file_io.c: Cleanup

[wimlib] / src / file_io.c

diff --git a/src/file_io.c b/src/file_io.c
index 2852571c413cb13ea1f29ae4174c1155779b7b11..94f1ced53d5db62e6ceb2aeded40713f62b73674 100644 (file)
--- a/src/file_io.c
+++ b/src/file_io.c
@@ -25,7 +25,6 @@
 #  include "config.h"
 #endif
 
-#include "wimlib/assert.h"
 #include "wimlib/error.h"
 #include "wimlib/file_io.h"
 #include "wimlib/util.h"
@@ -39,8 +38,8 @@
 #include <unistd.h>
 
 
-/* Wrapper around read() that keeps retrying until all requested bytes have been
- * read or until end-of file has occurred.
+/* Wrapper around read() that checks for errors keeps retrying until all
+ * requested bytes have been read or until end-of file has occurred.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS                      (0)
@@ -79,15 +78,17 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
 {
        int ret;
 
+       /* Verify the offset.  */
        if (offset < fd->offset) {
                ERROR("Can't seek backwards in pipe "
                      "(offset %"PRIu64" => %"PRIu64").\n"
-                     "      Make sure the WIM was captured as "
-                     "pipable.",
-                       fd->offset, offset);
+                     "        Make sure the WIM was captured as "
+                     "pipable.", fd->offset, offset);
                errno = ESPIPE;
                return WIMLIB_ERR_RESOURCE_ORDER;
        }
+
+       /* Manually seek to the requested position.  */
        while (fd->offset != offset) {
                size_t bytes_to_read = min(offset - fd->offset, BUFFER_SIZE);
                u8 dummy[bytes_to_read];
@@ -96,13 +97,15 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
                if (ret)
                        return ret;
        }
+
+       /* Do the actual read.  */
        return full_read(fd, buf, count);
 }
 
-/* Wrapper around pread() that keep retrying until all requested bytes have been
- * read or until end-of file has occurred.  This also transparently handle
- * reading from pipe files, but the caller needs to be sure the requested offset
- * is greater than or equal to the current offset, or else
+/* Wrapper around pread() that checks for errors and keeps retrying until all
+ * requested bytes have been read or until end-of file has occurred.  This also
+ * transparently handle reading from pipe files, but the caller needs to be sure
+ * the requested offset is greater than or equal to the current offset, or else
  * WIMLIB_ERR_RESOURCE_ORDER will be returned.
  *
  * Return values:
@@ -110,7 +113,7 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
  *     WIMLIB_ERR_READ                         (errno set)
  *     WIMLIB_ERR_UNEXPECTED_END_OF_FILE       (errno set to 0)
  *     WIMLIB_ERR_RESOURCE_ORDER               (errno set to ESPIPE)
- * */
+ */
 int
 full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
 {
@@ -133,7 +136,6 @@ full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
                        } else if (errno == EINTR) {
                                continue;
                        } else if (errno == ESPIPE) {
-                               wimlib_assert(count == bytes_remaining);
                                fd->is_pipe = 1;
                                goto is_pipe;
                        } else {
@@ -147,8 +149,8 @@ is_pipe:
        return pipe_read(fd, buf, count, offset);
 }
 
-/* Wrapper around write() that keeps retrying until all requested bytes have
- * been written.
+/* Wrapper around write() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS                      (0)
@@ -176,8 +178,8 @@ full_write(struct filedes *fd, const void *buf, size_t count)
 }
 
 
-/* Wrapper around pwrite() that keep retrying until all requested bytes have been
- * written.
+/* Wrapper around pwrite() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS      (0)
@@ -204,8 +206,8 @@ full_pwrite(struct filedes *fd, const void *buf, size_t count, off_t offset)
        return 0;
 }
 
-/* Wrapper around writev() that keep retrying until all requested bytes have been
- * written.
+/* Wrapper around writev() that checks for errors and keep retrying until all
+ * requested bytes have been written.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS      (0)
@@ -219,7 +221,7 @@ full_writev(struct filedes *fd, struct iovec *iov, int iovcnt)
                ssize_t bytes_written;
 
                bytes_written = writev(fd->fd, iov, iovcnt);
-               if (bytes_written < 0) {
+               if (unlikely(bytes_written < 0)) {
                        if (errno == EINTR)
                                continue;
                        return WIMLIB_ERR_WRITE;