Tweak API fuzzers to run better in libfuzzer

Prevents logging from cluttering the stats.
Better handles limited memory.

Bug: skia:
Change-Id: I12c1a46875fd9120938cab520ef70de69c451ad8
Reviewed-on: https://skia-review.googlesource.com/110642
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Kevin Lubick <kjlubick@google.com>

4 files changed, 35 insertions, 17 deletions

diff --git a/fuzz/Fuzz.h b/fuzz/Fuzz.h
index 221b8f87bf..a7771713cf 100644
--- a/fuzz/Fuzz.h
+++ b/fuzz/Fuzz.h
@@ -109,6 +109,7 @@ inline void Fuzz::nextRange(T* n, Min min, Max max) {
     }
     if (min > max) {
         // Avoid misuse of nextRange
+        SkDebugf("min > max (%d > %d) \n", min, max);
         this->signalBug();
     }
     if (*n < 0) { // Handle negatives
diff --git a/fuzz/FuzzCanvas.cpp b/fuzz/FuzzCanvas.cpp
index 9e117af66f..42e31b6a4e 100644
--- a/fuzz/FuzzCanvas.cpp
+++ b/fuzz/FuzzCanvas.cpp
@@ -901,7 +901,10 @@ static SkBitmap make_fuzz_bitmap(Fuzz* fuzz) {
     int w, h;
     fuzz->nextRange(&w, 1, 1024);
     fuzz->nextRange(&h, 1, 1024);
-    bitmap.allocN32Pixels(w, h);
+    if (!bitmap.tryAllocN32Pixels(w, h)) {
+        SkDEBUGF(("Could not allocate pixels %d x %d", w, h));
+        return bitmap;
+    }
     for (int y = 0; y < h; ++y) {
         for (int x = 0; x < w; ++x) {
             SkColor c;
@@ -973,6 +976,11 @@ static SkTDArray<uint8_t> make_fuzz_text(Fuzz* fuzz, const SkPaint& paint) {
     if (SkPaint::kGlyphID_TextEncoding == paint.getTextEncoding()) {
         int glyphRange = paint.getTypeface() ? paint.getTypeface()->countGlyphs()
                                              : SkTypeface::MakeDefault()->countGlyphs();
+        if (glyphRange == 0) {
+            // Some fuzzing environments have no fonts, so empty array is the best
+            // we can do.
+            return array;
+        }
         int glyphCount;
         fuzz->nextRange(&glyphCount, 1, kMaxGlyphCount);
         SkGlyphID* glyphs = (SkGlyphID*)array.append(glyphCount * sizeof(SkGlyphID));
@@ -1464,6 +1472,10 @@ static void fuzz_canvas(Fuzz* fuzz, SkCanvas* canvas, int depth = 9) {
                 if (make_fuzz_t<bool>(fuzz)) {
                     fuzz->next(&center);
                 } else {  // Make valid center, see SkLatticeIter::Valid().
+                    if (img.width() == 0 || img.height() == 0) {
+                        // bitmap may not have had its pixels initialized.
+                        break;
+                    }
                     fuzz->nextRange(&center.fLeft, 0, img.width() - 1);
                     fuzz->nextRange(&center.fTop, 0, img.height() - 1);
                     fuzz->nextRange(&center.fRight, center.fLeft + 1, img.width());
diff --git a/fuzz/FuzzDrawFunctions.cpp b/fuzz/FuzzDrawFunctions.cpp
index 5029ebe967..15443fdd85 100644
--- a/fuzz/FuzzDrawFunctions.cpp
+++ b/fuzz/FuzzDrawFunctions.cpp
@@ -81,7 +81,7 @@ static void init_bitmap(Fuzz* fuzz, SkBitmap* bmp) {
                                          (SkColorType)colorType,
                                          b ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
     if (!bmp->tryAllocPixels(info)) {
-        SkDebugf("Bitmap not allocated\n");
+        SkDEBUGF(("Bitmap not allocated\n"));
     }
     SkColor c;
     fuzz->next(&c);
@@ -103,6 +103,11 @@ static void init_surface(Fuzz* fuzz, sk_sp<SkSurface>* s) {
     fuzz->nextRange(&x, 1, kMaxX);
     fuzz->nextRange(&y, 1, kMaxY);
     *s = SkSurface::MakeRasterN32Premul(x, y);
+
+    if (!*s) {
+        // Was possibly too big for the memory constrained fuzzing environments
+        *s = SkSurface::MakeNull(x, y);
+    }
 }
 
