Add unit test to feed valid SVG sequences to make sure that

path strings can be parsed without returning an error.

Draw the output through Skia and SVG to make sure they are
parsed correctly.

R=fmalita@chromium.org
BUG=skia:4549
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1675053002

Review URL: https://codereview.chromium.org/1675053002

1 files changed, 26 insertions, 23 deletions

diff --git a/src/utils/SkParsePath.cpp b/src/utils/SkParsePath.cpp
index c0f39aa06f..8baa6611ee 100644
--- a/src/utils/SkParsePath.cpp
+++ b/src/utils/SkParsePath.cpp
@@ -40,7 +40,9 @@ static const char* skip_ws(const char str[]) {
 }
 
 static const char* skip_sep(const char str[]) {
-    SkASSERT(str);
+    if (!str) {
+        return nullptr;
+    }
     while (is_sep(*str))
         str++;
     return str;
@@ -61,6 +63,9 @@ static const char* find_points(const char str[], SkPoint value[], int count,
 static const char* find_scalar(const char str[], SkScalar* value,
                                bool isRelative, SkScalar relative) {
     str = SkParse::FindScalar(str, value);
+    if (!str) {
+        return nullptr;
+    }
     if (isRelative) {
         *value += relative;
     }
@@ -70,7 +75,7 @@ static const char* find_scalar(const char str[], SkScalar* value,
 
 bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
     SkPath path;
-    SkPoint f = {0, 0};
+    SkPoint first = {0, 0};
     SkPoint c = {0, 0};
     SkPoint lastc = {0, 0};
     SkPoint points[3];
@@ -107,6 +112,7 @@ bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
             case 'M':
                 data = find_points(data, points, 1, relative, &c);
                 path.moveTo(points[0]);
+                previousOp = '\0';
                 op = 'L';
                 c = points[0];
                 break;
@@ -147,10 +153,10 @@ bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
                 goto quadraticCommon;
             case 'T':
                 data = find_points(data, &points[1], 1, relative, &c);
-                points[0] = points[1];
+                points[0] = c;
                 if (previousOp == 'Q' || previousOp == 'T') {
-                    points[0].fX = c.fX * 2 - lastc.fX;
-                    points[0].fY = c.fY * 2 - lastc.fY;
+                    points[0].fX -= lastc.fX - c.fX;
+                    points[0].fY -= lastc.fY - c.fY;
                 }
             quadraticCommon:
                 path.quadTo(points[0], points[1]);
@@ -159,27 +165,24 @@ bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
                 break;
             case 'A': {
                 SkPoint radii;
-                data = find_points(data, &radii, 1, false, nullptr);
                 SkScalar angle, largeArc, sweep;
-                data = find_scalar(data, &angle, false, 0);
-                data = find_scalar(data, &largeArc, false, 0);
-                data = find_scalar(data, &sweep, false, 0);
-                data = find_points(data, &points[0], 1, relative, &c);
-                path.arcTo(radii, angle, (SkPath::ArcSize) SkToBool(largeArc),
-                        (SkPath::Direction) !SkToBool(sweep), points[0]);
+                if ((data = find_points(data, &radii, 1, false, nullptr))
+                        && (data = skip_sep(data))
+                        && (data = find_scalar(data, &angle, false, 0))
+                        && (data = skip_sep(data))
+                        && (data = find_scalar(data, &largeArc, false, 0))
+                        && (data = skip_sep(data))
+                        && (data = find_scalar(data, &sweep, false, 0))
+                        && (data = skip_sep(data))
+                        && (data = find_points(data, &points[0], 1, relative, &c))) {
+                    path.arcTo(radii, angle, (SkPath::ArcSize) SkToBool(largeArc),
+                            (SkPath::Direction) !SkToBool(sweep), points[0]);
+                    path.getLastPt(&c);
+                }
                 } break;
             case 'Z':
                 path.close();
-#if 0   // !!! still a bug?
-                if (fPath.isEmpty() && (f.fX != 0 || f.fY != 0)) {
-                    c.fX -= SkScalar.Epsilon;   // !!! enough?
-                    fPath.moveTo(c);
-                    fPath.lineTo(f);
-                    fPath.close();
-                }
-#endif
-                c = f;
-                op = '\0';
+                c = first;
                 break;
             case '~': {
                 SkPoint args[2];
@@ -191,7 +194,7 @@ bool SkParsePath::FromSVGString(const char data[], SkPath* result) {
                 return false;
         }
         if (previousOp == 0) {
-            f = c;
+            first = c;
         }
         previousOp = op;
     }