Accept image/jpg for compatibility reasons

https://bugs.webkit.org/show_bug.cgi?id=246131 rdar://100835192 Reviewed by Said Abou-Hallawa and Darin Adler. Blink & Gecko seem to render JPEG images served with `Content-Type: image/jpg` while WebKit decides to download it because the correct content type is supposed to be `image/jpeg`. This is an interoperability risk so we should align. In this patch, we now treat `image/jpg` as a valid JPEG content type to align with other browser engines. Also revert a couple of unintended changes that were made in 237163@main: - The logic in normalizedImageMIMEType() was for CURL only but the condition got mistakenly reversed. - The normalized MIME type was previously used for both supportedImageMIMETypeSet and additionalSupportedImageMIMETypes. However, 237163@main stopped using the normalized MIME type for supportedImageMIMETypeSet. * LayoutTests/http/tests/images/jpg-invalid-content-type-expected.html: Added. * LayoutTests/http/tests/images/jpg-invalid-content-type.html: Added. * Source/WebCore/platform/MIMETypeRegistry.cpp: (WebCore::MIMETypeRegistry::isSupportedImageMIMEType): Canonical link: https://commits.webkit.org/255268@main
WebKit · Oct 7, 2022 · 0d17dc0c310f9b1d05268ab63e967c38133892f0 · 0d17dc0
1 parent 05f0430
commit 0d17dc0c310f9b1d05268ab63e967c38133892f0
Show file tree

Hide file tree

Showing 4 changed files with 34 additions and 6 deletions.
diff --git a/LayoutTests/http/tests/images/jpg-invalid-content-type-expected.html b/LayoutTests/http/tests/images/jpg-invalid-content-type-expected.html
@@ -0,0 +1,7 @@
+<DOCTYPE html>
+<html>
+<body>
+<p>Tests that a JPEG image served with `Content-Type: image/jpg` gets rendered, and not downloaded.</p>
+<iframe id="testFrame" src="/resources/square20.jpg"></iframe>
+</body>
+</html>
diff --git a/LayoutTests/http/tests/images/jpg-invalid-content-type.html b/LayoutTests/http/tests/images/jpg-invalid-content-type.html
@@ -0,0 +1,18 @@
+<DOCTYPE html>
+<html>
+<body>
+<p>Tests that a JPEG image served with `Content-Type: image/jpg` gets rendered, and not downloaded.</p>
+<iframe id="testFrame" src="about:blank"></iframe>
+<script>
+if (window.testRunner)
+    testRunner.waitUntilDone();
+
+let testFrame = document.getElementById("testFrame");
+testFrame.src = "/resources/load-and-stall.py?name=square20.jpg&mimeType=image%2Fjpg";
+testFrame.onload = () => {
+    if (window.testRunner)
+        testRunner.notifyDone();
+};
+</script>
+</body>
+</html>
diff --git a/Source/WebCore/platform/MIMETypeRegistry.cpp b/Source/WebCore/platform/MIMETypeRegistry.cpp
@@ -113,6 +113,7 @@ constexpr ComparableCaseFoldingASCIILiteral supportedImageMIMETypeArray[] = {
 #if !USE(CG) && USE(OPENJPEG)
     "image/jpeg2000",
 #endif
+    "image/jpg",
 #if USE(JPEGXL)
     "image/jxl",
 #endif
@@ -422,9 +423,11 @@ bool MIMETypeRegistry::isSupportedImageMIMEType(const String& mimeType)
         }
     });
 #endif
-    if (supportedImageMIMETypeSet.contains(mimeType))
+
+    String normalizedMIMEType = normalizedImageMIMEType(mimeType);
+    if (supportedImageMIMETypeSet.contains(normalizedMIMEType))
         return true;
-    return additionalSupportedImageMIMETypes().contains(normalizedImageMIMEType(mimeType));
+    return additionalSupportedImageMIMETypes().contains(normalizedMIMEType);
 }
 
 bool MIMETypeRegistry::isSupportedImageVideoOrSVGMIMEType(const String& mimeType)
@@ -715,8 +718,6 @@ bool MIMETypeRegistry::isSupportedModelMIMEType(const String& mimeType)
 static String normalizedImageMIMEType(const String& mimeType)
 {
 #if USE(CURL)
-    return mimeType;
-#else
     // FIXME: Since this is only used in isSupportedImageMIMEType, we should consider removing the non-image types below.
     static constexpr std::pair<ComparableLettersLiteral, ASCIILiteral> mimeTypeAssociationArray[] = {
         { "application/ico", "image/vnd.microsoft.icon"_s },
@@ -769,6 +770,8 @@ static String normalizedImageMIMEType(const String& mimeType)
     static constexpr SortedArrayMap associationMap { mimeTypeAssociationArray };
     auto normalizedType = associationMap.tryGet(mimeType);
     return normalizedType ? *normalizedType : mimeType;
+#else
+    return mimeType;
 #endif
 }
 
@@ -845,7 +848,7 @@ bool MIMETypeRegistry::isJPEGMIMEType(const String& mimeType)
         return false;
     return CFEqual(destinationUTI.get(), jpegUTI());
 #else
-    return mimeType == "image/jpeg"_s;
+    return mimeType == "image/jpeg"_s || mimeType == "image/jpg"_s;
 #endif
 }
 

diff --git a/Source/WebCore/platform/graphics/cg/ImageBufferUtilitiesCG.cpp b/Source/WebCore/platform/graphics/cg/ImageBufferUtilitiesCG.cpp
@@ -85,7 +85,7 @@ ALLOW_DEPRECATED_DECLARATIONS_BEGIN
 
     if (equalLettersIgnoringASCIICase(mimeType, "image/png"_s))
         return kUTTypePNG;
-    if (equalLettersIgnoringASCIICase(mimeType, "image/jpeg"_s))
+    if (equalLettersIgnoringASCIICase(mimeType, "image/jpeg"_s) || equalLettersIgnoringASCIICase(mimeType, "image/jpg"_s))
         return jpegUTI();
     if (equalLettersIgnoringASCIICase(mimeType, "image/gif"_s))
         return kUTTypeGIF;