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 39d52b88b754338f7ad86cb71c1b7998f110f272..33e733a04c2b694a7dce80c8404edd464fe1a6b7 100644 (file)
--- 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 7d10f9c751656ab05a22438bbd7eb52fa9573a38..f5c468afa45f1f567dc5cc2b3e2e748b79fe5cb0 100644 (file)
--- 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