[v3,3/3] pkt-line: extract out PACKET_HEADER_SIZE
diff mbox series

Message ID 00c19983fd99d7c335238725011e32785cb2b2a5.1592934880.git.liu.denton@gmail.com
State New
Headers show
Series
  • pkt-line: war on magical `4` literal
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Commit Message

Denton Liu June 23, 2020, 5:55 p.m. UTC
In pkt-line and remote-curl, we have many instances of magic `4`
literals floating around which represent the number of bytes in the
packet line length header. Instead of using these magic numbers, replace
them with constant expressions.

In most cases, replace the `4` with `PACKET_HEADER_SIZE`. However, in
the case where there's a `char array[PACKET_HEADER_SIZE]`  and we are
reading data into it, replace the `4` with a `sizeof(array)` so that
it's clear that the logic has something to do with that array.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 pkt-line.c    | 20 ++++++++++----------
 pkt-line.h    |  6 ++++--
 remote-curl.c | 29 +++++++++++++++--------------
 3 files changed, 29 insertions(+), 26 deletions(-)

Patch
diff mbox series

diff --git a/pkt-line.c b/pkt-line.c
index e29f427b19..d451f0b67c 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -165,7 +165,7 @@  static void format_packet(struct strbuf *out, const char *prefix,
 		die(_("protocol error: impossibly long line"));
 
 	set_packet_header(&out->buf[orig_len], n);
-	packet_trace(out->buf + orig_len + 4, n - 4, 1);
+	packet_trace(out->buf + orig_len + PACKET_HEADER_SIZE, n - PACKET_HEADER_SIZE, 1);
 }
 
 static int packet_write_fmt_1(int fd, int gently, const char *prefix,
@@ -211,13 +211,13 @@  static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 	static char packet_write_buffer[LARGE_PACKET_MAX];
 	size_t packet_size;
 
-	if (size > sizeof(packet_write_buffer) - 4)
+	if (size > sizeof(packet_write_buffer) - PACKET_HEADER_SIZE)
 		return error(_("packet write failed - data exceeds max packet size"));
 
 	packet_trace(buf, size, 1);
-	packet_size = size + 4;
+	packet_size = size + PACKET_HEADER_SIZE;
 	set_packet_header(packet_write_buffer, packet_size);
-	memcpy(packet_write_buffer + 4, buf, size);
+	memcpy(packet_write_buffer + PACKET_HEADER_SIZE, buf, size);
 	if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0)
 		return error(_("packet write failed"));
 	return 0;
@@ -325,7 +325,7 @@  static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 	return ret;
 }
 
-int packet_length(const char lenbuf_hex[4])
+int packet_length(const char lenbuf_hex[PACKET_HEADER_SIZE])
 {
 	int val = hex2chr(lenbuf_hex);
 	return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
@@ -337,9 +337,9 @@  enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 						int options)
 {
 	int len;
-	char linelen[4];
+	char linelen[PACKET_HEADER_SIZE];
 
-	if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
+	if (get_packet_data(fd, src_buffer, src_len, linelen, sizeof(linelen), options) < 0) {
 		*pktlen = -1;
 		return PACKET_READ_EOF;
 	}
@@ -360,11 +360,11 @@  enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 		packet_trace_str("0002", 0);
 		*pktlen = 0;
 		return PACKET_READ_RESPONSE_END;
-	} else if (len < 4) {
+	} else if (len < PACKET_HEADER_SIZE) {
 		die(_("protocol error: bad line length %d"), len);
 	}
 
-	len -= 4;
+	len -= sizeof(linelen);
 	if ((unsigned)len >= size)
 		die(_("protocol error: bad line length %d"), len);
 
@@ -382,7 +382,7 @@  enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 
 	if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 	    starts_with(buffer, "ERR "))
-		die(_("remote error: %s"), buffer + 4);
+		die(_("remote error: %s"), buffer + PACKET_HEADER_SIZE);
 
 	*pktlen = len;
 	return PACKET_READ_NORMAL;
diff --git a/pkt-line.h b/pkt-line.h
index 5b373fe4cd..d6121b8044 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -5,6 +5,8 @@ 
 #include "strbuf.h"
 #include "sideband.h"
 
+#define PACKET_HEADER_SIZE 4
+
 /*
  * Write a packetized stream, where each line is preceded by
  * its length (including the header) as a 4-byte hex number.
@@ -82,7 +84,7 @@  int packet_read(int fd, char **src_buffer, size_t *src_len, char
  * If lenbuf_hex contains non-hex characters, return -1. Otherwise, return the
  * numeric value of the length header.
  */
-int packet_length(const char lenbuf_hex[4]);
+int packet_length(const char lenbuf_hex[PACKET_HEADER_SIZE]);
 
 /*
  * Read a packetized line into a buffer like the 'packet_read()' function but
@@ -211,7 +213,7 @@  enum packet_read_status packet_reader_peek(struct packet_reader *reader);
 
