check for bad enum use when adding contours

Review URL: https://codereview.appspot.com/6849103

git-svn-id: http://skia.googlecode.com/svn/trunk@6547 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 81 insertions, 50 deletions

diff --git a/include/core/SkPath.h b/include/core/SkPath.h
index cea964c177..942342dd56 100644
--- a/include/core/SkPath.h
+++ b/include/core/SkPath.h
@@ -510,9 +510,15 @@ public:
         kCCW_Direction,
     };
 
+    /**
+     *  Return the opposite of the specified direction. kUnknown is its own
+     *  opposite.
+     */
     static Direction OppositeDirection(Direction dir) {
-        static const Direction kOppositeDir[] = {kUnknown_Direction, kCCW_Direction, kCW_Direction};
-        return kOppositeDir[dir];
+        static const Direction gOppositeDir[] = {
+            kUnknown_Direction, kCCW_Direction, kCW_Direction
+        };
+        return gOppositeDir[dir];
     }
 
     /**
@@ -527,12 +533,13 @@ public:
     /**
      *  Returns true if the path's direction can be computed via
      *  cheapComputDirection() and if that computed direction matches the
-     *  specified direction.
+     *  specified direction. If dir is kUnknown, returns true if the direction
+     *  cannot be computed.
      */
     bool cheapIsDirection(Direction dir) const {
-        SkASSERT(kCW_Direction == dir || kCCW_Direction == dir);
-        Direction computedDir;
-        return this->cheapComputeDirection(&computedDir) && computedDir == dir;
+        Direction computedDir = kUnknown_Direction;
+        (void)this->cheapComputeDirection(&computedDir);
+        return computedDir == dir;
     }
 
     /** Returns true if the path specifies a rectangle. If so, and if isClosed is
@@ -546,44 +553,52 @@ public:
     */
     bool isRect(bool* isClosed, Direction* direction) const;
 
-    /** Add a closed rectangle contour to the path
-        @param rect The rectangle to add as a closed contour to the path
-        @param dir  The direction to wind the rectangle's contour
-    */
+    /**
+     *  Add a closed rectangle contour to the path
+     *  @param rect The rectangle to add as a closed contour to the path
+     *  @param dir  The direction to wind the rectangle's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void    addRect(const SkRect& rect, Direction dir = kCW_Direction);
 
-    /** Add a closed rectangle contour to the path
-
-        @param left     The left side of a rectangle to add as a closed contour
-                        to the path
-        @param top      The top of a rectangle to add as a closed contour to the
-                        path
-        @param right    The right side of a rectangle to add as a closed contour
-                        to the path
-        @param bottom   The bottom of a rectangle to add as a closed contour to
-                        the path
-        @param dir      The direction to wind the rectangle's contour
-    */
+    /**
+     *  Add a closed rectangle contour to the path
+     *
+     *  @param left     The left side of a rectangle to add as a closed contour
+     *                  to the path
+     *  @param top      The top of a rectangle to add as a closed contour to the
+     *                  path
+     *  @param right    The right side of a rectangle to add as a closed contour
+     *                  to the path
+     *  @param bottom   The bottom of a rectangle to add as a closed contour to
+     *                  the path
+     *  @param dir  The direction to wind the rectangle's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void addRect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom,
                  Direction dir = kCW_Direction);
 
-    /** Add a closed oval contour to the path
-
-        @param oval The bounding oval to add as a closed contour to the path
-        @param dir  The direction to wind the oval's contour
-    */
+    /**
+     *  Add a closed oval contour to the path
+     *
+     *  @param oval The bounding oval to add as a closed contour to the path
+     *  @param dir  The direction to wind the oval's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void addOval(const SkRect& oval, Direction dir = kCW_Direction);
 
-    /** Add a closed circle contour to the path
-
-        @param x        The x-coordinate of the center of a circle to add as a
-                        closed contour to the path
-        @param y        The y-coordinate of the center of a circle to add as a
-                        closed contour to the path
-        @param radius   The radius of a circle to add as a closed contour to the
-                        path
-        @param dir      The direction to wind the circle's contour
-    */
+    /**
+     *  Add a closed circle contour to the path
+     *
+     *  @param x        The x-coordinate of the center of a circle to add as a
+     *                  closed contour to the path
+     *  @param y        The y-coordinate of the center of a circle to add as a
+     *                  closed contour to the path
+     *  @param radius   The radius of a circle to add as a closed contour to the
+     *                  path
+     *  @param dir  The direction to wind the circle's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void addCircle(SkScalar x, SkScalar y, SkScalar radius,
                    Direction dir = kCW_Direction);
 
