1 files changed, 129 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/IOUtils.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/IOUtils.java
new file mode 100644
index 000000000..62eee5192
--- /dev/null
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/IOUtils.java
@@ -0,0 +1,129 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.util;
+
+import android.util.Log;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Static helper class containing useful methods for manipulating IO objects.
+ */
+public class IOUtils {
+    private static final String LOGTAG = "GeckoIOUtils";
+
+    /**
+     * Represents the result of consuming an input stream, holding the returned data as well
+     * as the length of the data returned.
+     * The byte[] is not guaranteed to be trimmed to the size of the data acquired from the stream:
+     * hence the need for the length field. This strategy avoids the need to copy the data into a
+     * trimmed buffer after consumption.
+     */
+    public static class ConsumedInputStream {
+        public final int consumedLength;
+        // Only reassigned in getTruncatedData.
+        private byte[] consumedData;
+
+        public ConsumedInputStream(int consumedLength, byte[] consumedData) {
+            this.consumedLength = consumedLength;
+            this.consumedData = consumedData;
+        }
+
+        /**
+         * Get the data trimmed to the length of the actual payload read, caching the result.
+         */
+        public byte[] getTruncatedData() {
+            if (consumedData.length == consumedLength) {
+                return consumedData;
+            }
+
+            consumedData = truncateBytes(consumedData, consumedLength);
+            return consumedData;
+        }
+
+        public byte[] getData() {
+            return consumedData;
+        }
+    }
+
+    /**
+     * Fully read an InputStream into a byte array.
+     * @param iStream the InputStream to consume.
+     * @param bufferSize The initial size of the buffer to allocate. It will be grown as
+     *                   needed, but if the caller knows something about the InputStream then
+     *                   passing a good value here can improve performance.
+     */
+    public static ConsumedInputStream readFully(InputStream iStream, int bufferSize) {
+        // Allocate a buffer to hold the raw data downloaded.
+        byte[] buffer = new byte[bufferSize];
+
+        // The offset of the start of the buffer's free space.
+        int bPointer = 0;
+
+        // The quantity of bytes the last call to read yielded.
+        int lastRead = 0;
+        try {
+            // Fully read the data into the buffer.
+            while (lastRead != -1) {
+                // Read as many bytes as are currently available into the buffer.
+                lastRead = iStream.read(buffer, bPointer, buffer.length - bPointer);
+                bPointer += lastRead;
+
+                // If buffer has overflowed, double its size and carry on.
+                if (bPointer == buffer.length) {
+                    bufferSize *= 2;
+                    byte[] newBuffer = new byte[bufferSize];
+
+                    // Copy the contents of the old buffer into the new buffer.
+                    System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
+                    buffer = newBuffer;
+                }
+            }
+
+            return new ConsumedInputStream(bPointer + 1, buffer);
+        } catch (IOException e) {
+            Log.e(LOGTAG, "Error consuming input stream.", e);
+        } finally {
+            try {
+                iStream.close();
+            } catch (IOException e) {
+                Log.e(LOGTAG, "Error closing input stream.", e);
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Truncate a given byte[] to a given length. Returns a new byte[] with the first length many
+     * bytes of the input.
+     */
+    public static byte[] truncateBytes(byte[] bytes, int length) {
+        byte[] newBytes = new byte[length];
+        System.arraycopy(bytes, 0, newBytes, 0, length);
+
+        return newBytes;
+    }
+
+    public static void safeStreamClose(Closeable stream) {
+        try {
+            if (stream != null)
+                stream.close();
+        } catch (IOException e) { }
+    }
+
+    public static void copy(InputStream in, OutputStream out) throws IOException {
+        byte[] buffer = new byte[4096];
+        int len;
+
+        while ((len = in.read(buffer)) != -1) {
+            out.write(buffer, 0, len);
+        }
+    }
+}