Merge branch 'issue907' into 'master'

Fix invalid pdf generation with too many objects in object stream

See merge request cairo/cairo!642

src/cairo-pdf-surface.c

@@ -2310,44 +2310,6 @@ _cairo_pdf_surface_open_object_stream (cairo_pdf_surface_t *surface)
     return _cairo_output_stream_get_status (surface->object_stream.stream);
 }
 
-cairo_int_status_t
-_cairo_pdf_surface_object_begin (cairo_pdf_surface_t *surface,
-				 cairo_pdf_resource_t resource)
-{
-    cairo_xref_stream_object_t xref_obj;
-    cairo_pdf_object_t *object;
-    cairo_int_status_t status;
-
-    if (surface->object_stream.active) {
-	xref_obj.resource = resource;
-	xref_obj.offset = _cairo_output_stream_get_position (surface->object_stream.stream);
-	status = _cairo_array_append (&surface->object_stream.objects, &xref_obj);
-	if (unlikely (status))
-	    return status;
-
-	object = _cairo_array_index (&surface->objects, resource.id - 1);
-	object->type = PDF_OBJECT_COMPRESSED;
-	object->u.compressed_obj.xref_stream = surface->object_stream.resource;
-	object->u.compressed_obj.index = _cairo_array_num_elements (&surface->object_stream.objects) - 1;
-
-    } else {
-	_cairo_pdf_surface_update_object (surface, resource);
-	_cairo_output_stream_printf (surface->output,
-				     "%d 0 obj\n",
-				     resource.id);
-    }
-    return CAIRO_INT_STATUS_SUCCESS;
-}
-
-void
-_cairo_pdf_surface_object_end (cairo_pdf_surface_t *surface)
-{
-    if (!surface->object_stream.active) {
-	_cairo_output_stream_printf (surface->output,
-				     "endobj\n");
-    }
-}
-
 static int
 _cairo_xref_stream_object_compare (const void *a,
 				   const void *b)
@@ -2467,6 +2429,58 @@ _cairo_pdf_surface_close_object_stream (cairo_pdf_surface_t *surface)
     return _cairo_output_stream_get_status (surface->output);
 }
 
+cairo_int_status_t
+_cairo_pdf_surface_object_begin (cairo_pdf_surface_t *surface,
+				 cairo_pdf_resource_t resource)
+{
+    cairo_xref_stream_object_t xref_obj;
+    cairo_pdf_object_t *object;
+    cairo_int_status_t status;
+	int num_objects;
+
+    if (surface->object_stream.active) {
+	num_objects = _cairo_array_num_elements (&surface->object_stream.objects);
+    if (unlikely (num_objects == 65536)) {
+	// In the XRef table, the generation number is stored as a 16-bit integer.
+	// Therefore, we can only have 65536 objects in a single object stream.
+	// Close the current object stream and open a new one.
+	status = _cairo_pdf_surface_close_object_stream(surface);
+	if (unlikely (status))
+	    return status;
+	status = _cairo_pdf_surface_open_object_stream(surface);
+	if (unlikely (status))
+	    return status;
+	}
+
+	xref_obj.resource = resource;
+	xref_obj.offset = _cairo_output_stream_get_position (surface->object_stream.stream);
+	status = _cairo_array_append (&surface->object_stream.objects, &xref_obj);
+	if (unlikely (status))
+	    return status;
+
+	object = _cairo_array_index (&surface->objects, resource.id - 1);
+	object->type = PDF_OBJECT_COMPRESSED;
+	object->u.compressed_obj.xref_stream = surface->object_stream.resource;
+	object->u.compressed_obj.index = _cairo_array_num_elements (&surface->object_stream.objects) - 1;
+
+    } else {
+	_cairo_pdf_surface_update_object (surface, resource);
+	_cairo_output_stream_printf (surface->output,
+				     "%d 0 obj\n",
+				     resource.id);
+    }
+    return CAIRO_INT_STATUS_SUCCESS;
+}
+
+void
+_cairo_pdf_surface_object_end (cairo_pdf_surface_t *surface)
+{
+    if (!surface->object_stream.active) {
+	_cairo_output_stream_printf (surface->output,
+				     "endobj\n");
+    }
+}
+
 static cairo_int_status_t
 _cairo_pdf_surface_open_content_stream (cairo_pdf_surface_t       *surface,
 					const cairo_box_double_t  *bbox,

test/meson.build

@@ -452,6 +452,7 @@ test_quartz_sources = [
 
 test_pdf_sources = [
   'pdf-features.c',
+  'pdf-large-objstm.c',
   'pdf-mime-data.c',
   'pdf-operators-text.c',
   'pdf-surface-source.c',

