Optimize readline/readdelim/getdelim calls.

This speeds up common reading operations by factor of 4-6.

* include/mailutils/stream.h (mu_stream_readdelim): New proto.
* include/mailutils/sys/stream.h (_mu_stream) <readdelim>: New method.
* mailbox/stream.c (_stream_scandelim, _stream_readdelim): New functions.
(mu_stream_readdelim): New function.
(mu_stream_readline): Rewrite using mu_stream_readdelim.
(mu_stream_getdelim): Optimize.

* mailbox/amd.c (amd_body_stream_readdelim): New function.
(_amd_attach_message): Set the readdelim method.
* mailbox/header.c: Add a placeholder for readdelim method.
* mailbox/message.c (_message_stream_readdelim): New function.
(_message_stream_create): Set the readdelim method.
* mailbox/streamref.c (_streamref_readdelim): New function.
(mu_streamref_create_abridged): Set the readdelim method.

@@ -74,6 +74,8 @@ int mu_stream_seek (mu_stream_t stream, mu_off_t offset, int whence,
 int mu_stream_set_buffer (mu_stream_t stream, enum mu_buffer_type type,
 			  size_t size);
 int mu_stream_read (mu_stream_t stream, void *buf, size_t size, size_t *pread);
+int mu_stream_readdelim (mu_stream_t stream, char *buf, size_t size,
+			 int delim, size_t *pread);
 int mu_stream_readline (mu_stream_t stream, char *buf, size_t size, size_t *pread);
 int mu_stream_getdelim (mu_stream_t stream, char **pbuf, size_t *psize,
 			int delim, size_t *pread);

@@ -41,6 +41,7 @@ struct _mu_stream
   int last_err;
 
   int (*read) (struct _mu_stream *, char *, size_t, size_t *);
+  int (*readdelim) (struct _mu_stream *, char *, size_t, int, size_t *);
   int (*write) (struct _mu_stream *, const char *, size_t, size_t *);
   int (*flush) (struct _mu_stream *);
   int (*open) (struct _mu_stream *);

@@ -117,6 +117,10 @@ static int amd_envelope_sender (mu_envelope_t envelope, char *buf, size_t len,
 static int amd_body_stream_read (mu_stream_t str, char *buffer,
 				 size_t buflen,
 				 size_t *pnread);
+static int amd_body_stream_readdelim (mu_stream_t is,
+				      char *buffer, size_t buflen,
+				      int delim,
+				      size_t *pnread);
 static int amd_body_stream_size (mu_stream_t str, mu_off_t *psize);
 static int amd_body_stream_seek (mu_stream_t str, mu_off_t off, int whence,
 				 mu_off_t *presult);
@@ -487,6 +491,7 @@ _amd_attach_message (mu_mailbox_t mailbox, struct _amd_message *mhm,
 	return ENOMEM;
       }
     str->stream.read = amd_body_stream_read;
+    str->stream.readdelim = amd_body_stream_readdelim;
     str->stream.size = amd_body_stream_size;
     str->stream.seek = amd_body_stream_seek;
     mu_body_set_stream (body, (mu_stream_t) str, msg);
@@ -1635,13 +1640,75 @@ amd_body_stream_read (mu_stream_t is, char *buffer, size_t buflen,
 }
 
 static int
+amd_body_stream_readdelim (mu_stream_t is, char *buffer, size_t buflen,
+			   int delim,
+			   size_t *pnread)
+{
+  struct _amd_body_stream *amdstr = (struct _amd_body_stream *)is;
+  mu_body_t body = amdstr->body;
+  mu_message_t msg = mu_body_get_owner (body);
+  struct _amd_message *mhm = mu_message_get_owner (msg);
+  size_t nread = 0;
+  int status = 0;
+
+  amd_pool_open (mhm);
+
+  if (buffer == NULL || buflen == 0)
+    {
+      if (pnread)
+	*pnread = nread;
+      return 0;
+    }
+
+  mu_monitor_rdlock (mhm->amd->mailbox->monitor);
+#ifdef WITH_PTHREAD
+  /* read() is cancellation point since we're doing a potentially
+     long operation.  Lets make sure we clean the state.  */
+  pthread_cleanup_push (amd_cleanup, (void *)mhm->amd->mailbox);
+#endif
+
+  status = mu_stream_seek (mhm->stream, mhm->body_start + amdstr->off,
+			   MU_SEEK_SET, NULL);
+  if (status)
+    {
+      buflen--;
+      while (buflen)
+	{
+	  size_t ln, rdsize;
+	  
+	  ln = mhm->body_end - (mhm->body_start + amdstr->off);
+	  if (ln > 0)
+	    {
+	      rdsize = ((size_t)ln < buflen) ? (size_t)ln : buflen;
+	      status = mu_stream_readdelim (mhm->stream, buffer, rdsize,
+					    delim, &rdsize);
+	      amdstr->off += nread;
+	      nread += rdsize;
+	      if (status)
+		break;
+	      buflen -= rdsize;
+	      buffer += rdsize;
+	    }
+	}
+    }
+
+  mu_monitor_unlock (mhm->amd->mailbox->monitor);
+#ifdef WITH_PTHREAD
+  pthread_cleanup_pop (0);
+#endif
+
+  if (pnread)
+    *pnread = nread;
+  return status;
+}
+
+static int
 amd_body_stream_seek (mu_stream_t str, mu_off_t off, int whence,
 		      mu_off_t *presult)
 {
   size_t size;
   struct _amd_body_stream *amdstr = (struct _amd_body_stream *)str;
   mu_message_t msg = mu_body_get_owner (amdstr->body);
-  struct _amd_message *mhm = mu_message_get_owner (msg);
   
