Add DocumentProvider for accessing internal files

On Android 12 and above, files from an application's external storage directory cannot be accessed by the user. The only proper SAF-compliant way to solve this is to create a `DocumentProvider` which proxies access to internal storage accordingly.
This commit is contained in:
Mylah Dee 2022-05-28 18:29:01 -05:00 committed by ◱ Mark
parent 7aa6a5c4ca
commit ee7da31fc6
3 changed files with 287 additions and 1 deletions

View File

@ -106,7 +106,7 @@
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="skyline.emu.fileprovider"
android:authorities="emu.skyline.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
@ -114,6 +114,17 @@
android:resource="@xml/filepaths" />
</provider>
<provider
android:name="emu.skyline.provider.DocumentsProvider"
android:authorities="emu.skyline.provider.documents"
android:grantUriPermissions="true"
android:exported="true"
android:permission="android.permission.MANAGE_DOCUMENTS">
<intent-filter>
<action android:name="android.content.action.DOCUMENTS_PROVIDER" />
</intent-filter>
</provider>
<meta-data
android:name="com.android.graphics.injectLayers.enable"
android:value="true" />

View File

@ -20,8 +20,18 @@ fun Context.getPublicFilesDir() : File = getExternalFilesDir(null) ?: filesDir
class SkylineApplication : Application() {
private external fun initializeLog(appFilesPath : String, logLevel : Int)
init {
instance = this
}
companion object {
lateinit var instance : SkylineApplication
private set
}
override fun onCreate() {
super.onCreate()
instance = this
System.loadLibrary("skyline")
val appFilesPath = applicationContext.getPublicFilesDir().canonicalPath

