Extract delta client

Summary: Extracts the delta client from the bundle downloader. This will allow us to extract an interface, and provide a different implementation for C++ delta bundling (where we will pass deltas directly to native code).

Reviewed By: pakoito

Differential Revision: D6900904

fbshipit-source-id: 358705615eecc15afa0de3e50478468ad840d250

Author: davidaurelio

ReactAndroid/src/main/java/com/facebook/react/devsupport/BundleDeltaClient.java

@@ -0,0 +1,121 @@
+package com.facebook.react.devsupport;
+
+import android.util.JsonReader;
+import android.util.JsonToken;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.LinkedHashMap;
+import javax.annotation.Nullable;
+import okio.BufferedSource;
+
+public class BundleDeltaClient {
+
+  final LinkedHashMap<Number, byte[]> mPreModules = new LinkedHashMap<Number, byte[]>();
+  final LinkedHashMap<Number, byte[]> mDeltaModules = new LinkedHashMap<Number, byte[]>();
+  final LinkedHashMap<Number, byte[]> mPostModules = new LinkedHashMap<Number, byte[]>();
+  @Nullable String mDeltaId;
+
+  static boolean isDeltaUrl(String bundleUrl) {
+    return bundleUrl.indexOf(".delta?") != -1;
+  }
+
+  public void reset() {
+    mDeltaId = null;
+    mDeltaModules.clear();
+    mPreModules.clear();
+    mPostModules.clear();
+  }
+
+  public String toDeltaUrl(String bundleURL) {
+    if (isDeltaUrl(bundleURL) && mDeltaId != null) {
+      return bundleURL + "&deltaBundleId=" + mDeltaId;
+    }
+    return bundleURL;
+  }
+
+  public synchronized boolean storeDeltaInFile(BufferedSource body, File outputFile)
+    throws IOException {
+
+    JsonReader jsonReader = new JsonReader(new InputStreamReader(body.inputStream()));
+
+    jsonReader.beginObject();
+
+    int numChangedModules = 0;
+
+    while (jsonReader.hasNext()) {
+      String name = jsonReader.nextName();
+      if (name.equals("id")) {
+        mDeltaId = jsonReader.nextString();
+      } else if (name.equals("pre")) {
+        numChangedModules += patchDelta(jsonReader, mPreModules);
+      } else if (name.equals("post")) {
+        numChangedModules += patchDelta(jsonReader, mPostModules);
+      } else if (name.equals("delta")) {
+        numChangedModules += patchDelta(jsonReader, mDeltaModules);
+      } else {
+        jsonReader.skipValue();
+      }
+    }
+
+    jsonReader.endObject();
+    jsonReader.close();
+
+    if (numChangedModules == 0) {
+      // If we receive an empty delta, we don't need to save the file again (it'll have the
+      // same content).
+      return false;
+    }
+
+    FileOutputStream fileOutputStream = new FileOutputStream(outputFile);
+
+    try {
+      for (byte[] code : mPreModules.values()) {
+        fileOutputStream.write(code);
+        fileOutputStream.write('\n');
+      }
+
+      for (byte[] code : mDeltaModules.values()) {
+        fileOutputStream.write(code);
+        fileOutputStream.write('\n');
+      }
+
+      for (byte[] code : mPostModules.values()) {
+        fileOutputStream.write(code);
+        fileOutputStream.write('\n');
+      }
+    } finally {
+      fileOutputStream.flush();
+      fileOutputStream.close();
+    }
+
+    return true;
+  }
+
+  private static int patchDelta(JsonReader jsonReader, LinkedHashMap<Number, byte[]> map)
+    throws IOException {
+    jsonReader.beginArray();
+
+    int numModules = 0;
+    while (jsonReader.hasNext()) {
+      jsonReader.beginArray();
+
+      int moduleId = jsonReader.nextInt();
+
+      if (jsonReader.peek() == JsonToken.NULL) {
+        jsonReader.skipValue();
+        map.remove(moduleId);
+      } else {
+        map.put(moduleId, jsonReader.nextString().getBytes());
+      }
+
+      jsonReader.endArray();
+      numModules++;
+    }
+
+    jsonReader.endArray();
+
+    return numModules;
+  }
+}

ReactAndroid/src/main/java/com/facebook/react/devsupport/BundleDownloader.java

@@ -9,19 +9,14 @@
 
 package com.facebook.react.devsupport;
 
-import android.util.JsonReader;
-import android.util.JsonToken;
 import android.util.Log;
 import com.facebook.common.logging.FLog;
 import com.facebook.infer.annotation.Assertions;
 import com.facebook.react.common.DebugServerException;
 import com.facebook.react.common.ReactConstants;
 import com.facebook.react.devsupport.interfaces.DevBundleDownloadListener;
 import java.io.File;
-import java.io.FileOutputStream;
 import java.io.IOException;
-import java.io.InputStreamReader;
-import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -47,11 +42,8 @@ public class BundleDownloader {
 
   private final OkHttpClient mClient;
 
