1 files changed, 121 insertions, 166 deletions

diff --git a/source/pdf/pdf-stream.c b/source/pdf/pdf-stream.c
index 34ffe7af..379ed504 100644
--- a/source/pdf/pdf-stream.c
+++ b/source/pdf/pdf-stream.c
@@ -158,116 +158,93 @@ static fz_stream *
 build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
 {
 	fz_compression_params local_params;
-	fz_stream *tmp;
 
-	fz_var(chain);
+	if (params == NULL)
+		params = &local_params;
 
-	fz_try(ctx)
-	{
-		if (params == NULL)
-			params = &local_params;
+	build_compression_params(ctx, f, p, params);
 
-		build_compression_params(ctx, f, p, params);
+	/* If we were using params we were passed in, and we successfully
+	 * recognised the image type, we can use the existing filter and
+	 * shortstop here. */
+	if (params != &local_params && params->type != FZ_IMAGE_RAW)
+		return fz_keep_stream(ctx, chain); /* nothing to do */
 
-		/* If we were using params we were passed in, and we successfully
-		 * recognised the image type, we can use the existing filter and
-		 * shortstop here. */
-		if (params != &local_params && params->type != FZ_IMAGE_RAW)
-			break; /* nothing to do */
+	else if (params->type != FZ_IMAGE_RAW)
+		return fz_open_image_decomp_stream(ctx, chain, params, NULL);
 
-		else if (params->type != FZ_IMAGE_RAW)
-		{
-			tmp = chain;
-			chain = NULL;
-			chain = fz_open_image_decomp_stream(ctx, tmp, params, NULL);
-		}
+	else if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
+		return fz_open_ahxd(ctx, chain);
 
-		else if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
-		{
-			tmp = chain;
-			chain = NULL;
-			chain = fz_open_ahxd(ctx, tmp);
-		}
-
-		else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
-		{
-			tmp = chain;
-			chain = NULL;
-			chain = fz_open_a85d(ctx, tmp);
-		}
+	else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
+		return fz_open_a85d(ctx, chain);
 
-		else if (pdf_name_eq(ctx, f, PDF_NAME_JBIG2Decode))
+	else if (pdf_name_eq(ctx, f, PDF_NAME_JBIG2Decode))
+	{
+		fz_jbig2_globals *globals = NULL;
+		pdf_obj *obj = pdf_dict_get(ctx, p, PDF_NAME_JBIG2Globals);
+		if (obj)
 		{
-			fz_jbig2_globals *globals = NULL;
-			pdf_obj *obj = pdf_dict_get(ctx, p, PDF_NAME_JBIG2Globals);
-			if (obj)
-			{
-				if (!pdf_is_stream(ctx, obj))
-					fz_warn(ctx, "jbig2 globals is not a stream, skipping globals");
-				else
-					globals = pdf_load_jbig2_globals(ctx, doc, obj);
-			}
-			tmp = chain;
-			chain = NULL;
-			chain = fz_open_jbig2d(ctx, tmp, globals);
+			if (!pdf_is_stream(ctx, obj))
+				fz_warn(ctx, "jbig2 globals is not a stream, skipping globals");
+			else
+				globals = pdf_load_jbig2_globals(ctx, doc, obj);
 		}
+		return fz_open_jbig2d(ctx, chain, globals); /* takes ownership of jbig2_globals */
+	}
 
-		else if (pdf_name_eq(ctx, f, PDF_NAME_JPXDecode))
-			break; /* JPX decoding is special cased in the image loading code */
+	else if (pdf_name_eq(ctx, f, PDF_NAME_JPXDecode))
+		return fz_keep_stream(ctx, chain); /* JPX decoding is special cased in the image loading code */
 