View File

@ -0,0 +1,265 @@
/*
* SPDX-License-Identifier: MPL-2.0
* Copyright © 2022 Skyline Team and Contributors (https://github.com/skyline-emu/)
*/
package emu.skyline.provider
import android.database.Cursor
import android.database.MatrixCursor
import android.os.CancellationSignal
import android.os.ParcelFileDescriptor
import android.provider.DocumentsContract
import android.provider.DocumentsProvider
import android.webkit.MimeTypeMap
import emu.skyline.R
import emu.skyline.SkylineApplication
import emu.skyline.getPublicFilesDir
import java.io.*
class DocumentsProvider : DocumentsProvider() {
private val baseDirectory = File(SkylineApplication.instance.getPublicFilesDir().canonicalPath)
companion object {
private val DEFAULT_ROOT_PROJECTION : Array<String> = arrayOf(
DocumentsContract.Root.COLUMN_ROOT_ID,
DocumentsContract.Root.COLUMN_MIME_TYPES,
DocumentsContract.Root.COLUMN_FLAGS,
DocumentsContract.Root.COLUMN_ICON,
DocumentsContract.Root.COLUMN_TITLE,
DocumentsContract.Root.COLUMN_SUMMARY,
DocumentsContract.Root.COLUMN_DOCUMENT_ID,
DocumentsContract.Root.COLUMN_AVAILABLE_BYTES
)
private val DEFAULT_DOCUMENT_PROJECTION : Array<String> = arrayOf(
DocumentsContract.Document.COLUMN_DOCUMENT_ID,
DocumentsContract.Document.COLUMN_MIME_TYPE,
DocumentsContract.Document.COLUMN_DISPLAY_NAME,
DocumentsContract.Document.COLUMN_LAST_MODIFIED,
DocumentsContract.Document.COLUMN_FLAGS,
DocumentsContract.Document.COLUMN_SIZE
)
}
override fun onCreate() : Boolean {
return true
}
/**
* @return The [File] that corresponds to the document ID supplied by [getDocumentId]
*/
private fun getFile(documentId : String) : File {
val file = File(documentId)
if (!file.exists()) throw FileNotFoundException(file.absolutePath + " not found")
return file
}
/**
* @return A unique ID for the provided [File]
*/
private fun getDocumentId(file : File) : Any? {
return file.absolutePath
}
override fun queryRoots(projection : Array<out String>?) : Cursor {
val cursor = MatrixCursor(projection ?: DEFAULT_ROOT_PROJECTION)
val applicationTitle = SkylineApplication.instance.applicationInfo.loadLabel(SkylineApplication.instance.packageManager).toString()
val baseDirectoryDocumentId = getDocumentId(baseDirectory)
cursor.newRow().apply {
add(DocumentsContract.Root.COLUMN_ROOT_ID, baseDirectoryDocumentId)
add(DocumentsContract.Root.COLUMN_SUMMARY, null)
add(DocumentsContract.Root.COLUMN_FLAGS, DocumentsContract.Root.FLAG_SUPPORTS_CREATE or DocumentsContract.Root.FLAG_SUPPORTS_IS_CHILD)
add(DocumentsContract.Root.COLUMN_TITLE, applicationTitle)
add(DocumentsContract.Root.COLUMN_DOCUMENT_ID, baseDirectoryDocumentId)
add(DocumentsContract.Root.COLUMN_MIME_TYPES, "*/*")
add(DocumentsContract.Root.COLUMN_AVAILABLE_BYTES, baseDirectory.freeSpace)
add(DocumentsContract.Root.COLUMN_ICON, R.drawable.logo_skyline)
}
return cursor
}
override fun queryDocument(documentId : String?, projection : Array<out String>?) : Cursor {
val cursor = MatrixCursor(projection ?: DEFAULT_DOCUMENT_PROJECTION)
return includeFile(cursor, documentId, null)
}
override fun isChildDocument(parentDocumentId : String?, documentId : String?) : Boolean {
return documentId?.startsWith(parentDocumentId!!) ?: false
}
override fun createDocument(parentDocumentId : String?, mimeType : String?, displayName : String) : String? {
var newFile = File(parentDocumentId, displayName)
var noConflictId = 1 // Makes sure two files don't have the same name by adding a number to the end
while (newFile.exists())
newFile = File(parentDocumentId, "$displayName (${noConflictId++})")
try {
if (DocumentsContract.Document.MIME_TYPE_DIR == mimeType) {
if (!newFile.mkdir())
throw IOException("Failed to create directory")
} else {
if (!newFile.createNewFile())
throw IOException("Failed to create file")
}
} catch (e : IOException) {
throw FileNotFoundException("Couldn't create document '${newFile.path}': ${e.message}")
}
return newFile.path
}
override fun deleteDocument(documentId : String?) {
val file = getFile(documentId!!)
if (!file.delete())
throw FileNotFoundException("Couldn't delete document with ID '$documentId'")
}
override fun removeDocument(documentId : String, parentDocumentId : String?) {
val parent = getFile(parentDocumentId!!)
val file = getFile(documentId)
var doesFileParentMatch = false
val fileParent = file.parentFile
if (fileParent == null || fileParent.equals(parent))
doesFileParentMatch = true
if (parent == file || doesFileParentMatch) {
if (!file.delete())
throw FileNotFoundException("Couldn't delete document with ID '$documentId'")
} else {
throw FileNotFoundException("Couldn't delete document with ID '$documentId'")