 
@@ -313,36 +318,36 @@ DEF_FUZZ(DrawFunctions, fuzz) {
               SkDebugf("Could not initialize font.\n");
               fuzz->signalBug();
             }
-            SkDebugf("Fuzz DrawText\n");
+            SkDEBUGF(("Fuzz DrawText\n"));
             fuzz_drawText(fuzz, f);
             return;
         }
         case 1:
-            SkDebugf("Fuzz DrawRect\n");
+            SkDEBUGF(("Fuzz DrawRect\n"));
             fuzz_drawRect(fuzz);
             return;
         case 2:
-            SkDebugf("Fuzz DrawCircle\n");
+            SkDEBUGF(("Fuzz DrawCircle\n"));
             fuzz_drawCircle(fuzz);
             return;
         case 3:
-            SkDebugf("Fuzz DrawLine\n");
+            SkDEBUGF(("Fuzz DrawLine\n"));
             fuzz_drawLine(fuzz);
             return;
         case 4:
-            SkDebugf("Fuzz DrawPath\n");
+            SkDEBUGF(("Fuzz DrawPath\n"));
             fuzz_drawPath(fuzz);
             return;
         case 5:
-            SkDebugf("Fuzz DrawImage/DrawImageRect\n");
+            SkDEBUGF(("Fuzz DrawImage/DrawImageRect\n"));
             fuzz_drawImage(fuzz);
             return;
         case 6:
-            SkDebugf("Fuzz DrawBitmap\n");
+            SkDEBUGF(("Fuzz DrawBitmap\n"));
             fuzz_drawBitmap(fuzz);
             return;
         case 7:
-            SkDebugf("Fuzz DrawPaint\n");
+            SkDEBUGF(("Fuzz DrawPaint\n"));
             fuzz_drawPaint(fuzz);
             return;
     }
diff --git a/fuzz/FuzzGradients.cpp b/fuzz/FuzzGradients.cpp
index 88f3429d50..1c06af52bf 100644
--- a/fuzz/FuzzGradients.cpp
+++ b/fuzz/FuzzGradients.cpp
@@ -56,11 +56,11 @@ static void logOptionalMatrix(const char* label, const SkMatrix* m) {
         return;
     }
 
-    SkDebugf("  %s: [ ", label);
+    SkDEBUGF(("  %s: [ ", label));
     for (int i = 0; i < 9; ++i) {
-        SkDebugf("%.9g ", m->get(i));
+        SkDEBUGF(("%.9g ", m->get(i)));
     }
-    SkDebugf("]\n");
+    SkDEBUGF(("]\n"));
 }
 
 static void logLinearGradient(const SkPoint pts[2],
@@ -256,19 +256,19 @@ DEF_FUZZ(Gradients, fuzz) {
 
     switch(i) {
         case 0:
-            SkDebugf("LinearGradient\n");
+            SkDEBUGF(("LinearGradient\n"));
             fuzzLinearGradient(fuzz);
             return;
         case 1:
-            SkDebugf("RadialGradient\n");
+            SkDEBUGF(("RadialGradient\n"));
             fuzzRadialGradient(fuzz);
             return;
         case 2:
-            SkDebugf("TwoPointConicalGradient\n");
+            SkDEBUGF(("TwoPointConicalGradient\n"));
             fuzzTwoPointConicalGradient(fuzz);
             return;
     }
-    SkDebugf("SweepGradient\n");
+    SkDEBUGF(("SweepGradient\n"));
     fuzzSweepGradient(fuzz);
     return;
 }