-  private final LinkedHashMap<Number, byte[]> mPreModules = new LinkedHashMap<>();
-  private final LinkedHashMap<Number, byte[]> mDeltaModules = new LinkedHashMap<>();
-  private final LinkedHashMap<Number, byte[]> mPostModules = new LinkedHashMap<>();
+  private final BundleDeltaClient mBundleDeltaClient = new BundleDeltaClient();
 
-  private @Nullable String mDeltaId;
   private @Nullable Call mDownloadBundleFromURLCall;
 
   public static class BundleInfo {
@@ -110,15 +102,9 @@ public void downloadBundleFromURL(
       final String bundleURL,
       final @Nullable BundleInfo bundleInfo) {
 
-    String finalUrl = bundleURL;
-
-    if (isDeltaUrl(bundleURL) && mDeltaId != null) {
-      finalUrl += "&deltaBundleId=" + mDeltaId;
-    }
-
     final Request request =
         new Request.Builder()
-            .url(finalUrl)
+            .url(mBundleDeltaClient.toDeltaUrl(bundleURL))
             // FIXME: there is a bug that makes MultipartStreamReader to never find the end of the
             // multipart message. This temporarily disables the multipart mode to work around it,
             // but
@@ -253,11 +239,11 @@ private void processBundleResult(
 
     boolean bundleUpdated;
 
-    if (isDeltaUrl(url)) {
+    if (BundleDeltaClient.isDeltaUrl(url)) {
       // If the bundle URL has the delta extension, we need to use the delta patching logic.
-      bundleUpdated = storeDeltaInFile(body, tmpFile);
+      bundleUpdated = mBundleDeltaClient.storeDeltaInFile(body, tmpFile);
     } else {
-      resetDeltaCache();
+      mBundleDeltaClient.reset();
       bundleUpdated = storePlainJSInFile(body, tmpFile);
     }
 
@@ -286,101 +272,6 @@ private static boolean storePlainJSInFile(BufferedSource body, File outputFile)
     return true;
   }
 
-  private synchronized boolean storeDeltaInFile(BufferedSource body, File outputFile) throws IOException {
-
-    JsonReader jsonReader = new JsonReader(new InputStreamReader(body.inputStream()));
-
-    jsonReader.beginObject();
-
-    int numChangedModules = 0;
-
-    while (jsonReader.hasNext()) {
-      String name = jsonReader.nextName();
-      if (name.equals("id")) {
-        mDeltaId = jsonReader.nextString();
-      } else if (name.equals("pre")) {
-        numChangedModules += patchDelta(jsonReader, mPreModules);
-      } else if (name.equals("post")) {
-        numChangedModules += patchDelta(jsonReader, mPostModules);
-      } else if (name.equals("delta")) {
-        numChangedModules += patchDelta(jsonReader, mDeltaModules);
-      } else {
-        jsonReader.skipValue();
-      }
-    }
-
-    jsonReader.endObject();
-    jsonReader.close();
-
-    if (numChangedModules == 0) {
-      // If we receive an empty delta, we don't need to save the file again (it'll have the
-      // same content).
-      return false;
-    }
-
-    FileOutputStream fileOutputStream = new FileOutputStream(outputFile);
-
-    try {
-      for (byte[] code : mPreModules.values()) {
-        fileOutputStream.write(code);
-        fileOutputStream.write('\n');
-      }
-
-      for (byte[] code : mDeltaModules.values()) {
-        fileOutputStream.write(code);
-        fileOutputStream.write('\n');
-      }
-
-      for (byte[] code : mPostModules.values()) {
-        fileOutputStream.write(code);
-        fileOutputStream.write('\n');
-      }
-    } finally {
-      fileOutputStream.flush();
-      fileOutputStream.close();
-    }
-
-    return true;
-  }
-
-  private static int patchDelta(JsonReader jsonReader, LinkedHashMap<Number, byte[]> map)
-      throws IOException {
-    jsonReader.beginArray();
-
-    int numModules = 0;
-    while (jsonReader.hasNext()) {
-      jsonReader.beginArray();
-
-      int moduleId = jsonReader.nextInt();
-
-      if (jsonReader.peek() == JsonToken.NULL) {
-        jsonReader.skipValue();
-        map.remove(moduleId);
-      } else {
-        map.put(moduleId, jsonReader.nextString().getBytes());
-      }
-
-      jsonReader.endArray();
-      numModules++;
-    }
-
-    jsonReader.endArray();
-
-    return numModules;
-  }
-
-  private void resetDeltaCache() {
-    mDeltaId = null;
-
-    mDeltaModules.clear();
-    mPreModules.clear();
-    mPostModules.clear();
-  }
-
-  private static boolean isDeltaUrl(String bundleUrl) {
-    return bundleUrl.indexOf(".delta?") != -1;
-  }
-
   private static void populateBundleInfo(String url, Headers headers, BundleInfo bundleInfo) {
     bundleInfo.mUrl = url;