1 files changed, 120 insertions, 0 deletions
diff --git a/androidApp/src/main/java/mx/trackermap/TrackerMap/android/shared/FileCache.kt b/androidApp/src/main/java/mx/trackermap/TrackerMap/android/shared/FileCache.kt
new file mode 100644
index 0000000..16777de
--- /dev/null
+++ b/androidApp/src/main/java/mx/trackermap/TrackerMap/android/shared/FileCache.kt
@@ -0,0 +1,120 @@
+package mx.trackermap.TrackerMap.android.shared
+
+import android.content.Context
+import android.net.Uri
+import android.provider.OpenableColumns
+import android.webkit.MimeTypeMap
+import java.io.BufferedInputStream
+import java.io.BufferedOutputStream
+import java.io.File
+import java.io.FileOutputStream
+
+// Source: https://techenum.com/android-content-uri-how-to-get-the-file-uri/
+class FileCache(
+    private val context: Context
+) {
+
+    // content resolver
+    private val contentResolver = context.contentResolver
+
+    // to get the type of file
+    private val mimeTypeMap = MimeTypeMap.getSingleton()
+
+    private val mCacheLocation = File(context.cacheDir, "reports_tmp")
+
+    fun cacheThis(uris: List<Uri>) {
+        uris.forEach { uri -> copyFromSource(uri) }
+    }
+
+    /**
+     * Copies the actual data from provided content provider.
+     */
+    private fun copyFromSource(uri: Uri) {
+
+        val fileExtension: String = getFileExtension(uri) ?: kotlin.run {
+            throw RuntimeException("Extension is null for $uri")
+        }
+        val fileName = queryName(uri) ?: getFileName(fileExtension)
+
+        val inputStream = contentResolver.openInputStream(uri) ?: kotlin.run {
+            throw RuntimeException("Cannot open for reading $uri")
+        }
+        val bufferedInputStream = BufferedInputStream(inputStream)
+
+        // the file which will be the new cached file
+        val outputFile = File(mCacheLocation, fileName)
+        if (!outputFile.exists()) {
+            outputFile.parentFile?.mkdirs()
+        } else {
+            outputFile.delete()
+        }
+        val bufferedOutputStream = BufferedOutputStream(FileOutputStream(outputFile))
+
+        // this will hold the content for each iteration
+        val buffer = ByteArray(DEFAULT_BUFFER_SIZE)
+
+        var readBytes: Int // will be -1 if reached the end of file
+
+        while (true) {
+            readBytes = bufferedInputStream.read(buffer)
+
+            // check if the read was failure
+            if (readBytes == -1) {
+                bufferedOutputStream.flush()
+                break
+            }
+
+            bufferedOutputStream.write(buffer)
+            bufferedOutputStream.flush()
+        }
+
+        // close everything
+        inputStream.close()
+        bufferedInputStream.close()
+        bufferedOutputStream.close()
+
+    }
+
+    private fun getFileExtension(uri: Uri): String? {
+        return mimeTypeMap.getExtensionFromMimeType(contentResolver.getType(uri))
+    }
+
+    /**
+     * Tries to get actual name of the file being copied.
+     * This might be required in some of the cases where you might want to know the file name too.
+     *
+     * @param uri
+     *
+     */
+    private fun queryName(uri: Uri): String? {
+        val returnCursor = contentResolver.query(uri, null, null, null, null) ?: return null
+        val nameIndex: Int = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+        returnCursor.moveToFirst()
+        val name: String = returnCursor.getString(nameIndex)
+        returnCursor.close()
+        return name
+    }
+
+    private fun getFileName(fileExtension: String): String {
+        return "${System.currentTimeMillis()}.$fileExtension"
+    }
+
+    /**
+     * Remove everything that we have cached.
+     * You might want to invoke this method before quiting the application.
+     */
+    fun removeAll() {
+        mCacheLocation.deleteRecursively()
+    }
+
+    companion object {
+
+        // base buffer size
+        private const val BASE_BUFFER_SIZE = 1024
+
+        // if you want to modify size use binary multiplier 2, 4, 6, 8
+        private const val DEFAULT_BUFFER_SIZE = BASE_BUFFER_SIZE * 4
+
+    }
+
+}
+\ No newline at end of file