iobuf: Add the IOBUF_INPUT_TEMP type to improve input temp handling.

* common/iobuf.h (enum iobuf_use): Add new member, IOBUF_INPUT_TEMP.
* common/iobuf.c (iobuf_temp_with_content): Create the iobuf as an
IOBUF_INPUT_TEMP, not an IOBUF_INPUT buffer.  Assert that LENGTH ==
A->D.SIZE.
(iobuf_push_filter2): If A is an IOBUF_INPUT_TEMP, then make the new
filter an IOBUF_INPUT filter and set its buffer size to
IOBUF_BUFFER_SIZE.
(underflow): If A is an IOBUF_INPUT_TEMP, then just return EOF; don't
remove already read data.
(iobuf_seek): If A is an IOBUF_INPUT_TEMP, don't discard the buffered
data.
(iobuf_alloc): Allow USE == IOBUF_INPUT_TEMP.
(pop_filter): Allow USE == IOBUF_INPUT_TEMP.
(iobuf_peek): Allow USE == IOBUF_INPUT_TEMP.
(iobuf_writebyte): Fail if USE == IOBUF_INPUT_TEMP.
(iobuf_write): Fail if USE == IOBUF_INPUT_TEMP.
(iobuf_writestr): Fail if USE == IOBUF_INPUT_TEMP.
(iobuf_flush_temp): Fail if USE == IOBUF_INPUT_TEMP.

--
Signed-off-by: Neal H. Walfield <[email protected]>.

Introduce a new iobuf type, IOBUF_INPUT_TEMP.  Use this for the iobuf
created by iobuf_temp_with_content instead of IOBUF_INPUT.  This was
necessary so that seeking and peeking correctly work on this type of
iobuf.  In particular, seeking didn't work because we discarded the
buffered data and peeking didn't work because we discarded data which
was already read, which made seeking later impossible.

1 files changed, 22 insertions, 17 deletions

diff --git a/common/iobuf.c b/common/iobuf.c
index a6786b199..795ff11b1 100644
--- a/common/iobuf.c
+++ b/common/iobuf.c
@@ -1099,7 +1099,7 @@ iobuf_alloc (int use, size_t bufsize)
   iobuf_t a;
   static int number = 0;
 
-  assert (use == IOBUF_INPUT
+  assert (use == IOBUF_INPUT || use == IOBUF_INPUT_TEMP
 	  || use == IOBUF_OUTPUT || use == IOBUF_OUTPUT_TEMP);
   if (bufsize == 0)
     {
@@ -1220,7 +1220,8 @@ iobuf_temp_with_content (const char *buffer, size_t length)
   iobuf_t a;
   int i;
 
-  a = iobuf_alloc (IOBUF_INPUT, length);
+  a = iobuf_alloc (IOBUF_INPUT_TEMP, length);
+  assert (length == a->d.size);
   /* memcpy (a->d.buf, buffer, length); */
   for (i=0; i < length; i++)
     a->d.buf[i] = buffer[i];
@@ -1619,6 +1620,12 @@ iobuf_push_filter2 (iobuf_t a,
 	 size.  */
       a->d.size = IOBUF_BUFFER_SIZE;
     }
+  else if (a->use == IOBUF_INPUT_TEMP)
+    /* Same idea as above.  */
+    {
+      a->use = IOBUF_INPUT;
+      a->d.size = IOBUF_BUFFER_SIZE;
+    }
 
   /* The new filter (A) gets a new buffer.
 
