Move read_in_full() and write_in_full() to wrapper.c

A few compat/* layer functions call these functions, but we would really
want to keep them thin, without depending too much on the libgit proper.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

wrapper.c

@@ -133,6 +133,44 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
 	}
 }
 
+ssize_t read_in_full(int fd, void *buf, size_t count)
+{
+	char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t loaded = xread(fd, p, count);
+		if (loaded <= 0)
+			return total ? total : loaded;
+		count -= loaded;
+		p += loaded;
+		total += loaded;
+	}
+
+	return total;
+}
+
+ssize_t write_in_full(int fd, const void *buf, size_t count)
+{
+	const char *p = buf;
+	ssize_t total = 0;
+
+	while (count > 0) {
+		ssize_t written = xwrite(fd, p, count);
+		if (written < 0)
+			return -1;
+		if (!written) {
+			errno = ENOSPC;
+			return -1;
+		}
+		count -= written;
+		p += written;
+		total += written;
+	}
+
+	return total;
+}
+
 int xdup(int fd)
 {
 	int ret = dup(fd);

write_or_die.c

@@ -45,44 +45,6 @@ void maybe_flush_or_die(FILE *f, const char *desc)
 	}
 }
 
-ssize_t read_in_full(int fd, void *buf, size_t count)
-{
-	char *p = buf;
-	ssize_t total = 0;
-
-	while (count > 0) {
-		ssize_t loaded = xread(fd, p, count);
-		if (loaded <= 0)
-			return total ? total : loaded;
-		count -= loaded;
-		p += loaded;
-		total += loaded;
-	}
-
-	return total;
-}
-
-ssize_t write_in_full(int fd, const void *buf, size_t count)
-{
-	const char *p = buf;
-	ssize_t total = 0;
-
-	while (count > 0) {
-		ssize_t written = xwrite(fd, p, count);
-		if (written < 0)
-			return -1;
-		if (!written) {
-			errno = ENOSPC;
-			return -1;
-		}
-		count -= written;
-		p += written;
-		total += written;
-	}
-
-	return total;
-}
-
 void fsync_or_die(int fd, const char *msg)
 {
 	if (fsync(fd) < 0) {