 #define DEFAULT_PACKET_MAX 1000
 #define LARGE_PACKET_MAX 65520
-#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
+#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - PACKET_HEADER_SIZE)
 extern char packet_buffer[LARGE_PACKET_MAX];
 
 struct packet_writer {
diff --git a/remote-curl.c b/remote-curl.c
index a2cbef546b..c99a2a514a 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -536,8 +536,8 @@  struct rpc_state {
 	unsigned initial_buffer : 1;
 
 	/*
-	 * Whenever a pkt-line is read into buf, append the 4 characters
-	 * denoting its length before appending the payload.
+	 * Whenever a pkt-line is read into buf, append the PACKET_HEADER_SIZE
+	 * characters denoting its length before appending the payload.
 	 */
 	unsigned write_line_lengths : 1;
 
@@ -556,8 +556,9 @@  struct rpc_state {
  * rpc->buf and rpc->len if there is enough space. Returns 1 if there was
  * enough space, 0 otherwise.
  *
- * If rpc->write_line_lengths is true, appends the line length as a 4-byte
- * hexadecimal string before appending the result described above.
+ * If rpc->write_line_lengths is true, appends the line length as a
+ * PACKET_HEADER_SIZE-byte hexadecimal string before appending the result
+ * described above.
  *
  * Writes the total number of bytes appended into appended.
  */
@@ -569,8 +570,8 @@  static int rpc_read_from_out(struct rpc_state *rpc, int options,
 	int pktlen_raw;
 
 	if (rpc->write_line_lengths) {
-		left = rpc->alloc - rpc->len - 4;
-		buf = rpc->buf + rpc->len + 4;
+		left = rpc->alloc - rpc->len - PACKET_HEADER_SIZE;
+		buf = rpc->buf + rpc->len + PACKET_HEADER_SIZE;
 	} else {
 		left = rpc->alloc - rpc->len;
 		buf = rpc->buf + rpc->len;
@@ -582,7 +583,7 @@  static int rpc_read_from_out(struct rpc_state *rpc, int options,
 	*status = packet_read_with_status(rpc->out, NULL, NULL, buf,
 			left, &pktlen_raw, options);
 	if (*status != PACKET_READ_EOF) {
-		*appended = pktlen_raw + (rpc->write_line_lengths ? 4 : 0);
+		*appended = pktlen_raw + (rpc->write_line_lengths ? PACKET_HEADER_SIZE : 0);
 		rpc->len += *appended;
 	}
 
@@ -593,7 +594,7 @@  static int rpc_read_from_out(struct rpc_state *rpc, int options,
 				die(_("shouldn't have EOF when not gentle on EOF"));
 			break;
 		case PACKET_READ_NORMAL:
-			set_packet_header(buf - 4, *appended);
+			set_packet_header(buf - PACKET_HEADER_SIZE, *appended);
 			break;
 		case PACKET_READ_DELIM:
 			memcpy(buf - strlen("0001"), "0001", strlen("0001"));
@@ -682,7 +683,7 @@  static curlioerr rpc_ioctl(CURL *handle, int cmd, void *clientp)
 #endif
 
 struct check_pktline_state {
-	char len_buf[4];
+	char len_buf[PACKET_HEADER_SIZE];
 	int len_filled;
 	int remaining;
 };
@@ -691,7 +692,7 @@  static void check_pktline(struct check_pktline_state *state, const char *ptr, si
 {
 	while (size) {
 		if (!state->remaining) {
-			int digits_remaining = 4 - state->len_filled;
+			int digits_remaining = sizeof(state->len_buf) - state->len_filled;
 			if (digits_remaining > size)
 				digits_remaining = size;
 			memcpy(&state->len_buf[state->len_filled], ptr, digits_remaining);
@@ -699,16 +700,16 @@  static void check_pktline(struct check_pktline_state *state, const char *ptr, si
 			ptr += digits_remaining;
 			size -= digits_remaining;
 
-			if (state->len_filled == 4) {
+			if (state->len_filled == sizeof(state->len_buf)) {
 				state->remaining = packet_length(state->len_buf);
 				if (state->remaining < 0) {
 					die(_("remote-curl: bad line length character: %.4s"), state->len_buf);
 				} else if (state->remaining == 2) {
 					die(_("remote-curl: unexpected response end packet"));
-				} else if (state->remaining < 4) {
+				} else if (state->remaining < sizeof(state->len_buf)) {
 					state->remaining = 0;
 				} else {
-					state->remaining -= 4;
+					state->remaining -= sizeof(state->len_buf);
 				}
 				state->len_filled = 0;
 			}
@@ -1469,7 +1470,7 @@  int cmd_main(int argc, const char **argv)
 			parse_fetch(&buf);
 
 		} else if (!strcmp(buf.buf, "list") || starts_with(buf.buf, "list ")) {
-			int for_push = !!strstr(buf.buf + 4, "for-push");
+			int for_push = !!strstr(buf.buf + PACKET_HEADER_SIZE, "for-push");
 			output_refs(get_refs(for_push));
 
 		} else if (starts_with(buf.buf, "push ")) {