From 26557fc1b37480d184a32de025b060aa1aa231db Mon Sep 17 00:00:00 2001
From: Jonathan Nieder <jrnieder@gmail.com>
Date: Tue, 28 Dec 2010 04:26:17 -0600
Subject: vcs-svn: make buffer_copy_bytes return length read

Currently buffer_copy_bytes does not report to its caller whether
it encountered an early end of file.

Add a return value representing the number of bytes read (but not
the number of bytes copied).  This way all three unusual conditions
can be distinguished: input error with buffer_ferror, output error
with ferror(outfile), early end of input by checking the return
value.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>

diff --git a/vcs-svn/line_buffer.c b/vcs-svn/line_buffer.c
index 39d52b8..33e733a 100644
--- a/vcs-svn/line_buffer.c
+++ b/vcs-svn/line_buffer.c
@@ -104,20 +104,20 @@ void buffer_read_binary(struct line_buffer *buf,
 	strbuf_fread(sb, size, buf->infile);
 }
 
-void buffer_copy_bytes(struct line_buffer *buf, off_t len)
+off_t buffer_copy_bytes(struct line_buffer *buf, off_t nbytes)
 {
 	char byte_buffer[COPY_BUFFER_LEN];
-	uint32_t in;
-	while (len > 0 && !feof(buf->infile) && !ferror(buf->infile)) {
-		in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
+	off_t done = 0;
+	while (done < nbytes && !feof(buf->infile) && !ferror(buf->infile)) {
+		off_t len = nbytes - done;
+		size_t in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
 		in = fread(byte_buffer, 1, in, buf->infile);
-		len -= in;
+		done += in;
 		fwrite(byte_buffer, 1, in, stdout);
-		if (ferror(stdout)) {
-			buffer_skip_bytes(buf, len);
-			return;
-		}
+		if (ferror(stdout))
+			return done + buffer_skip_bytes(buf, nbytes - done);
 	}
+	return done;
 }
 
 off_t buffer_skip_bytes(struct line_buffer *buf, off_t nbytes)
diff --git a/vcs-svn/line_buffer.h b/vcs-svn/line_buffer.h
index 7d10f9c..f5c468a 100644
--- a/vcs-svn/line_buffer.h
+++ b/vcs-svn/line_buffer.h
@@ -26,7 +26,8 @@ char *buffer_read_line(struct line_buffer *buf);
 char *buffer_read_string(struct line_buffer *buf, uint32_t len);
 int buffer_read_char(struct line_buffer *buf);
 void buffer_read_binary(struct line_buffer *buf, struct strbuf *sb, uint32_t len);
-void buffer_copy_bytes(struct line_buffer *buf, off_t len);
+/* Returns number of bytes read (not necessarily written). */
+off_t buffer_copy_bytes(struct line_buffer *buf, off_t len);
 off_t buffer_skip_bytes(struct line_buffer *buf, off_t len);
 
 #endif
-- 
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