-		else if (pdf_name_eq(ctx, f, PDF_NAME_Crypt))
+	else if (pdf_name_eq(ctx, f, PDF_NAME_Crypt))
+	{
+		if (!doc->crypt)
+			fz_warn(ctx, "crypt filter in unencrypted document");
+		else
 		{
-			if (!doc->crypt)
-				fz_warn(ctx, "crypt filter in unencrypted document");
-			else
-			{
-				pdf_obj *name = pdf_dict_get(ctx, p, PDF_NAME_Name);
-				if (pdf_is_name(ctx, name))
-				{
-					tmp = chain;
-					chain = NULL;
-					chain = pdf_open_crypt_with_filter(ctx, tmp, doc->crypt, name, num, gen);
-				}
-			}
+			pdf_obj *name = pdf_dict_get(ctx, p, PDF_NAME_Name);
+			if (pdf_is_name(ctx, name))
+				return pdf_open_crypt_with_filter(ctx, chain, doc->crypt, name, num, gen);
 		}
-		else
-			fz_warn(ctx, "unknown filter name (%s)", pdf_to_name(ctx, f));
 	}
+
+	else
+		fz_warn(ctx, "unknown filter name (%s)", pdf_to_name(ctx, f));
+
+	return fz_keep_stream(ctx, chain);
+}
+
+/* Build filter, and assume ownership of chain */
+static fz_stream *
+build_filter_drop(fz_context *ctx, fz_stream *tail, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
+{
+	fz_stream *head;
+	fz_try(ctx)
+		head = build_filter(ctx, tail, doc, f, p, num, gen, params);
+	fz_always(ctx)
+		fz_drop_stream(ctx, tail);
 	fz_catch(ctx)
-	{
-		fz_drop_stream(ctx, chain);
 		fz_rethrow(ctx);
-	}
-
-	return chain;
+	return head;
 }
 
 /*
  * Build a chain of filters given filter names and param dicts.
- * If head is given, start filter chain with it.
- * Assume ownership of head.
+ * If chain is given, start filter chain with it.
+ * Assume ownership of chain.
  */
 static fz_stream *
-build_filter_chain(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *fs, pdf_obj *ps, int num, int gen, fz_compression_params *params)
+build_filter_chain_drop(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *fs, pdf_obj *ps, int num, int gen, fz_compression_params *params)
 {
-	pdf_obj *f;
-	pdf_obj *p;
-	int i, n;
-
 	fz_var(chain);
-
 	fz_try(ctx)
 	{
-		n = pdf_array_len(ctx, fs);
+		int i, n = pdf_array_len(ctx, fs);
 		for (i = 0; i < n; i++)
 		{
-			fz_stream *chain2;
-
-			f = pdf_array_get(ctx, fs, i);
-			p = pdf_array_get(ctx, ps, i);
-			chain2 = chain;
-			chain = NULL;
-			chain = build_filter(ctx, chain2, doc, f, p, num, gen, (i == n-1 ? params : NULL));
+			pdf_obj *f = pdf_array_get(ctx, fs, i);
+			pdf_obj *p = pdf_array_get(ctx, ps, i);
+			chain = build_filter_drop(ctx, chain, doc, f, p, num, gen, (i == n-1 ? params : NULL));
 		}
 	}
 	fz_catch(ctx)
@@ -275,10 +252,15 @@ build_filter_chain(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj
 		fz_drop_stream(ctx, chain);
 		fz_rethrow(ctx);
 	}
-
 	return chain;
 }
 
+static fz_stream *
+build_filter_chain(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *fs, pdf_obj *ps, int num, int gen, fz_compression_params *params)
+{
+	return build_filter_chain_drop(ctx, fz_keep_stream(ctx, chain), doc, fs, ps, num, gen, params);
+}
+
 /*
  * Build a filter for reading raw stream data.
  * This is a null filter to constrain reading to the stream length (and to
@@ -288,10 +270,10 @@ build_filter_chain(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj
  * orig_num and orig_gen are used purely to seed the encryption.
  */
 static fz_stream *
-pdf_open_raw_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *stmobj, int num, int *orig_num, int *orig_gen, int64_t offset)
+pdf_open_raw_filter(fz_context *ctx, fz_stream *file_stm, pdf_document *doc, pdf_obj *stmobj, int num, int *orig_num, int *orig_gen, int64_t offset)
 {
 	pdf_xref_entry *x = NULL;
-	fz_stream *chain2;
+	fz_stream *null_stm, *crypt_stm;
 	int hascrypt;
 	int len;
 
@@ -311,33 +293,20 @@ pdf_open_raw_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_ob
 		*orig_gen = 0;
 	}
 
