));
   UNPROTECT(1);
-  free(buf);
   return out;
 }
 

diff --git a/tests/testthat/test-util.R b/tests/testthat/test-util.R
@@ -99,7 +99,16 @@ test_that("write_lines recovers on error", {
 
 test_that("read_text_file() works", {
   expect_false(file.exists("does_not_exist"))
-  expect_error(read_text_file("does_not_exist", 12))
+  expect_error(
+    read_text_file("does_not_exist", 12),
+    regexp = "does not exist"
+  )
+  file.create("empty_file")
+  on.exit(unlink("empty_file"))
+  expect_error(
+    read_text_file("empty_file", 12),
+    regexp = "is empty"
+  )
   randstring <- function(n) {
     paste(sample(letters, size = n, replace = TRUE), collapse = "")
   }
@@ -110,5 +119,5 @@ test_that("read_text_file() works", {
     on.exit(unlink(file))
     expect_equal(read_text_file(file, n), string)
   }
-  lapply(seq_len(200), test_read_text_file)
+    lapply(seq_len(127), test_read_text_file)
 })