Scanline decoding for wbmp

tests/CodexTest.cpp

Index: tests/CodexTest.cpp
diff --git a/tests/CodexTest.cpp b/tests/CodexTest.cpp
index 1dd64d9a6dacb5a6b4fa7b91721da6c39d84a057..b1ff6a9874a917ea9280e0b8c99b9c9610252795 100644
--- a/tests/CodexTest.cpp
+++ b/tests/CodexTest.cpp
@@ -152,7 +152,7 @@ static void check(skiatest::Reporter* r,
 
 DEF_TEST(Codec, r) {
     // WBMP
-    check(r, "mandrill.wbmp", SkISize::Make(512, 512), false, false);
+    check(r, "mandrill.wbmp", SkISize::Make(512, 512), true, false);
 
     // WEBP
     check(r, "baby_tux.webp", SkISize::Make(386, 395), false, true);
@@ -289,3 +289,23 @@ DEF_TEST(Codec_Empty, r) {
     test_empty(r, "empty_images/zero-width.wbmp");
     test_empty(r, "empty_images/zero-height.wbmp");
 }
+
+static void test_invalid_parameters(skiatest::Reporter* r, const char path[]) {
+    SkAutoTDelete<SkStream> stream(resource(path));
+    if (!stream) {
+        SkDebugf("Missing resource '%s'\n", path);
+        return;
+    }
+    SkAutoTDelete<SkScanlineDecoder> decoder(SkScanlineDecoder::NewFromStream(stream.detach()));
+    // This should return kInvalidConversion because, in kIndex_8 mode, we must pass in a valid
+    // colorPtr and a valid colorCountPtr.
+    SkCodec::Result result = decoder->start(
+        decoder->getInfo().makeColorType(kIndex_8_SkColorType), NULL, NULL, NULL);

[scroggo, 2015/08/04 20:24:11]

FWIW, you could leave off the last three NULLs and call the version that just
takes an SkImageInfo (or test both?)

[msarett, 2015/08/04 21:21:26]

I put the SkASSERT back in.  This means we will crash if try to test the other
version.

+    REPORTER_ASSERT(r, SkCodec::kInvalidConversion == result);
+}
+
+DEF_TEST(Codec_Params, r) {
+    test_invalid_parameters(r, "mandrill_512.png");

[scroggo, 2015/08/04 20:24:11]

Is this a kIndex8 image? It might be interesting to verify that this succeeds if
you pass a color table, but not if you do not.

(As a side note, maybe this should be kInvalidParameters, since it's not the
conversion that's the problem, but the fact that you did not supply a color
table.)

[msarett, 2015/08/04 21:21:26]

Yes kInvalidParameters is better!
Yes it is better to test kSuccess on passing a ctable and kInvalidParameters
when it is not passed in.

+    test_invalid_parameters(r, "mandrill.wbmp");
+    test_invalid_parameters(r, "CMYK.jpg");
+}