Bug 1656099 - AVIF (AV1 Image File Format): sniff MIME type from content. r=aosmond

Differential Revision: https://phabricator.services.mozilla.com/D85503

image/imgLoader.cpp

@@ -51,6 +51,7 @@
 #include "nsIProgressEventSink.h"
 #include "nsIProtocolHandler.h"
 #include "nsImageModule.h"
+#include "nsMediaSniffer.h"
 #include "nsMimeTypes.h"
 #include "nsNetCID.h"
 #include "nsNetUtil.h"
@@ -2782,6 +2783,9 @@ nsresult imgLoader::GetMimeTypeFromContent(const char* aContents,
              !memcmp(aContents + 8, "WEBP", 4)) {
     aContentType.AssignLiteral(IMAGE_WEBP);
 
+  } else if (MatchesMP4(reinterpret_cast<const uint8_t*>(aContents), aLength,
+                        aContentType)) {
+    MOZ_ASSERT(aContentType.Equals(IMAGE_AVIF));
   } else {
     /* none of the above?  I give up */
     return NS_ERROR_NOT_AVAILABLE;

image/test/gtest/TestLoader.cpp

@@ -67,6 +67,26 @@ TEST_F(ImageLoader, DetectWebP) {
   CheckMimeType(buffer, sizeof(buffer), IMAGE_WEBP);
 }
 
+TEST_F(ImageLoader, DetectAVIFMajorBrand) {
+  const char buffer[] =
+      "\x00\x00\x00\x20"   // box length
+      "ftyp"               // box type
+      "avif"               // major brand
+      "\x00\x00\x00\x00"   // minor version
+      "avifmif1miafMA1B";  // compatible brands
+  CheckMimeType(buffer, sizeof(buffer), IMAGE_AVIF);
+}
+
+TEST_F(ImageLoader, DetectAVIFCompatibleBrand) {
+  const char buffer[] =
+      "\x00\x00\x00\x20"   // box length
+      "ftyp"               // box type
+      "XXXX"               // major brand
+      "\x00\x00\x00\x00"   // minor version
+      "avifmif1miafMA1B";  // compatible brands
+  CheckMimeType(buffer, sizeof(buffer), IMAGE_AVIF);
+}
+
 TEST_F(ImageLoader, DetectNone) {
   const char buffer[] = "abcdefghijklmnop";
   CheckMimeType(buffer, sizeof(buffer), nullptr);

toolkit/components/mediasniffer/nsMediaSniffer.cpp

@@ -57,6 +57,7 @@ nsMediaSnifferEntry sFtypEntries[] = {
     PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "qt  ", VIDEO_QUICKTIME),
     PATTERN_ENTRY("\xFF\xFF\xFF", "iso", VIDEO_MP4),  // Could be isom or iso2.
     PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "mmp4", VIDEO_MP4),
+    PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "avif", IMAGE_AVIF),
 };
 
 static bool MatchesBrands(const uint8_t aData[4], nsACString& aSniffedType) {
@@ -84,8 +85,8 @@ static bool MatchesBrands(const uint8_t aData[4], nsACString& aSniffedType) {
 // including MP4 (described at
 // http://mimesniff.spec.whatwg.org/#signature-for-mp4), M4A (Apple iTunes
 // audio), and 3GPP.
-static bool MatchesMP4(const uint8_t* aData, const uint32_t aLength,
-                       nsACString& aSniffedType) {
+bool MatchesMP4(const uint8_t* aData, const uint32_t aLength,
+                nsACString& aSniffedType) {
   if (aLength <= MP4_MIN_BYTES_COUNT) {
     return false;
   }

toolkit/components/mediasniffer/nsMediaSniffer.h

@@ -33,6 +33,9 @@ struct nsMediaSnifferEntry {
   const char* mContentType;
 };
 
+bool MatchesMP4(const uint8_t* aData, const uint32_t aLength,
+                nsACString& aSniffedType);
+
 class nsMediaSniffer final : public nsIContentSniffer {
  public:
   NS_DECL_ISUPPORTS