2 files changed, 73 insertions, 7 deletions

diff --git a/compat/qsort_s.c b/compat/qsort_s.c
new file mode 100644
index 0000000000..52d1f0a73d
--- /dev/null
+++ b/compat/qsort_s.c
@@ -0,0 +1,69 @@
+#include "../git-compat-util.h"
+
+/*
+ * A merge sort implementation, simplified from the qsort implementation
+ * by Mike Haertel, which is a part of the GNU C Library.
+ * Added context pointer, safety checks and return value.
+ */
+
+static void msort_with_tmp(void *b, size_t n, size_t s,
+			   int (*cmp)(const void *, const void *, void *),
+			   char *t, void *ctx)
+{
+	char *tmp;
+	char *b1, *b2;
+	size_t n1, n2;
+
+	if (n <= 1)
+		return;
+
+	n1 = n / 2;
+	n2 = n - n1;
+	b1 = b;
+	b2 = (char *)b + (n1 * s);
+
+	msort_with_tmp(b1, n1, s, cmp, t, ctx);
+	msort_with_tmp(b2, n2, s, cmp, t, ctx);
+
+	tmp = t;
+
+	while (n1 > 0 && n2 > 0) {
+		if (cmp(b1, b2, ctx) <= 0) {
+			memcpy(tmp, b1, s);
+			tmp += s;
+			b1 += s;
+			--n1;
+		} else {
+			memcpy(tmp, b2, s);
+			tmp += s;
+			b2 += s;
+			--n2;
+		}
+	}
+	if (n1 > 0)
+		memcpy(tmp, b1, n1 * s);
+	memcpy(b, t, (n - n2) * s);
+}
+
+int git_qsort_s(void *b, size_t n, size_t s,
+		int (*cmp)(const void *, const void *, void *), void *ctx)
+{
+	const size_t size = st_mult(n, s);
+	char buf[1024];
+
+	if (!n)
+		return 0;
+	if (!b || !cmp)
+		return -1;
+
+	if (size < sizeof(buf)) {
+		/* The temporary array fits on the small on-stack buffer. */
+		msort_with_tmp(b, n, s, cmp, buf, ctx);
+	} else {
+		/* It's somewhat large, so malloc it.  */
+		char *tmp = xmalloc(size);
+		msort_with_tmp(b, n, s, cmp, tmp, ctx);
+		free(tmp);
+	}
+	return 0;
+}
diff --git a/compat/winansi.c b/compat/winansi.c
index 3c9ed3cfe0..82b89ab137 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -494,19 +494,16 @@ static HANDLE swap_osfhnd(int fd, HANDLE new_handle)
 	 * It is because of this implicit close() that we created the
 	 * copy of the original.
 	 *
-	 * Note that the OS can recycle HANDLE (numbers) just like it
-	 * recycles fd (numbers), so we must update the cached value
-	 * of "console".  You can use GetFileType() to see that
-	 * handle and _get_osfhandle(fd) may have the same number
-	 * value, but they refer to different actual files now.
+	 * Note that we need to update the cached console handle to the
+	 * duplicated one because the dup2() call will implicitly close
+	 * the original one.
 	 *
 	 * Note that dup2() when given target := {0,1,2} will also
 	 * call SetStdHandle(), so we don't need to worry about that.
 	 */
-	dup2(new_fd, fd);
 	if (console == handle)
 		console = duplicate;
-	handle = INVALID_HANDLE_VALUE;
+	dup2(new_fd, fd);
 
 	/* Close the temp fd.  This explicitly closes "new_handle"
 	 * (because it has been associated with it).