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

3 files changed, 54 insertions, 29 deletions

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);
+}