#1037 use truncated preview when opening large DNG with metadata extractor

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/MetadataFetchHandler.kt

@@ -296,7 +296,7 @@ class MetadataFetchHandler(private val context: Context) : MethodCallHandler {
                                                 byGeoTiff[false]?.map { exifTagMapper(it) }?.let { dirMap.putAll(it) }
                                             }
 
-                                            mimeType == MimeTypes.DNG -> {
+                                            mimeType == MimeTypes.DNG || mimeType == MimeTypes.DNG_ADOBE -> {
                                                 // split DNG tags in their own directory
                                                 val dngDirMap = metadataMap[DIR_DNG] ?: HashMap()
                                                 metadataMap[DIR_DNG] = dngDirMap

android/app/src/main/kotlin/deckers/thibault/aves/metadata/Metadata.kt

@@ -120,7 +120,7 @@ object Metadata {
         return date.time + parseSubSecond(subSecond)
     }
 
-    // Opening large PSD/TIFF files yields an OOM (both with `metadata-extractor` v2.15.0 and `ExifInterface` v1.3.1),
+    // Opening some large files yields an OOM (both with `metadata-extractor` v2.15.0 and `ExifInterface` v1.3.1),
     // so we define an arbitrary threshold to avoid a crash on launch.
     // It is not clear whether it is because of the file itself or its metadata.
     private const val FILE_SIZE_MAX = 100 * (1 shl 20) // MB
@@ -136,6 +136,8 @@ object Metadata {
     private fun getSafeUri(context: Context, uri: Uri, mimeType: String, sizeBytes: Long?): Uri {
         return when (mimeType) {
             // formats known to yield OOM for large files
+            MimeTypes.DNG,
+            MimeTypes.DNG_ADOBE,
             MimeTypes.HEIC,
             MimeTypes.HEIF,
             MimeTypes.MP4,

android/app/src/main/kotlin/deckers/thibault/aves/metadata/metadataextractor/Helper.kt

@@ -60,19 +60,20 @@ object Helper {
     // e.g. "exif [...] 134 [...] 4578696600004949[...]"
     private val PNG_RAW_PROFILE_PATTERN = Regex("^\\n(.*?)\\n\\s*(\\d+)\\n(.*)", RegexOption.DOT_MATCHES_ALL)
 
-    // providing the stream length is risky, as it may crash if it is incorrect
-    private const val SAFE_READ_STREAM_LENGTH = -1L
-
     fun readMimeType(input: InputStream): String? {
         val bufferedInputStream = if (input is BufferedInputStream) input else BufferedInputStream(input)
         return FileTypeDetector.detectFileType(bufferedInputStream).mimeType
     }
 
     @Throws(IOException::class, ImageProcessingException::class)
-    fun safeRead(input: InputStream, sizeBytes: Long?): com.drew.metadata.Metadata {
+    fun safeRead(input: InputStream, @Suppress("unused_parameter") sizeBytes: Long?): com.drew.metadata.Metadata {
         val inputStream = if (input is BufferedInputStream) input else BufferedInputStream(input)
         val fileType = FileTypeDetector.detectFileType(inputStream)
-        val streamLength = sizeBytes ?: SAFE_READ_STREAM_LENGTH
+
+        // Providing the stream length is risky, as it may crash if it is incorrect.
+        // Not providing the stream length is also risky, as it may lead to OOM
+        // when `RandomAccessStreamReader` reads the entire stream to validate offsets.
+        val undefinedStreamLength = -1L
 
         val metadata = when (fileType) {
             FileType.Jpeg -> safeReadJpeg(inputStream)
@@ -84,9 +85,9 @@ object Helper {
             FileType.Cr2,
             FileType.Nef,
             FileType.Orf,
-            FileType.Rw2 -> safeReadTiff(inputStream, streamLength)
+            FileType.Rw2 -> safeReadTiff(inputStream, undefinedStreamLength)
 
-            else -> ImageMetadataReader.readMetadata(inputStream, streamLength, fileType)
+            else -> ImageMetadataReader.readMetadata(inputStream, undefinedStreamLength, fileType)
         }
 
         metadata.addDirectory(FileTypeDirectory(fileType))

android/app/src/main/kotlin/deckers/thibault/aves/utils/MimeTypes.kt

@@ -28,7 +28,8 @@ object MimeTypes {
     private const val CR2 = "image/x-canon-cr2"
     private const val CRW = "image/x-canon-crw"
     private const val DCR = "image/x-kodak-dcr"
-    const val DNG = "image/x-adobe-dng"
+    const val DNG = "image/dng"
+    const val DNG_ADOBE = "image/x-adobe-dng"
     private const val ERF = "image/x-epson-erf"
     private const val K25 = "image/x-kodak-k25"
     private const val KDC = "image/x-kodak-kdc"
@@ -71,7 +72,7 @@ object MimeTypes {
 
     fun isRaw(mimeType: String): Boolean {
         return when (mimeType) {
-            ARW, CR2, CRW, DCR, DNG, ERF, K25, KDC, MRW, NEF, NRW, ORF, PEF, RAF, RAW, RW2, SR2, SRF, SRW, X3F -> true
+            ARW, CR2, CRW, DCR, DNG, DNG_ADOBE, ERF, K25, KDC, MRW, NEF, NRW, ORF, PEF, RAF, RAW, RW2, SR2, SRF, SRW, X3F -> true
             else -> false
         }
     }
@@ -142,7 +143,7 @@ object MimeTypes {
         return if (pageId != null && MultiPageImage.isSupported(mimeType)) {
             true
         } else when (mimeType) {
-            DNG, HEIC, HEIF, PNG, WEBP -> true
+            DNG, DNG_ADOBE, HEIC, HEIF, PNG, WEBP -> true
             else -> false
         }
     }
@@ -151,7 +152,7 @@ object MimeTypes {
     // according to EXIF orientation when decoding images of known formats
     // but we need to rotate the decoded bitmap for the other formats
     fun needRotationAfterContentResolverThumbnail(mimeType: String) = when (mimeType) {
-        DNG, PNG -> true
+        DNG, DNG_ADOBE, PNG -> true
         else -> false
     }