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>

1 files changed, 13 insertions, 1 deletions

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());