}
}
override fun renameDocument(documentId : String?, displayName : String?) : String? {
if (displayName == null)
throw FileNotFoundException("Couldn't rename document '$documentId' as the new name is null")
val sourceFile = getFile(documentId!!)
val sourceParentFile = sourceFile.parentFile ?: throw FileNotFoundException("Couldn't rename document '$documentId' as it has no parent")
val destFile = File(sourceParentFile.path, displayName)
try {
if (!sourceFile.renameTo(destFile))
throw FileNotFoundException("Couldn't rename document from '${sourceFile.name}' to '${destFile.name}'")
} catch (e : Exception) {
throw FileNotFoundException("Couldn't rename document from '${sourceFile.name}' to '${destFile.name}': ${e.message}")
}
return getDocumentId(destFile).toString()
}
private fun copyDocument(
sourceDocumentId : String, sourceParentDocumentId : String,
targetParentDocumentId : String?
) : String? {
if (!isChildDocument(sourceParentDocumentId, sourceDocumentId))
throw FileNotFoundException("Couldn't copy document '$sourceDocumentId' as its parent is not '$sourceParentDocumentId'")
return copyDocument(sourceDocumentId, targetParentDocumentId)
}
override fun copyDocument(sourceDocumentId : String, targetParentDocumentId : String?) : String? {
val parent = getFile(targetParentDocumentId!!)
val oldFile = getFile(sourceDocumentId)
val newFile = File(parent.path, oldFile.name)
try {
if (!(newFile.createNewFile() && newFile.setWritable(true) && newFile.setReadable(true)))
throw IOException("Couldn't create new file")
FileInputStream(oldFile).use { inStream ->
FileOutputStream(newFile).use { outStream ->
inStream.copyTo(outStream)
}
}
} catch (e : IOException) {
throw FileNotFoundException("Couldn't copy document '$sourceDocumentId': ${e.message}")
}
return getDocumentId(newFile).toString()
}
override fun moveDocument(
sourceDocumentId : String, sourceParentDocumentId : String?,
targetParentDocumentId : String?
) : String? {
try {
val newDocumentId = copyDocument(
sourceDocumentId, sourceParentDocumentId!!,
targetParentDocumentId
)
removeDocument(sourceDocumentId, sourceParentDocumentId)
return newDocumentId
} catch (e : FileNotFoundException) {
throw FileNotFoundException("Couldn't move document '$sourceDocumentId'")
}
}
private fun includeFile(cursor : MatrixCursor, documentId : String?, file : File?) : MatrixCursor {
val localDocumentId = documentId ?: file?.let { getDocumentId(it) } as String?
val localFile = file ?: getFile(documentId.toString())
var flags = 0
if (localFile.isDirectory && localFile.canWrite()) {
flags = DocumentsContract.Document.FLAG_DIR_SUPPORTS_CREATE
} else if (localFile.canWrite()) {
flags = DocumentsContract.Document.FLAG_SUPPORTS_WRITE
flags = flags or DocumentsContract.Document.FLAG_SUPPORTS_DELETE
flags = flags or DocumentsContract.Document.FLAG_SUPPORTS_REMOVE
flags = flags or DocumentsContract.Document.FLAG_SUPPORTS_MOVE
flags = flags or DocumentsContract.Document.FLAG_SUPPORTS_COPY
flags = flags or DocumentsContract.Document.FLAG_SUPPORTS_RENAME
}
val displayName = localFile.name
val mimeType = getTypeForFile(localFile)
cursor.newRow().apply {
add(DocumentsContract.Document.COLUMN_DOCUMENT_ID, localDocumentId)
add(DocumentsContract.Document.COLUMN_DISPLAY_NAME, displayName)
add(DocumentsContract.Document.COLUMN_SIZE, localFile.length())
add(DocumentsContract.Document.COLUMN_MIME_TYPE, mimeType)
add(DocumentsContract.Document.COLUMN_LAST_MODIFIED, localFile.lastModified())
add(DocumentsContract.Document.COLUMN_FLAGS, flags)
}
return cursor
}
private fun getTypeForFile(file : File) : Any? {
return if (file.isDirectory)
DocumentsContract.Document.MIME_TYPE_DIR
else
getTypeForName(file.name)
}
private fun getTypeForName(name : String) : Any? {
val lastDot = name.lastIndexOf('.')
if (lastDot >= 0) {
val extension = name.substring(lastDot + 1)
val mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension)
if (mime != null)
return mime
}
return "application/octect-stream"
}
override fun queryChildDocuments(parentDocumentId : String?, projection : Array<out String>?, sortOrder : String?) : Cursor {
var cursor = MatrixCursor(projection ?: DEFAULT_DOCUMENT_PROJECTION)
val parent = getFile(parentDocumentId!!)
for (file in parent.listFiles()!!)
cursor = includeFile(cursor, null, file)
return cursor
}
override fun openDocument(documentId : String?, mode : String?, signal : CancellationSignal?) : ParcelFileDescriptor {
val file = documentId?.let { getFile(it) }
val accessMode = ParcelFileDescriptor.parseMode(mode)
return ParcelFileDescriptor.open(file, accessMode)
}
}