@@ -1678,7 +1685,7 @@ pop_filter (iobuf_t a, int (*f) (void *opaque, int control,
   if (DBG_IOBUF)
     log_debug ("iobuf-%d.%d: pop '%s'\n",
 	       a->no, a->subno, iobuf_desc (a));
-  if (a->use == IOBUF_OUTPUT_TEMP)
+  if (a->use == IOBUF_INPUT_TEMP || a->use == IOBUF_OUTPUT_TEMP)
     {
       /* This should be the last filter in the pipeline.  */
       assert (! a->chain);
@@ -1765,6 +1772,11 @@ underflow (iobuf_t a, int clear_pending_eof)
 	       (int) a->d.size, (int) (a->d.len - a->d.start),
 	       (int) (a->d.size - (a->d.len - a->d.start)));
 
+  if (a->use == IOBUF_INPUT_TEMP)
+    /* By definition, there isn't more data to read into the
+       buffer.  */
+    return -1;
+
   assert (a->use == IOBUF_INPUT);
 
   /* If there is still some buffered data, then move it to the start
@@ -2056,7 +2068,7 @@ iobuf_peek (iobuf_t a, byte * buf, unsigned buflen)
   int n = 0;
 
   assert (buflen > 0);
-  assert (a->use == IOBUF_INPUT);
+  assert (a->use == IOBUF_INPUT || a->use == IOBUF_INPUT_TEMP);
 
   if (buflen > a->d.size)
     /* We can't peek more than we can buffer.  */
@@ -2097,7 +2109,7 @@ iobuf_writebyte (iobuf_t a, unsigned int c)
 {
   int rc;
 
-  if (a->use == IOBUF_INPUT)
+  if (a->use == IOBUF_INPUT || a->use == IOBUF_INPUT_TEMP)
     {
       log_bug ("iobuf_writebyte called on an input pipeline!\n");
       return -1;
@@ -2119,7 +2131,7 @@ iobuf_write (iobuf_t a, const void *buffer, unsigned int buflen)
   const unsigned char *buf = (const unsigned char *)buffer;
   int rc;
 
-  if (a->use == IOBUF_INPUT)
+  if (a->use == IOBUF_INPUT || a->use == IOBUF_INPUT_TEMP)
     {
       log_bug ("iobuf_write called on an input pipeline!\n");
       return -1;
@@ -2152,7 +2164,7 @@ iobuf_write (iobuf_t a, const void *buffer, unsigned int buflen)
 int
 iobuf_writestr (iobuf_t a, const char *buf)
 {
-  if (a->use == IOBUF_INPUT)
+  if (a->use == IOBUF_INPUT || a->use == IOBUF_INPUT_TEMP)
     {
       log_bug ("iobuf_writestr called on an input pipeline!\n");
       return -1;
@@ -2200,7 +2212,7 @@ iobuf_temp_to_buffer (iobuf_t a, byte * buffer, size_t buflen)
 void
 iobuf_flush_temp (iobuf_t temp)
 {
-  if (temp->use == IOBUF_INPUT)
+  if (temp->use == IOBUF_INPUT || temp->use == IOBUF_INPUT_TEMP)
     log_bug ("iobuf_writestr called on an input pipeline!\n");
   while (temp->chain)
     pop_filter (temp, temp->filter, NULL);
@@ -2379,10 +2391,9 @@ iobuf_seek (iobuf_t a, off_t newpos)
 	  return -1;
 	}
 #endif
+      /* Discard the buffer it is not a temp stream.  */
+      a->d.len = 0;
     }
-  /* Discard the buffer it is not a temp stream.  */
-  if (a->use != IOBUF_OUTPUT_TEMP)
-    a->d.len = 0;
   a->d.start = 0;
   a->nbytes = 0;
   a->nlimit = 0;
@@ -2409,10 +2420,6 @@ iobuf_seek (iobuf_t a, off_t newpos)
 }
 
 
-
-
-
-
 const char *
 iobuf_get_real_fname (iobuf_t a)
 {
@@ -2430,7 +2437,6 @@ iobuf_get_real_fname (iobuf_t a)
   return NULL;
 }
 
-
 const char *
 iobuf_get_fname (iobuf_t a)
 {
@@ -2462,7 +2468,6 @@ iobuf_set_partial_block_mode (iobuf_t a, size_t len)
 {
   block_filter_ctx_t *ctx = xcalloc (1, sizeof *ctx);
 
-  assert (a->use == IOBUF_INPUT || a->use == IOBUF_OUTPUT);
   ctx->use = a->use;
   if (!len)
     {