test/pdf-large-objstm.c

@@ -0,0 +1,178 @@
+/*
+ * Copyright © 2023 Adrian Johnson
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Adrian Johnson <ajohnson@redneon.com>
+ */
+
+#include "cairo-test.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+#ifdef HAVE_MMAP
+#include <sys/mman.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h> /* __unix__ */
+#endif
+#if HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+
+#include <cairo.h>
+#include <cairo-pdf.h>
+
+/* Test PDF with a large number of objects to ensure that
+ * object streams are correctly handled.
+ */
+
+#define BASENAME "pdf-large-objstm"
+
+static void
+draw_link(cairo_t *cr)
+{
+    cairo_tag_begin(cr, CAIRO_TAG_LINK, "uri='http://www.mozilla.org/'");
+    cairo_move_to (cr, 0, 0);
+    cairo_show_text (cr, "a");
+    cairo_tag_end(cr, CAIRO_TAG_LINK);
+}
+
+#ifdef HAVE_MMAP
+static cairo_test_status_t
+check_contains_string(cairo_test_context_t *ctx, const void *hay, size_t size, const char *needle)
+{
+    if (memmem(hay, size, needle, strlen(needle)))
+        return CAIRO_TEST_SUCCESS;
+
+    cairo_test_log (ctx, "Failed to find expected string in generated PDF: %s\n", needle);
+    return CAIRO_TEST_FAILURE;
+}
+#endif
+
+static cairo_test_status_t
+check_created_pdf(cairo_test_context_t *ctx, const char* filename)
+{
+    cairo_test_status_t result = CAIRO_TEST_SUCCESS;
+    int fd;
+    struct stat st;
+#ifdef HAVE_MMAP
+    void *contents;
+#endif
+
+    fd = open(filename, O_RDONLY, 0);
+    if (fd < 0) {
+        cairo_test_log (ctx, "Failed to open generated PDF file %s: %s\n", filename, strerror(errno));
+        return CAIRO_TEST_FAILURE;
+    }
+
+    if (fstat(fd, &st) == -1)
+    {
+        cairo_test_log (ctx, "Failed to stat generated PDF file %s: %s\n", filename, strerror(errno));
+        close(fd);
+        return CAIRO_TEST_FAILURE;
+    }
+
+    if (st.st_size == 0)
+    {
+        cairo_test_log (ctx, "Generated PDF file %s is empty\n", filename);
+        close(fd);
+        return CAIRO_TEST_FAILURE;
+    }
+
+#ifdef HAVE_MMAP
+
+    printf("Checking generated PDF file %s\n", filename);
+
+    contents = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (contents == NULL)
+    {
+        cairo_test_log (ctx, "Failed to mmap generated PDF file %s: %s\n", filename, strerror(errno));
+        close(fd);
+        return CAIRO_TEST_FAILURE;
+    }
+
+    /* check metadata */
+    result |= check_contains_string(ctx, contents, st.st_size, "/N 65536");
+    result |= check_contains_string(ctx, contents, st.st_size, "/N 14470");
+
+    munmap(contents, st.st_size);
+#endif
+
+    close(fd);
+
+    return result;
+}
+
+static cairo_test_status_t
+create_pdf (cairo_test_context_t *ctx)
+{
+    cairo_surface_t *surface;
+    cairo_t *cr;
+    cairo_test_status_t result;
+    char *filename;
+    const char *path = cairo_test_mkdir (CAIRO_TEST_OUTPUT_DIR) ? CAIRO_TEST_OUTPUT_DIR : ".";
+
+    xasprintf (&filename, "%s/%s.pdf", path, BASENAME);
+    surface = cairo_pdf_surface_create (filename, 100, 100);
+    cr = cairo_create(surface);
+
+    for (int i = 0; i < 40000; i++) {
+        draw_link(cr);
+    }
+
+    cairo_show_page (cr);
+
+    cairo_surface_destroy (surface);
+    cairo_destroy (cr);
+
+    result = check_created_pdf(ctx, filename);
+
+    free (filename);
+
+    return result;
+}
+
+static cairo_test_status_t
+preamble (cairo_test_context_t *ctx)
+{
+    cairo_test_status_t result;
+
+    if (! cairo_test_is_target_enabled (ctx, "pdf"))
+	return CAIRO_TEST_UNTESTED;
+
+    result = create_pdf (ctx);
+
+    return result;
+}
+
+CAIRO_TEST (pdf_large_objstm,
+	    "Test with a lot of PDF objects",
+	    "source", /* keywords */
+	    NULL, /* requirements */
+	    100, 100,
+	    preamble, NULL)