-	chain = fz_keep_stream(ctx, chain);
-
-	fz_var(chain);
-
-	fz_try(ctx)
+	hascrypt = pdf_stream_has_crypt(ctx, stmobj);
+	len = pdf_to_int(ctx, pdf_dict_get(ctx, stmobj, PDF_NAME_Length));
+	null_stm = fz_open_null(ctx, file_stm, len, offset);
+	if (doc->crypt && !hascrypt)
 	{
-		len = pdf_to_int(ctx, pdf_dict_get(ctx, stmobj, PDF_NAME_Length));
-
-		chain2 = chain;
-		chain = NULL;
-		chain = fz_open_null(ctx, chain2, len, offset);
-
-		hascrypt = pdf_stream_has_crypt(ctx, stmobj);
-		if (doc->crypt && !hascrypt)
-		{
-			chain2 = chain;
-			chain = NULL;
-			chain = pdf_open_crypt(ctx, chain2, doc->crypt, *orig_num, *orig_gen);
-		}
-	}
-	fz_catch(ctx)
-	{
-		fz_drop_stream(ctx, chain);
-		fz_rethrow(ctx);
+		fz_try(ctx)
+			crypt_stm = pdf_open_crypt(ctx, null_stm, doc->crypt, *orig_num, *orig_gen);
+		fz_always(ctx)
+			fz_drop_stream(ctx, null_stm);
+		fz_catch(ctx)
+			fz_rethrow(ctx);
+		return crypt_stm;
 	}
-
-	return chain;
+	return null_stm;
 }
 
 /*
@@ -345,41 +314,29 @@ pdf_open_raw_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_ob
  * to stream length and decrypting.
  */
 static fz_stream *
-pdf_open_filter(fz_context *ctx, pdf_document *doc, fz_stream *chain, pdf_obj *stmobj, int num, int64_t offset, fz_compression_params *imparams)
+pdf_open_filter(fz_context *ctx, pdf_document *doc, fz_stream *file_stm, pdf_obj *stmobj, int num, int64_t offset, fz_compression_params *imparams)
 {
-	pdf_obj *filters;
-	pdf_obj *params;
+	pdf_obj *filters = pdf_dict_geta(ctx, stmobj, PDF_NAME_Filter, PDF_NAME_F);
+	pdf_obj *params = pdf_dict_geta(ctx, stmobj, PDF_NAME_DecodeParms, PDF_NAME_DP);
 	int orig_num, orig_gen;
+	fz_stream *rstm, *fstm;
 
-	filters = pdf_dict_geta(ctx, stmobj, PDF_NAME_Filter, PDF_NAME_F);
-	params = pdf_dict_geta(ctx, stmobj, PDF_NAME_DecodeParms, PDF_NAME_DP);
-
-	chain = pdf_open_raw_filter(ctx, chain, doc, stmobj, num, &orig_num, &orig_gen, offset);
-
-	fz_var(chain);
-
+	rstm = pdf_open_raw_filter(ctx, file_stm, doc, stmobj, num, &orig_num, &orig_gen, offset);
 	fz_try(ctx)
 	{
 		if (pdf_is_name(ctx, filters))
-		{
-			fz_stream *chain2 = chain;
-			chain = NULL;
-			chain = build_filter(ctx, chain2, doc, filters, params, orig_num, orig_gen, imparams);
-		}
+			fstm = build_filter(ctx, rstm, doc, filters, params, orig_num, orig_gen, imparams);
 		else if (pdf_array_len(ctx, filters) > 0)
-		{
-			fz_stream *chain2 = chain;
-			chain = NULL;
-			chain = build_filter_chain(ctx, chain2, doc, filters, params, orig_num, orig_gen, imparams);
-		}
+			fstm = build_filter_chain(ctx, rstm, doc, filters, params, orig_num, orig_gen, imparams);
+		else
+			fstm = fz_keep_stream(ctx, rstm);
 	}
+	fz_always(ctx)
+		fz_drop_stream(ctx, rstm);
 	fz_catch(ctx)
-	{
-		fz_drop_stream(ctx, chain);
 		fz_rethrow(ctx);
-	}
 