   amd_body_size (amdstr->body, &size);
   switch (whence)

@@ -999,6 +999,59 @@ header_read (mu_stream_t is, char *buffer, size_t buflen, size_t *pnread)
   return 0;
 }
 
+#if 0
+/* FIXME: Implement header_readdelim based on this: */
+static int
+_header_readline (mu_stream_t is, char *buffer, size_t buflen, size_t *pnread)
+{
+  struct _mu_header_stream *hstr = (struct _mu_header_stream *) is;
+  mu_header_t header = hstr->hdr;
+  struct mu_hdrent *ent;
+  size_t ent_off;
+  int status;
+  size_t strsize;
+  char *start, *end;
+
+  if (buflen == 0)
+    return EINVAL;
+
+  header = mu_stream_get_owner (is);
+  status = mu_header_fill (header);
+  if (status)
+    return status;
+  if (mu_hdrent_find_stream_pos (header, hstr->off, &ent, &ent_off))
+    {
+      if (pnread)
+	*pnread = 0;
+      return 0;
+    }
+
+  buflen--; /* Account for the terminating nul */
+
+  mu_hdrent_fixup (header, ent);
+  strsize = MU_STR_SIZE (ent->nlen, ent->vlen) - ent_off;
+  start = MU_HDRENT_NAME (header, ent) + ent_off;
+  end = strchr (start, '\n');
+  if (end)
+    {
+      size_t len = end - start + 1;
+      if (len < strsize)
+	strsize = len;
+    }
+
+  if (strsize < buflen)
+    buflen = strsize;
+
+  memcpy (buffer, start, buflen);
+  buffer[buflen] = 0;
+  hstr->off += buflen;
+  mu_hdrent_unroll_fixup (header, ent);
+  if (pnread)
+    *pnread = buflen;
+  return 0;
+}
+#endif
+
 static int
 header_write (mu_stream_t os, const char *buf, size_t buflen, size_t *pnwrite)
 {

@@ -243,6 +243,31 @@ _message_stream_read (struct _mu_stream *str, char *buf, size_t bufsize,
   return rc;
 }
 
+static int
+_message_stream_readdelim (struct _mu_stream *str, char *buf, size_t bufsize,
+			   int delim, size_t *pnread)
+{
+  struct _mu_message_stream *sp = (struct _mu_message_stream *)str;
+  size_t nread = 0;
+  int rc;
+  
+  while (bufsize)
+    {
+      size_t n;
+      rc = _check_stream_state (sp);
+      if (rc)
+	break;
+      if (sp->state == _mss_eof)
+	break;
+      rc = mu_stream_readdelim (sp->transport, buf, bufsize, delim, &n);
+      nread += n;
+      buf += n;
+      bufsize -= n;
+    }
+  *pnread = nread;
+  return rc;
+}  
+
 #if 0
 static int
 _message_stream_write (struct _mu_stream *str,
@@ -266,6 +291,7 @@ _message_stream_create (mu_stream_t *pmsg, mu_message_t msg, int flags)
     return ENOMEM;
 
   sp->stream.read = _message_stream_read;
+  sp->stream.readdelim = _message_stream_readdelim;
   /* FIXME: Write is not defined */
   /*  sp->stream.write = _message_stream_write;*/
   sp->stream.done = _message_stream_done;

