1 files changed, 221 insertions, 0 deletions
diff --git a/source/pdf/pdf-clean-file.c b/source/pdf/pdf-clean-file.c
new file mode 100644
index 00000000..d224dd9a
--- /dev/null
+++ b/source/pdf/pdf-clean-file.c
@@ -0,0 +1,221 @@
+#include "mupdf/pdf.h"
+
+typedef struct globals_s
+{
+	pdf_document *doc;
+	fz_context *ctx;
+} globals;
+
+static int
+string_in_names_list(fz_context *ctx, pdf_obj *p, pdf_obj *names_list)
+{
+	int n = pdf_array_len(ctx, names_list);
+	int i;
+	char *str = pdf_to_str_buf(ctx, p);
+
+	for (i = 0; i < n ; i += 2)
+	{
+		if (!strcmp(pdf_to_str_buf(ctx, pdf_array_get(ctx, names_list, i)), str))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Recreate page tree to only retain specified pages.
+ */
+
+static void retainpage(fz_context *ctx, pdf_document *doc, pdf_obj *parent, pdf_obj *kids, int page)
+{
+	pdf_obj *pageref = pdf_lookup_page_obj(ctx, doc, page-1);
+	pdf_obj *pageobj = pdf_resolve_indirect(ctx, pageref);
+
+	pdf_dict_put(ctx, pageobj, PDF_NAME_Parent, parent);
+
+	/* Store page object in new kids array */
+	pdf_array_push(ctx, kids, pageref);
+}
+
+static void retainpages(fz_context *ctx, globals *glo, int argc, char **argv)
+{
+	pdf_obj *oldroot, *root, *pages, *kids, *countobj, *parent, *olddests;
+	pdf_document *doc = glo->doc;
+	int argidx = 0;
+	pdf_obj *names_list = NULL;
+	int pagecount;
+	int i;
+
+	/* Keep only pages/type and (reduced) dest entries to avoid
+	 * references to unretained pages */
+	oldroot = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root);
+	pages = pdf_dict_get(ctx, oldroot, PDF_NAME_Pages);
+	olddests = pdf_load_name_tree(ctx, doc, PDF_NAME_Dests);
+
+	root = pdf_new_dict(ctx, doc, 2);
+	pdf_dict_put(ctx, root, PDF_NAME_Type, pdf_dict_get(ctx, oldroot, PDF_NAME_Type));
+	pdf_dict_put(ctx, root, PDF_NAME_Pages, pdf_dict_get(ctx, oldroot, PDF_NAME_Pages));
+
+	pdf_update_object(ctx, doc, pdf_to_num(ctx, oldroot), root);
+
+	pdf_drop_obj(ctx, root);
+
+	/* Create a new kids array with only the pages we want to keep */
+	parent = pdf_new_indirect(ctx, doc, pdf_to_num(ctx, pages), pdf_to_gen(ctx, pages));
+	kids = pdf_new_array(ctx, doc, 1);
+
+	/* Retain pages specified */
+	while (argc - argidx)
+	{
+		int page, spage, epage;
+		char *spec, *dash;
+		char *pagelist = argv[argidx];
+
+		pagecount = pdf_count_pages(ctx, doc);
+		spec = fz_strsep(&pagelist, ",");
+		while (spec)
+		{
+			dash = strchr(spec, '-');
+
+			if (dash == spec)
+				spage = epage = pagecount;
+			else
+				spage = epage = atoi(spec);
+
+			if (dash)
+			{
+				if (strlen(dash) > 1)
+					epage = atoi(dash + 1);
+				else
+					epage = pagecount;
+			}
+
+			spage = fz_clampi(spage, 1, pagecount);
+			epage = fz_clampi(epage, 1, pagecount);
+
+			if (spage < epage)
+				for (page = spage; page <= epage; ++page)
+					retainpage(ctx, doc, parent, kids, page);
+			else
+				for (page = spage; page >= epage; --page)
+					retainpage(ctx, doc, parent, kids, page);
+
+			spec = fz_strsep(&pagelist, ",");
+		}
+
+		argidx++;
+	}
+
+	pdf_drop_obj(ctx, parent);
+
+	/* Update page count and kids array */
+	countobj = pdf_new_int(ctx, doc, pdf_array_len(ctx, kids));