-	return chain;
+	return fstm;
 }
 
 /*
@@ -387,54 +344,52 @@ pdf_open_filter(fz_context *ctx, pdf_document *doc, fz_stream *chain, pdf_obj *s
  * constraining to stream length, and without decryption.
  */
 fz_stream *
-pdf_open_inline_stream(fz_context *ctx, pdf_document *doc, pdf_obj *stmobj, int length, fz_stream *chain, fz_compression_params *imparams)
+pdf_open_inline_stream(fz_context *ctx, pdf_document *doc, pdf_obj *stmobj, int length, fz_stream *file_stm, fz_compression_params *imparams)
 {
-	pdf_obj *filters;
-	pdf_obj *params;
-	int64_t offset;
-
-	filters = pdf_dict_geta(ctx, stmobj, PDF_NAME_Filter, PDF_NAME_F);
-	params = pdf_dict_geta(ctx, stmobj, PDF_NAME_DecodeParms, PDF_NAME_DP);
-
-	/* don't close chain when we close this filter */
-	fz_keep_stream(ctx, chain);
+	pdf_obj *filters = pdf_dict_geta(ctx, stmobj, PDF_NAME_Filter, PDF_NAME_F);
+	pdf_obj *params = pdf_dict_geta(ctx, stmobj, PDF_NAME_DecodeParms, PDF_NAME_DP);
 
 	if (pdf_is_name(ctx, filters))
-		return build_filter(ctx, chain, doc, filters, params, 0, 0, imparams);
-	if (pdf_array_len(ctx, filters) > 0)
-		return build_filter_chain(ctx, chain, doc, filters, params, 0, 0, imparams);
+		return build_filter(ctx, file_stm, doc, filters, params, 0, 0, imparams);
+	else if (pdf_array_len(ctx, filters) > 0)
+		return build_filter_chain(ctx, file_stm, doc, filters, params, 0, 0, imparams);
 
 	if (imparams)
 		imparams->type = FZ_IMAGE_RAW;
-
-	fz_try(ctx)
-		offset = fz_tell(ctx, chain);
-	fz_catch(ctx)
-	{
-		fz_drop_stream(ctx, chain);
-		fz_rethrow(ctx);
-	}
-
-	return fz_open_null(ctx, chain, length, offset);
+	return fz_open_null(ctx, file_stm, length, fz_tell(ctx, file_stm));
 }
 
 void
-pdf_load_compressed_inline_image(fz_context *ctx, pdf_document *doc, pdf_obj *dict, int length, fz_stream *stm, int indexed, fz_compressed_image *image)
+pdf_load_compressed_inline_image(fz_context *ctx, pdf_document *doc, pdf_obj *dict, int length, fz_stream *file_stm, int indexed, fz_compressed_image *image)
 {
-	fz_compressed_buffer *bc = fz_malloc_struct(ctx, fz_compressed_buffer);
+	fz_stream *istm, *leech, *decomp;
+	fz_pixmap *pixmap;
+	fz_compressed_buffer *bc;
+	int dummy_l2factor = 0;
 
+	fz_var(istm);
+	fz_var(leech);
+	fz_var(decomp);
+	fz_var(pixmap);
+
+	bc = fz_malloc_struct(ctx, fz_compressed_buffer);
 	fz_try(ctx)
 	{
-		int dummy_l2factor = 0;
 		bc->buffer = fz_new_buffer(ctx, 1024);
-
-		stm = pdf_open_inline_stream(ctx, doc, dict, length, stm, &bc->params);
-		stm = fz_open_leecher(ctx, stm, bc->buffer);
-		stm = fz_open_image_decomp_stream(ctx, stm, &bc->params, &dummy_l2factor);
-
-		fz_set_compressed_image_tile(ctx, image, fz_decomp_image_from_stream(ctx, stm, image, NULL, indexed, 0));
+		istm = pdf_open_inline_stream(ctx, doc, dict, length, file_stm, &bc->params);
+		leech = fz_open_leecher(ctx, istm, bc->buffer);
+		decomp = fz_open_image_decomp_stream(ctx, leech, &bc->params, &dummy_l2factor);
+		pixmap = fz_decomp_image_from_stream(ctx, leech, image, NULL, indexed, 0);
+		fz_set_compressed_image_tile(ctx, image, pixmap);
 		fz_set_compressed_image_buffer(ctx, image, bc);
 	}
+	fz_always(ctx)
+	{
+		fz_drop_stream(ctx, istm);
+		fz_drop_stream(ctx, leech);
+		fz_drop_stream(ctx, decomp);
+		fz_drop_pixmap(ctx, pixmap);
+	}
 	fz_catch(ctx)
 	{
 		fz_drop_compressed_buffer(ctx, bc);