@@ -536,22 +536,54 @@ mu_stream_read (mu_stream_t stream, void *buf, size_t size, size_t *pread)
 }
 
 int
-mu_stream_readline (mu_stream_t stream, char *buf, size_t size, size_t *pread)
+_stream_scandelim (mu_stream_t stream, char *buf, size_t size, int delim,
+		   size_t *pnread)
+{
+  int rc = 0;
+  size_t nread = 0;
+  
+  size--;
+  while (size)
+    {
+      char *p;
+      size_t len;
+      
+      if (stream->level == 0)
+	{
+	  if ((rc = _stream_fill_buffer (stream)) || stream->level == 0)
+	    break;
+	}
+      
+      p = memchr (stream->cur, delim, stream->level);
+      len = p ? p - stream->cur + 1 : stream->level;
+      if (len > size)
+	len = size;
+      memcpy (buf, stream->cur, len);
+      _stream_advance_buffer (stream, len);
+      buf += len;
+      size -= len;
+      nread += len;
+    }
+  *buf = 0;
+  *pnread = nread;
+  return rc;
+}
+
+static int
+_stream_readdelim (mu_stream_t stream, char *buf, size_t size,
+		   int delim, size_t *pread)
 {
   int rc;
   char c;
   size_t n = 0, rdn;
     
-  if (size == 0)
-    return EINVAL;
-    
   size--;
   for (n = 0;
        n < size && (rc = mu_stream_read (stream, &c, 1, &rdn)) == 0 && rdn;)
     {
       *buf++ = c;
       n++;
-      if (c == '\n')
+      if (c == delim)
 	break;
     }
   *buf = 0;
@@ -561,6 +593,30 @@ mu_stream_readline (mu_stream_t stream, char *buf, size_t size, size_t *pread)
 }
 
 int
+mu_stream_readdelim (mu_stream_t stream, char *buf, size_t size,
+		     int delim, size_t *pread)
+{
+  int rc;
+  
+  if (size == 0)
+    return EINVAL;
+    
+  if (stream->readdelim)
+    rc = stream->readdelim (stream, buf, size, delim, pread);
+  else if (stream->buftype != mu_buffer_none)
+    rc = _stream_scandelim (stream, buf, size, delim, pread);
+  else
+    rc = _stream_readdelim (stream, buf, size, delim, pread);
+  return rc;
+}
+
+int
+mu_stream_readline (mu_stream_t stream, char *buf, size_t size, size_t *pread)
+{
+  return mu_stream_readdelim (stream, buf, size, '\n', pread);
+}
+
+int
 mu_stream_getdelim (mu_stream_t stream, char **pbuf, size_t *psize,
 		    int delim, size_t *pread)
 {
@@ -581,13 +637,8 @@ mu_stream_getdelim (mu_stream_t stream, char **pbuf, size_t *psize,
     
   for (;;)
     {
-      char c;
       size_t rdn;
 
-      rc = mu_stream_read (stream, &c, 1, &rdn);
-      if (rc || rdn == 0)
-	break;
-	
       /* Make enough space for len+1 (for final NUL) bytes.  */
       if (cur_len + 1 >= n)
 	{
@@ -615,10 +666,20 @@ mu_stream_getdelim (mu_stream_t stream, char **pbuf, size_t *psize,
 	  n = needed;
 	}
 
-      lineptr[cur_len] = c;
-      cur_len++;
+      if (stream->readdelim)
+	rc = stream->readdelim (stream, lineptr + cur_len, n - cur_len, delim,
+				&rdn);
+      else if (stream->buftype != mu_buffer_none)
+	rc = _stream_scandelim (stream, lineptr + cur_len, n - cur_len, delim,
+				&rdn);
+      else
+	rc = mu_stream_read (stream, lineptr + cur_len, 1, &rdn);
+
+      if (rc || rdn == 0)
+	break;
+      cur_len += rdn;
       
-      if (c == delim)
+      if (lineptr[cur_len - 1] == delim)
 	break;
     }
   lineptr[cur_len] = '\0';

@@ -69,6 +69,16 @@ _streamref_read (struct _mu_stream *str, char *buf, size_t bufsize,
 }
 
 static int
+_streamref_readdelim (struct _mu_stream *str, char *buf, size_t bufsize,
+		      int delim, size_t *pnread)
+{
+  struct _mu_streamref *sp = (struct _mu_streamref *)str;
+  return streamref_return (sp, mu_stream_readdelim (sp->transport,
+						    buf, bufsize,
+						    delim, pnread));
+}
+
+static int
 _streamref_write (struct _mu_stream *str, const char *buf, size_t bufsize,
 		  size_t *pnwrite)
 {
@@ -264,6 +274,7 @@ mu_streamref_create_abridged (mu_stream_t *pref, mu_stream_t str,
   mu_stream_ref (str);
 
   sp->stream.read = _streamref_read; 
+  sp->stream.readdelim = _streamref_readdelim; 
   sp->stream.write = _streamref_write;
   sp->stream.flush = _streamref_flush;
   sp->stream.open = _streamref_open;