+	pdf_dict_put(ctx, pages, PDF_NAME_Count, countobj);
+	pdf_drop_obj(ctx, countobj);
+	pdf_dict_put(ctx, pages, PDF_NAME_Kids, kids);
+	pdf_drop_obj(ctx, kids);
+
+	/* Also preserve the (partial) Dests name tree */
+	if (olddests)
+	{
+		pdf_obj *names = pdf_new_dict(ctx, doc, 1);
+		pdf_obj *dests = pdf_new_dict(ctx, doc, 1);
+		int len = pdf_dict_len(ctx, olddests);
+
+		names_list = pdf_new_array(ctx, doc, 32);
+
+		for (i = 0; i < len; i++)
+		{
+			pdf_obj *key = pdf_dict_get_key(ctx, olddests, i);
+			pdf_obj *val = pdf_dict_get_val(ctx, olddests, i);
+			pdf_obj *dest = pdf_dict_get(ctx, val, PDF_NAME_D);
+
+			dest = pdf_array_get(ctx, dest ? dest : val, 0);
+			if (pdf_array_contains(ctx, pdf_dict_get(ctx, pages, PDF_NAME_Kids), dest))
+			{
+				pdf_obj *key_str = pdf_new_string(ctx, doc, pdf_to_name(ctx, key), strlen(pdf_to_name(ctx, key)));
+				pdf_array_push(ctx, names_list, key_str);
+				pdf_array_push(ctx, names_list, val);
+				pdf_drop_obj(ctx, key_str);
+			}
+		}
+
+		root = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root);
+		pdf_dict_put(ctx, dests, PDF_NAME_Names, names_list);
+		pdf_dict_put(ctx, names, PDF_NAME_Dests, dests);
+		pdf_dict_put(ctx, root, PDF_NAME_Names, names);
+
+		pdf_drop_obj(ctx, names);
+		pdf_drop_obj(ctx, dests);
+		pdf_drop_obj(ctx, names_list);
+		pdf_drop_obj(ctx, olddests);
+	}
+
+	/* Force the next call to pdf_count_pages to recount */
+	glo->doc->page_count = 0;
+
+	/* Edit each pages /Annot list to remove any links that point to
+	 * nowhere. */
+	pagecount = pdf_count_pages(ctx, doc);
+	for (i = 0; i < pagecount; i++)
+	{
+		pdf_obj *pageref = pdf_lookup_page_obj(ctx, doc, i);
+		pdf_obj *pageobj = pdf_resolve_indirect(ctx, pageref);
+
+		pdf_obj *annots = pdf_dict_get(ctx, pageobj, PDF_NAME_Annots);
+
+		int len = pdf_array_len(ctx, annots);
+		int j;
+
+		for (j = 0; j < len; j++)
+		{
+			pdf_obj *o = pdf_array_get(ctx, annots, j);
+			pdf_obj *p;
+
+			if (!pdf_name_eq(ctx, pdf_dict_get(ctx, o, PDF_NAME_Subtype), PDF_NAME_Link))
+				continue;
+
+			p = pdf_dict_get(ctx, o, PDF_NAME_A);
+			if (!pdf_name_eq(ctx, pdf_dict_get(ctx, p, PDF_NAME_S), PDF_NAME_GoTo))
+				continue;
+
+			if (string_in_names_list(ctx, pdf_dict_get(ctx, p, PDF_NAME_D), names_list))
+				continue;
+
+			/* FIXME: Should probably look at Next too */
+
+			/* Remove this annotation */
+			pdf_array_delete(ctx, annots, j);
+			j--;
+		}
+	}
+}
+
+void pdf_clean_file(fz_context *ctx, char *infile, char *outfile, char *password, fz_write_options *opts, char *argv[], int argc)
+{
+	globals glo = { 0 };
+
+	glo.ctx = ctx;
+
+	fz_try(ctx)
+	{
+		glo.doc = pdf_open_document_no_run(ctx, infile);
+		if (pdf_needs_password(ctx, glo.doc))
+			if (!pdf_authenticate_password(ctx, glo.doc, password))
+				fz_throw(glo.ctx, FZ_ERROR_GENERIC, "cannot authenticate password: %s", infile);
+
+		/* Only retain the specified subset of the pages */
+		if (argc)
+			retainpages(ctx, &glo, argc, argv);
+
+		pdf_write_document(ctx, glo.doc, outfile, opts);
+	}
+	fz_always(ctx)
+	{
+		pdf_close_document(ctx, glo.doc);
+	}
+	fz_catch(ctx)
+	{
+		if (opts && opts->errors)
+			*opts->errors = *opts->errors+1;
+	}
+}