@@ -595,22 +610,26 @@ public:
     */
     void addArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle);
 
-    /** Add a closed round-rectangle contour to the path
-        @param rect The bounds of a round-rectangle to add as a closed contour
-        @param rx   The x-radius of the rounded corners on the round-rectangle
-        @param ry   The y-radius of the rounded corners on the round-rectangle
-        @param dir  The direction to wind the round-rectangle's contour
-    */
+    /**
+     *  Add a closed round-rectangle contour to the path
+     *  @param rect The bounds of a round-rectangle to add as a closed contour
+     *  @param rx   The x-radius of the rounded corners on the round-rectangle
+     *  @param ry   The y-radius of the rounded corners on the round-rectangle
+     *  @param dir  The direction to wind the rectangle's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void    addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
                          Direction dir = kCW_Direction);
 
-    /** Add a closed round-rectangle contour to the path. Each corner receives
-        two radius values [X, Y]. The corners are ordered top-left, top-right,
-        bottom-right, bottom-left.
-        @param rect The bounds of a round-rectangle to add as a closed contour
-        @param radii Array of 8 scalars, 4 [X,Y] pairs for each corner
-        @param dir  The direction to wind the round-rectangle's contour
-        */
+    /**
+     *  Add a closed round-rectangle contour to the path. Each corner receives
+     *  two radius values [X, Y]. The corners are ordered top-left, top-right,
+     *  bottom-right, bottom-left.
+     *  @param rect The bounds of a round-rectangle to add as a closed contour
+     *  @param radii Array of 8 scalars, 4 [X,Y] pairs for each corner
+     *  @param dir  The direction to wind the rectangle's contour. Cannot be
+     *              kUnknown_Direction.
+     */
     void addRoundRect(const SkRect& rect, const SkScalar radii[],
                       Direction dir = kCW_Direction);
 
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index c3aa44e117..80ca3011e3 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -872,12 +872,17 @@ void SkPath::close() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+static void assert_known_direction(int dir) {
+    SkASSERT(SkPath::kCW_Direction == dir || SkPath::kCCW_Direction == dir);
+}
+
 void SkPath::addRect(const SkRect& rect, Direction dir) {
     this->addRect(rect.fLeft, rect.fTop, rect.fRight, rect.fBottom, dir);
 }
 
 void SkPath::addRect(SkScalar left, SkScalar top, SkScalar right,
                      SkScalar bottom, Direction dir) {
+    assert_known_direction(dir);
     fDirection = this->hasOnlyMoveTos() ? dir : kUnknown_Direction;
     SkAutoDisableDirectionCheck addc(this);
 
@@ -938,6 +943,8 @@ void SkPath::addPoly(const SkPoint pts[], int count, bool close) {
 
 void SkPath::addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
                           Direction dir) {
+    assert_known_direction(dir);
+
     SkScalar    w = rect.width();
     SkScalar    halfW = SkScalarHalf(w);
     SkScalar    h = rect.height();
@@ -1058,6 +1065,8 @@ static void add_corner_arc(SkPath* path, const SkRect& rect,
 
 void SkPath::addRoundRect(const SkRect& rect, const SkScalar rad[],
                           Direction dir) {
+    assert_known_direction(dir);
+
     // abort before we invoke SkAutoPathBoundsUpdate()
     if (rect.isEmpty()) {
         return;
@@ -1094,6 +1103,8 @@ bool SkPath::hasOnlyMoveTos() const {
 }
 
 void SkPath::addOval(const SkRect& oval, Direction dir) {
+    assert_known_direction(dir);
+
     /* If addOval() is called after previous moveTo(),
        this path is still marked as an oval. This is used to
        fit into WebKit's calling sequences.
diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index f1894c3940..6f9a9e6465 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -375,6 +375,7 @@ static void test_direction(skiatest::Reporter* reporter) {
     REPORTER_ASSERT(reporter, !path.cheapComputeDirection(NULL));
     REPORTER_ASSERT(reporter, !path.cheapIsDirection(SkPath::kCW_Direction));
     REPORTER_ASSERT(reporter, !path.cheapIsDirection(SkPath::kCCW_Direction));
+    REPORTER_ASSERT(reporter, path.cheapIsDirection(SkPath::kUnknown_Direction));
 
     static const char* gDegen[] = {
         "M 10 10",