src/main/java/io/lbry/browser/ServiceHelper.java

@@ -2,8 +2,22 @@ package io.lbry.browser;
 
 import android.content.Intent;
 import android.content.Context;
+import android.content.res.AssetFileDescriptor;
+import android.content.SharedPreferences;
+import android.os.AsyncTask;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.InputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
 
 public class ServiceHelper {
+
+    private static final String TAG = "io.lbry.browser.ServiceHelper";
+
+    private static final String HEADERS_ASSET_KEY = "headersAssetInitialized";
+
     public static Intent buildIntent(Context ctx, String pythonServiceArgument, Class serviceClass, String pythonName) {
         Intent intent = new Intent(ctx, serviceClass);
         String argument = ctx.getFilesDir().getAbsolutePath() + "/app";
@@ -18,13 +32,83 @@ public class ServiceHelper {
         return intent;
     }
 
-    public static void start(Context ctx, String pythonServiceArgument, Class serviceClass, String pythonName) {
-        Intent intent = buildIntent(ctx, pythonServiceArgument, serviceClass, pythonName);
-        ctx.startService(intent);
+    public static void start(final Context ctx, String pythonServiceArgument, Class serviceClass, String pythonName) {
+        // always check initial headers status before starting the service
+        final SharedPreferences sp = ctx.getSharedPreferences(MainActivity.SHARED_PREFERENCES_NAME, Context.MODE_PRIVATE);
+        boolean initHeaders = sp.getBoolean(HEADERS_ASSET_KEY, false);
+        if (initHeaders) {
+            // initial headers asset copy already done. simply start the service
+            Intent intent = buildIntent(ctx, pythonServiceArgument, serviceClass, pythonName);
+            ctx.startService(intent);
+            return;
+        }
+
+        (new AsyncTask<Void, Void, Void>() {
+            @Override
+            protected Void doInBackground(Void... params) {
+                String targetPath = String.format("%s/lbryum/lbc_mainnet", Utils.getAppInternalStorageDir(ctx));
+                File targetDir = new File(targetPath);
+                if (!targetDir.exists()) {
+                    targetDir.mkdirs();
+                }
+
+                String headersPath = String.format("%s/headers", targetPath);
+                android.util.Log.d(TAG, String.format("HeadersPath: %s", headersPath));
+                File targetHeadersFile = new File(headersPath);
+                InputStream in = null;
+                FileOutputStream out = null;
+
+                long sourceLen = 0;
+                long targetLen = 0;
+                try {
+                    android.util.Log.d(TAG, "Opening asset: blockchain/headers");
+                    in = ctx.getAssets().open("blockchain/headers");
+                    out = new FileOutputStream(targetHeadersFile);
+                    byte[] b = new byte[1120]; // 10 headers at a time?
+                    int len;
+                    while ((len = in.read(b, 0, 1120)) > 0) {
+                        sourceLen += len;
+                        out.write(b, 0, len);
+                    }
+                } catch (Exception ex) {
+                    // failed to copy the headers. sdk will perform the download instead.
+                    android.util.Log.e(TAG, "failed to copy headers asset", ex);
+                } finally {
+                    closeStream(in);
+                    closeStream(out);
+
+                    // only mark the copy as successful if the file sizes are the same
+                    targetLen = targetHeadersFile.exists() ? targetHeadersFile.length() : 0;
+                    android.util.Log.d(TAG, String.format("SourceLength=%d; TargetLength=%d", sourceLen, targetLen));
+                    if (targetLen > 0 && targetLen == sourceLen) {
+                        SharedPreferences.Editor editor = sp.edit();
+                        editor.putBoolean(HEADERS_ASSET_KEY, true);
+                        editor.commit();
+                    }
+                }
+
+                return null;
+            }
+
+            protected void onPostExecute(Void result) {
+                Intent intent = buildIntent(ctx, pythonServiceArgument, serviceClass, pythonName);
+                ctx.startService(intent);
+            }
+        }).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
     }
 
     public static void stop(Context ctx, Class serviceClass) {
         Intent intent = new Intent(ctx, serviceClass);
         ctx.stopService(intent);
     }
+
+    private static void closeStream(Closeable closeable) {
+        try {
+            if (closeable != null) {
+                closeable.close();
+            }
+        } catch (IOException ex) {
+            // pass
+        }
+    }
 }

src/main/java/io/lbry/browser/reactmodules/UtilityModule.java

@@ -30,6 +30,9 @@ import com.facebook.react.common.MapBuilder;
 import com.squareup.picasso.Picasso;
 
 import java.io.File;
+import java.io.Closeable;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;