fix misc asserts and checks found by fuzzer

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1719993002

Review URL: https://codereview.chromium.org/1719993002

8 files changed, 84 insertions, 45 deletions

diff --git a/include/core/SkPathEffect.h b/include/core/SkPathEffect.h
index bd68c8fa72..a77b9467e4 100644
--- a/include/core/SkPathEffect.h
+++ b/include/core/SkPathEffect.h
@@ -183,7 +183,13 @@ public:
         The reference counts for outer and inner are both incremented in the constructor,
         and decremented in the destructor.
     */
-    static SkComposePathEffect* Create(SkPathEffect* outer, SkPathEffect* inner) {
+    static SkPathEffect* Create(SkPathEffect* outer, SkPathEffect* inner) {
+        if (!outer) {
+            return SkSafeRef(inner);
+        }
+        if (!inner) {
+            return SkSafeRef(outer);
+        }
         return new SkComposePathEffect(outer, inner);
     }
 
@@ -220,7 +226,13 @@ public:
         The reference counts for first and second are both incremented in the constructor,
         and decremented in the destructor.
     */
-    static SkSumPathEffect* Create(SkPathEffect* first, SkPathEffect* second) {
+    static SkPathEffect* Create(SkPathEffect* first, SkPathEffect* second) {
+        if (!first) {
+            return SkSafeRef(second);
+        }
+        if (!second) {
+            return SkSafeRef(first);
+        }
         return new SkSumPathEffect(first, second);
     }
 
diff --git a/include/effects/Sk1DPathEffect.h b/include/effects/Sk1DPathEffect.h
index 3419dc23b7..03c6966943 100644
--- a/include/effects/Sk1DPathEffect.h
+++ b/include/effects/Sk1DPathEffect.h
@@ -46,7 +46,7 @@ public:
         kRotate_Style,      // rotate the shape about its center
         kMorph_Style,       // transform each point, and turn lines into curves
 
-        kStyleCount
+        kLastEnum_Style = kMorph_Style,
     };
 
     /** Dash by replicating the specified path.
@@ -56,9 +56,7 @@ public:
         @param style how to transform path at each point (based on the current
                      position and tangent)
     */
-    static SkPathEffect* Create(const SkPath& path, SkScalar advance, SkScalar phase, Style style) {
-        return new SkPath1DPathEffect(path, advance, phase, style);
-    }
+    static SkPathEffect* Create(const SkPath& path, SkScalar advance, SkScalar phase, Style);
 
     virtual bool filterPath(SkPath*, const SkPath&,
                             SkStrokeRec*, const SkRect*) const override;
diff --git a/include/effects/SkAlphaThresholdFilter.h b/include/effects/SkAlphaThresholdFilter.h
index 17521b6455..033e8d1e54 100644
--- a/include/effects/SkAlphaThresholdFilter.h
+++ b/include/effects/SkAlphaThresholdFilter.h
@@ -20,8 +20,8 @@ public:
      * The 0,0 point of the region corresponds to the upper left corner of the
      * source image.
      */
-    static SkImageFilter* Create(const SkRegion& region, SkScalar innerThreshold,
-                                 SkScalar outerThreshold, SkImageFilter* input = NULL);
+    static SkImageFilter* Create(const SkRegion& region, SkScalar innerMin,
+                                 SkScalar outerMax, SkImageFilter* input = NULL);
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP();
 };
 
diff --git a/include/effects/SkDashPathEffect.h b/include/effects/SkDashPathEffect.h
index 3c1407b725..08b0a4693f 100644
--- a/include/effects/SkDashPathEffect.h
+++ b/include/effects/SkDashPathEffect.h
@@ -36,10 +36,7 @@ public:
 
