5 files changed, 54 insertions, 38 deletions

diff --git a/filter/buffer.c b/filter/buffer.c
index 1b7a0793..79339456 100644
--- a/filter/buffer.c
+++ b/filter/buffer.c
@@ -8,6 +8,7 @@ fz_newbuffer(fz_buffer **bp, int size)
 	b = *bp = fz_malloc(sizeof(fz_buffer));
 	if (!b) return fz_outofmem;
 
+	b->nrefs = 1;
 	b->ownsdata = 1;
 	b->bp = fz_malloc(size);
 	if (!b->bp) { fz_free(b); return fz_outofmem; }
@@ -28,6 +29,7 @@ fz_newbufferwithdata(fz_buffer **bp, unsigned char *data, int size)
 	b = *bp = fz_malloc(sizeof(fz_buffer));
 	if (!b) return fz_outofmem;
 
+	b->nrefs = 1;
 	b->ownsdata = 0;
 	b->bp = data;
 
@@ -39,12 +41,22 @@ fz_newbufferwithdata(fz_buffer **bp, unsigned char *data, int size)
 	return nil;
 }
 
+fz_buffer *
+fz_keepbuffer(fz_buffer *buf)
+{
+	buf->nrefs ++;
+	return buf;
+}
+
 void
 fz_dropbuffer(fz_buffer *buf)
 {
-	if (buf->ownsdata)
-		fz_free(buf->bp);
-	fz_free(buf);
+	if (--buf->nrefs == 0)
+	{
+		if (buf->ownsdata)
+			fz_free(buf->bp);
+		fz_free(buf);
+	}
 }
 
 fz_error *
diff --git a/filter/filec.c b/filter/filec.c
index 4c132b33..5ea3c75a 100644
--- a/filter/filec.c
+++ b/filter/filec.c
@@ -67,8 +67,8 @@ fz_openfile(fz_file **filep, char *path, int mode)
 cleanup:
 	*filep = nil;
 	close(fd);
-	fz_free(file->out);
-	fz_free(file->in);
+	fz_dropbuffer(file->out);
+	fz_dropbuffer(file->in);
 	fz_free(file);
 	return error;
 }
@@ -93,7 +93,7 @@ fz_openbuffer(fz_file **filep, fz_buffer *buf, int mode)
 
 	if (mode == FZ_READ)
 	{
-		file->out = buf;
+		file->out = fz_keepbuffer(buf);
 		error = fz_newbuffer(&file->in, FZ_BUFSIZE);
 		if (error)
 			goto cleanup;
@@ -104,7 +104,7 @@ fz_openbuffer(fz_file **filep, fz_buffer *buf, int mode)
 		error = fz_newbuffer(&file->out, FZ_BUFSIZE);
 		if (error)
 			goto cleanup;
-		file->in = buf;
+		file->in = fz_keepbuffer(buf);
 	}
 
 	return nil;
@@ -130,19 +130,11 @@ fz_closefile(fz_file *file)
 		file->error = nil;
 	}
 
-	if (file->fd == -1)	/* open to buffer not file */
-	{
-		if (file->mode == FZ_READ)
-			fz_dropbuffer(file->in);
-		else
-			fz_dropbuffer(file->out);
-	}
-	else
-	{
-		fz_dropbuffer(file->in);
-		fz_dropbuffer(file->out);
+	if (file->fd != -1)	/* open to real file */
 		close(file->fd);
-	}
+
+	fz_dropbuffer(file->in);
+	fz_dropbuffer(file->out);
 
 	if (file->filter)
 		fz_dropfilter(file->filter);
@@ -178,7 +170,7 @@ fz_pushfilter(fz_file *file, fz_filter *filter)
 			file->in->eof = 0;
 		}
 
