limit_data.chunk_start = wtimer_read (timer);
}
-#define MIN(i, j) ((i) <= (j) ? (i) : (j))
+#ifndef MIN
+# define MIN(i, j) ((i) <= (j) ? (i) : (j))
+#endif
/* Reads the contents of file descriptor FD, until it is closed, or a
read error occurs. The data is read in 8K chunks, and stored to
\f
typedef const char *(*finder_t) PARAMS ((const char *, int, int));
-/* Driver for fd_read_line and fd_read_head: keeps reading data until
- a terminator (as decided by FINDER) occurs in the data. The trick
- is that the data is first peeked at, and only then actually read.
- That way the data after the terminator is never read. */
+/* Read a hunk of data from FD, up until a terminator. The terminator
+ is whatever the TERMINATOR function determines it to be; for
+ example, it can be a line of data, or the head of an HTTP response.
+ The function returns the data read allocated with malloc.
-static char *
-fd_read_until (int fd, finder_t finder, int bufsize)
+ In case of error, NULL is returned. In case of EOF and no data
+ read, NULL is returned and errno set to 0. In case of EOF with
+ data having been read, the data is returned, but it will
+ (obviously) not contain the terminator.
+
+ The idea is to be able to read a line of input, or otherwise a hunk
+ of text, such as the head of an HTTP request, without crossing the
+ boundary, so that the next call to fd_read etc. reads the data
+ after the hunk. To achieve that, this function does the following:
+
+ 1. Peek at available data.
+
+ 2. Determine whether the peeked data, along with the previously
+ read data, includes the terminator.
+
+ 2a. If yes, read the data until the end of the terminator, and
+ exit.
+
+ 2b. If no, read the peeked data and goto 1.
+
+ The function is careful to assume as little as possible about the
+ implementation of peeking. For example, every peek is followed by
+ a read. If the read returns a different amount of data, the
+ process is retried until all data arrives safely.
+
+ BUFSIZE is the size of the initial buffer expected to read all the
+ data in the typical case.
+
+ This function should be used as a building block for other
+ functions -- see fd_read_line as a simple example. */
+
+char *
+fd_read_hunk (int fd, hunk_terminator_t hunk_terminator, int bufsize)
{
- int size = bufsize, tail = 0;
- char *buf = xmalloc (size);
+ char *hunk = xmalloc (bufsize);
+ int tail = 0; /* tail position in HUNK */
while (1)
{
/* First, peek at the available data. */
- pklen = fd_peek (fd, buf + tail, size - tail, -1);
+ pklen = fd_peek (fd, hunk + tail, bufsize - 1 - tail, -1);
if (pklen < 0)
{
- xfree (buf);
+ xfree (hunk);
return NULL;
}
- end = finder (buf, tail, pklen);
+ end = hunk_terminator (hunk, tail, pklen);
if (end)
{
- /* The data contains the terminator: we'll read the data up
+ /* The data contains the terminator: we'll drain the data up
to the end of the terminator. */
- remain = end - (buf + tail);
- /* Note +1 for trailing \0. */
- if (size < tail + remain + 1)
+ remain = end - (hunk + tail);
+ if (remain == 0)
+ {
+ /* No more data needs to be read. */
+ hunk[tail] = '\0';
+ return hunk;
+ }
+ if (bufsize - 1 < tail + remain)
{
- size = tail + remain + 1;
- buf = xrealloc (buf, size);
+ bufsize = tail + remain + 1;
+ hunk = xrealloc (hunk, bufsize);
}
}
else
how much data we'll get. (Some TCP stacks are notorious for
read returning less data than the previous MSG_PEEK.) */
- rdlen = fd_read (fd, buf + tail, remain, 0);
+ rdlen = fd_read (fd, hunk + tail, remain, 0);
if (rdlen < 0)
{
- xfree_null (buf);
+ xfree_null (hunk);
return NULL;
}
+ tail += rdlen;
+ hunk[tail] = '\0';
+
if (rdlen == 0)
{
if (tail == 0)
{
/* EOF without anything having been read */
- xfree (buf);
+ xfree (hunk);
errno = 0;
return NULL;
}
- /* Return what we received so far. */
- if (size < tail + 1)
- {
- size = tail + 1; /* expand the buffer to receive the
- terminating \0 */
- buf = xrealloc (buf, size);
- }
- buf[tail] = '\0';
- return buf;
+ else
+ /* EOF seen: return the data we've read. */
+ return hunk;
}
- tail += rdlen;
if (end && rdlen == remain)
- {
- /* The end was seen and the data read -- we got what we came
- for. */
- buf[tail] = '\0';
- return buf;
- }
+ /* The terminator was seen and the remaining data drained --
+ we got what we came for. */
+ return hunk;
/* Keep looping until all the data arrives. */
- if (tail == size)
+ if (tail == bufsize - 1)
{
- size <<= 1;
- buf = xrealloc (buf, size);
+ bufsize <<= 1;
+ hunk = xrealloc (hunk, bufsize);
}
}
}
static const char *
-line_terminator (const char *buf, int tail, int peeklen)
+line_terminator (const char *hunk, int oldlen, int peeklen)
{
- const char *p = memchr (buf + tail, '\n', peeklen);
+ const char *p = memchr (hunk + oldlen, '\n', peeklen);
if (p)
/* p+1 because we want the line to include '\n' */
return p + 1;
char *
fd_read_line (int fd)
{
- return fd_read_until (fd, line_terminator, 128);
-}
-
-static const char *
-head_terminator (const char *buf, int tail, int peeklen)
-{
- const char *start, *end;
- if (tail < 4)
- start = buf;
- else
- start = buf + tail - 4;
- end = buf + tail + peeklen;
-
- for (; start < end - 1; start++)
- if (*start == '\n')
- {
- if (start < end - 2
- && start[1] == '\r'
- && start[2] == '\n')
- return start + 3;
- if (start[1] == '\n')
- return start + 2;
- }
- return NULL;
-}
-
-/* Read the request head from FD and return it. The chunk of data is
- allocated using malloc.
-
- If an error occurs, or if no data can be read, NULL is returned.
- In the former case errno indicates the error condition, and in the
- latter case, errno is NULL. */
-
-char *
-fd_read_head (int fd)
-{
- return fd_read_until (fd, head_terminator, 512);
+ return fd_read_hunk (fd, line_terminator, 128);
}
\f
/* Return a printed representation of the download rate, as
rewritten_url = rewrite_shorthand_url (proxy);
if (rewritten_url)
{
- strncpy (rewritten_storage, rewritten_url, sizeof(rewritten_storage));
+ strncpy (rewritten_storage, rewritten_url, sizeof (rewritten_storage));
rewritten_storage[sizeof (rewritten_storage) - 1] = '\0';
proxy = rewritten_storage;
}
projects / wget / blobdiff