Try to cache streaming contents

app/src/main/java/com/cappielloantonio/tempo/util/StreamingCacheDataSource.kt

@@ -0,0 +1,61 @@
+package com.cappielloantonio.tempo.util
+
+import android.net.Uri
+import android.util.Log
+import androidx.media3.common.C
+import androidx.media3.common.util.UnstableApi
+import androidx.media3.datasource.DataSource
+import androidx.media3.datasource.DataSpec
+import androidx.media3.datasource.TransferListener
+import androidx.media3.datasource.cache.CacheDataSource
+import androidx.media3.datasource.cache.ContentMetadata
+
+@UnstableApi
+class StreamingCacheDataSource private constructor(
+    private val cacheDataSource: CacheDataSource,
+): DataSource {
+    private val TAG = "StreamingCacheDataSource"
+
+    private var currentDataSpec: DataSpec? = null
+
+    class Factory(private val cacheDatasourceFactory: CacheDataSource.Factory): DataSource.Factory {
+        override fun createDataSource(): DataSource {
+            return StreamingCacheDataSource(cacheDatasourceFactory.createDataSource())
+        }
+    }
+
+    override fun read(buffer: ByteArray, offset: Int, length: Int): Int {
+        return cacheDataSource.read(buffer, offset, length)
+    }
+
+    override fun addTransferListener(transferListener: TransferListener) {
+        return cacheDataSource.addTransferListener(transferListener)
+    }
+
+    override fun open(dataSpec: DataSpec): Long {
+        val ret = cacheDataSource.open(dataSpec)
+        currentDataSpec = dataSpec
+        Log.d(TAG, "Opened $currentDataSpec")
+        return ret
+    }
+
+    override fun getUri(): Uri? {
+        return cacheDataSource.uri
+    }
+
+    override fun close() {
+        cacheDataSource.close()
+        Log.d(TAG, "Closed $currentDataSpec")
+        val dataSpec = currentDataSpec
+        if (dataSpec != null) {
+            val cacheKey = cacheDataSource.cacheKeyFactory.buildCacheKey(dataSpec)
+            val contentLength = ContentMetadata.getContentLength(cacheDataSource.cache.getContentMetadata(cacheKey));
+            if (contentLength == C.LENGTH_UNSET.toLong()) {
+                Log.d(TAG, "Removing partial cache for $cacheKey")
+                cacheDataSource.cache.removeResource(cacheKey)
+            } else {
+                Log.d(TAG, "Key $cacheKey has been fully cached")
+            }
+        }
+    }
+}