Check file size is valid and catch OOM error

Author: martinwork

app/src/main/java/com/samsung/microbit/utils/FileUtils.java

@@ -196,18 +196,50 @@ public static long fileSizeFromUri( Uri uri, Context ctx) {
         return -1;
     }
 
-    public static byte[] readBytesFromInputStream(InputStream is, final int size) {
+    public static String runtimeMemory() {
+        Runtime runtime = Runtime.getRuntime();
+        long totalMemory = runtime.totalMemory();
+        long maxMemory = runtime.maxMemory();
+        long freeMemory = runtime.freeMemory();
+        return "memory: total" + totalMemory + "; max " + maxMemory + "; free " + freeMemory;
+    }
+
+    public static byte[] newBytes(final int size) {
+        Log.d( TAG, "newBytes(" + size + ") " + runtimeMemory());
+        if ( size <= 0) {
+            return null;
+        }
+
         byte[] bytes = null;
         try {
             bytes = new byte[size];
+        }  catch ( Exception e) {
+            bytes = null;
+        }  catch ( OutOfMemoryError oom) {
+            bytes = null;
+        }
+        return bytes;
+    }
+
+    public static byte[] readBytesFromInputStream(InputStream is, final int size) {
+        if ( size <= 0) {
+            return null;
+        }
+
+        byte[] bytes = null;
+        try {
+            bytes = newBytes(size);
+            if ( bytes == null) {
+                return null;
+            }
             int remain = size;
             int offset = 0;
             while ( remain > 0) {
                 int read = is.read( bytes, offset, remain);
                 remain -= read;
                 offset += read;
             }
-        }  catch ( Exception e){
+        }  catch ( Exception e) {
             bytes = null;
         }
         return bytes;
@@ -216,8 +248,11 @@ public static byte[] readBytesFromInputStream(InputStream is, final int size) {
     public static byte[] readBytesFromFile( File file) {
         byte[] bytes = null;
         try {
-            FileInputStream is = new FileInputStream( file);
             int size = (int) file.length();
+            if ( size <= 0) {
+                return null;
+            }
+            FileInputStream is = new FileInputStream( file);
             bytes = readBytesFromInputStream(is, size);
             is.close();
         }  catch ( Exception e){
@@ -229,9 +264,12 @@ public static byte[] readBytesFromFile( File file) {
     public static byte[] readBytesFromUri( Uri uri, Context ctx) {
         byte[] bytes = null;
         try {
+            int size = (int) fileSizeFromUri( uri, ctx);
+            if ( size <= 0) {
+                return null;
+            }
             InputStream is = ctx.getContentResolver().openInputStream( uri);
             if ( is != null) {
-                int size = (int) fileSizeFromUri( uri, ctx);
                 bytes = readBytesFromInputStream( is, size);
                 is.close();
             }
@@ -241,7 +279,6 @@ public static byte[] readBytesFromUri( Uri uri, Context ctx) {
         return bytes;
     }
 
-
     public static boolean stringBuilderAddStream( StringBuilder sb, InputStream is) {
         boolean ok = true;
         try {