From 2b4a96702789a5f59fe468a7be907ccd18071cec Mon Sep 17 00:00:00 2001
From: Sebastian Rasmussen <sebras@gmail.com>
Date: Fri, 7 Sep 2018 15:48:58 +0800
Subject: Bug 699743: Pop clip upon error when flushing text.

Not popping causes assert to be triggered in fz_draw_end_group().
---
 source/pdf/pdf-op-run.c | 89 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 81 insertions(+), 8 deletions(-)

diff --git a/source/pdf/pdf-op-run.c b/source/pdf/pdf-op-run.c
index cce39cf7..09fc4e23 100644
--- a/source/pdf/pdf-op-run.c
+++ b/source/pdf/pdf-op-run.c
@@ -823,6 +823,14 @@ pdf_flush_text(fz_context *ctx, pdf_run_processor *pr)
 	int doinvisible;
 	softmask_save softmask = { NULL };
 	int knockout_group = 0;
+	int innerclip = 0;
+	fz_rect tb;
+	char errmess[256] = "";
+	int err = FZ_ERROR_NONE;
+
+	fz_var(innerclip);
+	fz_var(knockout_group);
+	fz_var(tb);
 
 	text = pdf_tos_get_text(ctx, &pr->tos);
 	if (!text)
@@ -844,9 +852,10 @@ pdf_flush_text(fz_context *ctx, pdf_run_processor *pr)
 	if (pr->super.hidden)
 		dostroke = dofill = 0;
 
+	tb = fz_transform_rect(pr->tos.text_bbox, gstate->ctm);
+
 	fz_try(ctx)
 	{
-		fz_rect tb = fz_transform_rect(pr->tos.text_bbox, gstate->ctm);
 		if (dostroke)
 			tb = fz_adjust_rect_for_stroke(ctx, tb, gstate->stroke_state, gstate->ctm);
 
@@ -892,17 +901,21 @@ pdf_flush_text(fz_context *ctx, pdf_run_processor *pr)
 				if (gstate->fill.pattern)
 				{
 					fz_clip_text(ctx, pr->dev, text, gstate->ctm, tb);
+					innerclip = 1;
 					gstate = pdf_show_pattern(ctx, pr, gstate->fill.pattern, gstate->fill.gstate_num, tb, PDF_FILL);
 					fz_pop_clip(ctx, pr->dev);
+					innerclip = 0;
 				}
 				break;
 			case PDF_MAT_SHADE:
 				if (gstate->fill.shade)
 				{
 					fz_clip_text(ctx, pr->dev, text, gstate->ctm, tb);
+					innerclip = 1;
 					/* Page 2 of patterns.pdf shows that fz_fill_shade should NOT be called with gstate->ctm */
 					fz_fill_shade(ctx, pr->dev, gstate->fill.shade, pr->gstate[gstate->fill.gstate_num].ctm, gstate->fill.alpha, &gstate->fill.color_params);
 					fz_pop_clip(ctx, pr->dev);
+					innerclip = 0;
 				}
 				break;
 			}
@@ -922,35 +935,91 @@ pdf_flush_text(fz_context *ctx, pdf_run_processor *pr)
 				if (gstate->stroke.pattern)
 				{
 					fz_clip_stroke_text(ctx, pr->dev, text, gstate->stroke_state, gstate->ctm, tb);
+					innerclip = 1;
 					gstate = pdf_show_pattern(ctx, pr, gstate->stroke.pattern, gstate->stroke.gstate_num, tb, PDF_STROKE);
 					fz_pop_clip(ctx, pr->dev);
+					innerclip = 0;
 				}
 				break;
 			case PDF_MAT_SHADE:
 				if (gstate->stroke.shade)
 				{
 					fz_clip_stroke_text(ctx, pr->dev, text, gstate->stroke_state, gstate->ctm, tb);
+					innerclip = 1;
 					fz_fill_shade(ctx, pr->dev, gstate->stroke.shade, pr->gstate[gstate->stroke.gstate_num].ctm, gstate->stroke.alpha, &gstate->stroke.color_params);
 					fz_pop_clip(ctx, pr->dev);
+					innerclip = 0;
 				}
 				break;
 			}
 		}
 
+	}
+	fz_always(ctx)
+	{
+		if (innerclip)
+		{
+			fz_try(ctx)
+			{
+				fz_pop_clip(ctx, pr->dev);
+			}
+			fz_catch(ctx)
+			{
+				/* Postpone the problem */
+				err = fz_caught(ctx);
+				strcpy(errmess, fz_caught_message(ctx));
+			}
+		}
+
 		if (knockout_group)
-			fz_end_group(ctx, pr->dev);
+		{
+			fz_try(ctx)
+			{
+				fz_end_group(ctx, pr->dev);
+			}
+			fz_catch(ctx)
+			{
+				/* Postpone the problem */
+				if (err)
+					fz_warn(ctx, "ignoring error: %s", fz_caught_message(ctx));
+				err = fz_caught(ctx);
+				strcpy(errmess, fz_caught_message(ctx));
+			}
+		}
 
 		if (dofill || dostroke)
-			pdf_end_group(ctx, pr, &softmask);
+		{
+			fz_try(ctx)
+			{
+				pdf_end_group(ctx, pr, &softmask);
+			}
+			fz_catch(ctx)
+			{
+				/* Postpone the problem */
+				if (err)
+					fz_warn(ctx, "ignoring error: %s", fz_caught_message(ctx));
+				err = fz_caught(ctx);
+				strcpy(errmess, fz_caught_message(ctx));
+			}
+		}
 
 		if (doclip)
 		{
-			gstate->clip_depth++;
-			fz_clip_text(ctx, pr->dev, text, gstate->ctm, tb);
+			fz_try(ctx)
+			{
+				gstate->clip_depth++;
+				fz_clip_text(ctx, pr->dev, text, gstate->ctm, tb);
+			}
+			fz_catch(ctx)
+			{
+				/* Postpone the problem */
+				if (err)
+					fz_warn(ctx, "ignoring error: %s", fz_caught_message(ctx));
+				err = fz_caught(ctx);
+				strcpy(errmess, fz_caught_message(ctx));
+			}
 		}
-	}
-	fz_always(ctx)
-	{
+
 		fz_drop_text(ctx, text);
 	}
 	fz_catch(ctx)
@@ -958,6 +1027,10 @@ pdf_flush_text(fz_context *ctx, pdf_run_processor *pr)
 		fz_rethrow(ctx);
 	}
 
+	/* Rethrow postponed errors */
+	if (err)
+		fz_throw(ctx, err, "%s", errmess);
+
 	return pr->gstate + pr->gtop;
 }
 
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