         Note: only affects stroked paths.
     */
-    static SkPathEffect* Create(const SkScalar intervals[], int count, SkScalar phase) {
-        return new SkDashPathEffect(intervals, count, phase);
-    }
-    virtual ~SkDashPathEffect();
+    static SkPathEffect* Create(const SkScalar intervals[], int count, SkScalar phase);
 
     virtual bool filterPath(SkPath* dst, const SkPath& src,
                             SkStrokeRec*, const SkRect*) const override;
@@ -58,6 +55,7 @@ public:
 #endif
 
 protected:
+    virtual ~SkDashPathEffect();
     SkDashPathEffect(const SkScalar intervals[], int count, SkScalar phase);
     void flatten(SkWriteBuffer&) const override;
 
@@ -66,6 +64,7 @@ private:
     int32_t     fCount;
     SkScalar    fPhase;
     // computed from phase
+
     SkScalar    fInitialDashLength;
     int32_t     fInitialDashIndex;
     SkScalar    fIntervalLength;
diff --git a/samplecode/SampleFilterFuzz.cpp b/samplecode/SampleFilterFuzz.cpp
index f8ceed452c..687921ae0b 100644
--- a/samplecode/SampleFilterFuzz.cpp
+++ b/samplecode/SampleFilterFuzz.cpp
@@ -204,7 +204,7 @@ static SkTypeface::Style make_typeface_style() {
 }
 
 static SkPath1DPathEffect::Style make_path_1d_path_effect_style() {
-    return static_cast<SkPath1DPathEffect::Style>(R(SkPath1DPathEffect::kStyleCount));
+    return static_cast<SkPath1DPathEffect::Style>(R((int)SkPath1DPathEffect::kLastEnum_Style + 1));
 }
 
 static SkColor make_color() {
@@ -527,9 +527,14 @@ static SkPaint make_paint() {
     paint.setXfermodeMode(make_xfermode());
     paint.setPathEffect(make_path_effect());
     paint.setMaskFilter(make_mask_filter());
-    SkAutoTUnref<SkTypeface> typeface(
-        SkTypeface::CreateFromName(make_font_name().c_str(), make_typeface_style()));
-    paint.setTypeface(typeface);
+
+    if (false) {
+        // our validating buffer does not support typefaces yet, so skip this for now
+        SkAutoTUnref<SkTypeface> typeface(
+                      SkTypeface::CreateFromName(make_font_name().c_str(), make_typeface_style()));
+        paint.setTypeface(typeface);
+    }
+
     SkLayerRasterizer::Builder rasterizerBuilder;
     SkPaint paintForRasterizer;
     if (R(2) == 1) {
diff --git a/src/effects/Sk1DPathEffect.cpp b/src/effects/Sk1DPathEffect.cpp
index 041886e1db..4be6f975d3 100644
--- a/src/effects/Sk1DPathEffect.cpp
+++ b/src/effects/Sk1DPathEffect.cpp
@@ -35,39 +35,33 @@ bool Sk1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
 SkPath1DPathEffect::SkPath1DPathEffect(const SkPath& path, SkScalar advance,
     SkScalar phase, Style style) : fPath(path)
 {
-    if (advance <= 0 || path.isEmpty()) {
-        SkDEBUGF(("SkPath1DPathEffect can't use advance <= 0\n"));
-        fAdvance = 0;   // signals we can't draw anything
-        fInitialOffset = 0;
-        fStyle = kStyleCount;
-    } else {
-        // cleanup their phase parameter, inverting it so that it becomes an
-        // offset along the path (to match the interpretation in PostScript)
-        if (phase < 0) {
-            phase = -phase;
-            if (phase > advance) {
-                phase = SkScalarMod(phase, advance);
-            }
-        } else {
-            if (phase > advance) {
-                phase = SkScalarMod(phase, advance);
-            }
-            phase = advance - phase;
+    SkASSERT(advance > 0 && !path.isEmpty());
+    // cleanup their phase parameter, inverting it so that it becomes an
+    // offset along the path (to match the interpretation in PostScript)
+    if (phase < 0) {
+        phase = -phase;
+        if (phase > advance) {
+            phase = SkScalarMod(phase, advance);
         }
-        // now catch the edge case where phase == advance (within epsilon)
-        if (phase >= advance) {
-            phase = 0;
+    } else {
+        if (phase > advance) {
+            phase = SkScalarMod(phase, advance);
         }
-        SkASSERT(phase >= 0);
+        phase = advance - phase;
+    }
+    // now catch the edge case where phase == advance (within epsilon)
+    if (phase >= advance) {
+        phase = 0;
+    }
+    SkASSERT(phase >= 0);
 