-		file->filter = filter;
+		file->filter = fz_keepfilter(filter);
 	}
 
 	else
diff --git a/filter/filer.c b/filter/filer.c
index 29e04558..24f9a214 100644
--- a/filter/filer.c
+++ b/filter/filer.c
@@ -233,6 +233,7 @@ fz_readfile(fz_buffer **bufp, fz_file *file)
 				return fz_outofmem;
 			}
 
+			real->nrefs = 1;
 			real->ownsdata = 1;
 			real->bp = buf;
 			real->rp = buf;
diff --git a/filter/filter.c b/filter/filter.c
index 25bbd441..4bd8c4ff 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -1,8 +1,8 @@
 #include <fitz.h>
 
-fz_error fz_kioneedin = { "<ioneedin>", "<process>", "filter.c", 0, 1 };
-fz_error fz_kioneedout = { "<ioneedout>", "<process>", "filter.c", 0, 1 };
-fz_error fz_kiodone = { "<iodone>", "<process>", "filter.c", 0, 1 };
+fz_error fz_kioneedin = { -1, "<ioneedin>", "<process>", "filter.c", 0 };
+fz_error fz_kioneedout = { -1, "<ioneedout>", "<process>", "filter.c", 0 };
+fz_error fz_kiodone = { -1, "<iodone>", "<process>", "filter.c", 0 };
 
 fz_error *
 fz_process(fz_filter *f, fz_buffer *in, fz_buffer *out)
@@ -31,11 +31,21 @@ fz_process(fz_filter *f, fz_buffer *in, fz_buffer *out)
 	return reason;
 }
 
+fz_filter *
+fz_keepfilter(fz_filter *f)
+{
+	f->nrefs ++;
+	return f;
+}
+
 void
 fz_dropfilter(fz_filter *f)
 {
-	if (f->drop)
-		f->drop(f);
-	fz_free(f);
+	if (--f->nrefs == 0)
+	{
+		if (f->drop)
+			f->drop(f);
+		fz_free(f);
+	}
 }
 
diff --git a/filter/pipeline.c b/filter/pipeline.c
index 4ac0da58..7b7f4252 100644
--- a/filter/pipeline.c
+++ b/filter/pipeline.c
@@ -19,10 +19,10 @@ fz_error *
 fz_chainpipeline(fz_filter **fp, fz_filter *head, fz_filter *tail, fz_buffer *buf)
 {
 	FZ_NEWFILTER(fz_pipeline, p, pipeline);
-	p->head = head;
-	p->tail = tail;
+	p->head = fz_keepfilter(head);
+	p->tail = fz_keepfilter(tail);
 	p->tailneedsin = 1;
-	p->buffer = buf;
+	p->buffer = fz_keepbuffer(buf);
 	return nil;
 }
 
@@ -30,24 +30,25 @@ void
 fz_unchainpipeline(fz_filter *filter, fz_filter **oldfp, fz_buffer **oldbp)
 {
 	fz_pipeline *p = (fz_pipeline*)filter;
-	*oldfp = p->head;
-	*oldbp = p->buffer;
-	fz_dropfilter(p->tail);
-	fz_free(p);
+
+	*oldfp = fz_keepfilter(p->head);
+	*oldbp = fz_keepbuffer(p->buffer);
+
+	fz_dropfilter(filter);
 }
 
 fz_error *
 fz_newpipeline(fz_filter **fp, fz_filter *head, fz_filter *tail)
 {
-	fz_error *err;
+	fz_error *error;
 
 	FZ_NEWFILTER(fz_pipeline, p, pipeline);
-	p->head = head;
-	p->tail = tail;
+	p->head = fz_keepfilter(head);
+	p->tail = fz_keepfilter(tail);
 	p->tailneedsin = 1;
 
-	err = fz_newbuffer(&p->buffer, FZ_BUFSIZE);
-	if (err) { fz_free(p); return err; }
+	error = fz_newbuffer(&p->buffer, FZ_BUFSIZE);
+	if (error) { fz_free(p); return error; }
 
 	return nil;
 }