1 files changed, 83 insertions, 0 deletions
diff --git a/java/org/brotli/wrapper/android/JniHelper.java b/java/org/brotli/wrapper/android/JniHelper.java
new file mode 100644
index 0000000..4ec9fe5
--- /dev/null
+++ b/java/org/brotli/wrapper/android/JniHelper.java
@@ -0,0 +1,83 @@
+package org.brotli.wrapper.android;
+
+import android.content.Context;
+import android.os.Build;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.zip.ZipFile;
+
+public class JniHelper {
+
+  // Should be set on application start.
+  static Context context = null;
+
+  private static final String LIB_NAME = "native";
+
+  private static void tryInitialize() {
+    try {
+      System.loadLibrary(LIB_NAME);
+    } catch (UnsatisfiedLinkError e) {
+      if (context == null) {
+        throw e;
+      }
+      int sdk = Build.VERSION.SDK_INT;
+      boolean tryFallback =
+          (sdk >= Build.VERSION_CODES.JELLY_BEAN) && (sdk <= Build.VERSION_CODES.KITKAT);
+      if (!tryFallback) {
+        throw e;
+      }
+      try {
+        String libraryFileName = "lib" + LIB_NAME + ".so";
+        String libraryFullPath = context.getFilesDir() + File.separator + libraryFileName;
+        File file = new File(libraryFullPath);
+        if (!file.exists()) {
+          String apkPath = context.getApplicationInfo().sourceDir;
+          String pathInApk = "lib/" + Build.CPU_ABI + "/lib" + LIB_NAME + ".so";
+          unzip(apkPath, pathInApk, libraryFullPath);
+        }
+        System.load(libraryFullPath);
+      } catch (UnsatisfiedLinkError unsatisfiedLinkError) {
+        throw unsatisfiedLinkError;
+      } catch (Throwable t) {
+        UnsatisfiedLinkError unsatisfiedLinkError = new UnsatisfiedLinkError(
+            "Exception while extracting native library: " + t.getMessage());
+        unsatisfiedLinkError.initCause(t);
+        throw unsatisfiedLinkError;
+      }
+    }
+  }
+
+  private static final Object mutex = new Object();
+  private static volatile boolean alreadyInitialized;
+
+  public static void ensureInitialized() {
+    synchronized (mutex) {
+      if (!alreadyInitialized) {
+        // If failed, do not retry.
+        alreadyInitialized = true;
+        tryInitialize();
+      }
+    }
+  }
+
+  private static void unzip(String zipFileName, String entryName, String outputFileName)
+      throws IOException {
+    ZipFile zipFile = new ZipFile(zipFileName);
+    try {
+      InputStream input = zipFile.getInputStream(zipFile.getEntry(entryName));
+      OutputStream output = new FileOutputStream(outputFileName);
+      byte[] data = new byte[16384];
+      int len;
+      while ((len = input.read(data)) != -1) {
+        output.write(data, 0, len);
+      }
+      output.close();
+      input.close();
+    } finally {
+      zipFile.close();
+    }
+  }
+}