-        fAdvance = advance;
-        fInitialOffset = phase;
+    fAdvance = advance;
+    fInitialOffset = phase;
 
-        if ((unsigned)style >= kStyleCount) {
-            SkDEBUGF(("SkPath1DPathEffect style enum out of range %d\n", style));
-        }
-        fStyle = style;
+    if ((unsigned)style > kMorph_Style) {
+        SkDEBUGF(("SkPath1DPathEffect style enum out of range %d\n", style));
     }
+    fStyle = style;
 }
 
 bool SkPath1DPathEffect::filterPath(SkPath* dst, const SkPath& src,
@@ -207,3 +201,13 @@ void SkPath1DPathEffect::toString(SkString* str) const {
     str->appendf(")");
 }
 #endif
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+SkPathEffect* SkPath1DPathEffect::Create(const SkPath& path, SkScalar advance, SkScalar phase,
+                                         Style style) {
+    if (advance <= 0 || path.isEmpty()) {
+        return nullptr;
+    }
+    return new SkPath1DPathEffect(path, advance, phase, style);
+}
diff --git a/src/effects/SkAlphaThresholdFilter.cpp b/src/effects/SkAlphaThresholdFilter.cpp
index 79520602b7..d3d36f7630 100644
--- a/src/effects/SkAlphaThresholdFilter.cpp
+++ b/src/effects/SkAlphaThresholdFilter.cpp
@@ -45,11 +45,19 @@ SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkAlphaThresholdFilter)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkAlphaThresholdFilterImpl)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
 
+static SkScalar pin_0_1(SkScalar x) {
+    return SkMinScalar(SkMaxScalar(x, 0), 1);
+}
 
 SkImageFilter* SkAlphaThresholdFilter::Create(const SkRegion& region,
                                               SkScalar innerThreshold,
                                               SkScalar outerThreshold,
                                               SkImageFilter* input) {
+    innerThreshold = pin_0_1(innerThreshold);
+    outerThreshold = pin_0_1(outerThreshold);
+    if (!SkScalarIsFinite(innerThreshold) || !SkScalarIsFinite(outerThreshold)) {
+        return nullptr;
+    }
     return new SkAlphaThresholdFilterImpl(region, innerThreshold, outerThreshold, input);
 }
 
@@ -334,7 +342,6 @@ void SkAlphaThresholdFilterImpl::flatten(SkWriteBuffer& buffer) const {
 bool SkAlphaThresholdFilterImpl::onFilterImageDeprecated(Proxy* proxy, const SkBitmap& src,
                                                          const Context& ctx, SkBitmap* dst,
                                                          SkIPoint* offset) const {
-    SkASSERT(src.colorType() == kN32_SkColorType);
 
     if (src.colorType() != kN32_SkColorType) {
         return false;
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
index 6e10e5466d..ced0aab69a 100644
--- a/src/effects/SkDashPathEffect.cpp
+++ b/src/effects/SkDashPathEffect.cpp
@@ -384,3 +384,17 @@ void SkDashPathEffect::toString(SkString* str) const {
     str->appendf("))");
 }
 #endif
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+SkPathEffect* SkDashPathEffect::Create(const SkScalar intervals[], int count, SkScalar phase) {
+    if ((count < 2) || !SkIsAlign2(count)) {
+        return nullptr;
+    }
+    for (int i = 0; i < count; i++) {
+        if (intervals[i] < 0) {
+            return nullptr;
+        }
+    }
+    return new SkDashPathEffect(intervals, count, phase);
+}