Fix nullsafe FIXMEs for BlobModule.java and mark nullsafe (#50366)

Summary:
Pull Request resolved: #50366

Gone trough all the FIXMEs added in the previous diff by the nullsafe tool, marked the class as nullsafe and ensured no remaining violations.
Changelog: [Android][Fixed] Made BlobModule.java nullsafe

Reviewed By: cortinico

Differential Revision: D71979598

fbshipit-source-id: bbef5548d05e0b77ea03cf72f41a384fe7294d59

Author: GijsWeterings

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/blob/BlobModule.java

@@ -14,6 +14,8 @@
 import android.webkit.MimeTypeMap;
 import androidx.annotation.Nullable;
 import com.facebook.fbreact.specs.NativeBlobModuleSpec;
+import com.facebook.infer.annotation.Assertions;
+import com.facebook.infer.annotation.Nullsafe;
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.ReactApplicationContext;
@@ -41,6 +43,7 @@
 import okhttp3.ResponseBody;
 import okio.ByteString;
 
+@Nullsafe(Nullsafe.Mode.LOCAL)
 @ReactModule(name = NativeBlobModuleSpec.NAME)
 public class BlobModule extends NativeBlobModuleSpec {
 
@@ -106,18 +109,21 @@ public boolean supports(ReadableMap data) {
         @Override
         public RequestBody toRequestBody(ReadableMap data, String contentType) {
           String type = contentType;
-          // NULLSAFE_FIXME[Nullable Dereference]
-          if (data.hasKey("type") && !data.getString("type").isEmpty()) {
+          if (data.hasKey("type")
+              && data.getString("type") != null
+              && !data.getString("type").isEmpty()) {
             type = data.getString("type");
           }
           if (type == null) {
             type = "application/octet-stream";
           }
           ReadableMap blob = data.getMap("blob");
-          // NULLSAFE_FIXME[Nullable Dereference]
-          String blobId = blob.getString("blobId");
-          // NULLSAFE_FIXME[Parameter Not Nullable, Nullable Dereference]
-          byte[] bytes = resolve(blobId, blob.getInt("offset"), blob.getInt("size"));
+
+          // supports() ensures blob is not null, but for nullability we have to check it
+          Assertions.assertNotNull(blob, "Blob is null even though supports() returned true");
+
+          byte[] bytes =
+              resolve(blob.getString("blobId"), blob.getInt("offset"), blob.getInt("size"));
 
           return RequestBody.create(MediaType.parse(type), bytes);
         }
@@ -151,8 +157,7 @@ public void initialize() {
   }
 
   @Override
-  // NULLSAFE_FIXME[Inconsistent Subclass Return Annotation]
-  public @Nullable Map<String, Object> getTypedExportedConstants() {
+  public Map<String, Object> getTypedExportedConstants() {
     // The application can register BlobProvider as a ContentProvider so that blobs are resolvable.
     // If it does, it needs to tell us what authority was used via this string resource.
     Resources resources = getReactApplicationContext().getResources();
@@ -205,11 +210,10 @@ public void remove(String blobId) {
     if (sizeParam != null) {
       size = Integer.parseInt(sizeParam, 10);
     }
-    // NULLSAFE_FIXME[Parameter Not Nullable]
     return resolve(blobId, offset, size);
   }
 
-  public @Nullable byte[] resolve(String blobId, int offset, int size) {
+  public @Nullable byte[] resolve(@Nullable String blobId, int offset, int size) {
     synchronized (mBlobs) {
       byte[] data = mBlobs.get(blobId);
       if (data == null) {
@@ -226,7 +230,6 @@ public void remove(String blobId) {
   }
 
   public @Nullable byte[] resolve(ReadableMap blob) {
-    // NULLSAFE_FIXME[Parameter Not Nullable]
     return resolve(blob.getString("blobId"), blob.getInt("offset"), blob.getInt("size"));
   }
 
@@ -273,9 +276,8 @@ private byte[] getBytesFromUri(Uri contentUri) throws IOException {
     }
   }
 
-  private String getNameFromUri(Uri contentUri) {
+  private @Nullable String getNameFromUri(Uri contentUri) {
     if ("file".equals(contentUri.getScheme())) {
-      // NULLSAFE_FIXME[Return Not Nullable]
       return contentUri.getLastPathSegment();
     }
     String[] projection = {MediaStore.MediaColumns.DISPLAY_NAME};
@@ -286,14 +288,12 @@ private String getNameFromUri(Uri contentUri) {
     if (metaCursor != null) {
       try {
         if (metaCursor.moveToFirst()) {
-          // NULLSAFE_FIXME[Return Not Nullable]
           return metaCursor.getString(0);
         }
       } finally {
         metaCursor.close();
       }
     }
-    // NULLSAFE_FIXME[Return Not Nullable]
     return contentUri.getLastPathSegment();
   }
 
@@ -321,15 +321,13 @@ private String getMimeTypeFromUri(Uri contentUri) {
     return type;
   }
 
-  private WebSocketModule getWebSocketModule(String reason) {
+  private @Nullable WebSocketModule getWebSocketModule(String reason) {
     ReactApplicationContext reactApplicationContext = getReactApplicationContextIfActiveOrWarn();
 
     if (reactApplicationContext != null) {
-      // NULLSAFE_FIXME[Return Not Nullable]
       return reactApplicationContext.getNativeModule(WebSocketModule.class);
     }
 
-    // NULLSAFE_FIXME[Return Not Nullable]
     return null;
   }
 
@@ -340,11 +338,9 @@ public void addNetworkingHandler() {
     if (reactApplicationContext != null) {
       NetworkingModule networkingModule =
           reactApplicationContext.getNativeModule(NetworkingModule.class);
-      // NULLSAFE_FIXME[Nullable Dereference]
+      Assertions.assertNotNull(networkingModule, "NetworkingModule is null");
       networkingModule.addUriHandler(mNetworkingUriHandler);
-      // NULLSAFE_FIXME[Nullable Dereference]
       networkingModule.addRequestBodyHandler(mNetworkingRequestBodyHandler);
-      // NULLSAFE_FIXME[Nullable Dereference]
       networkingModule.addResponseHandler(mNetworkingResponseHandler);
     }
   }
@@ -378,14 +374,10 @@ public void sendOverSocket(ReadableMap blob, double idDouble) {
     WebSocketModule webSocketModule = getWebSocketModule("sendOverSocket");
 
     if (webSocketModule != null) {
-      // NULLSAFE_FIXME[Parameter Not Nullable]
       byte[] data = resolve(blob.getString("blobId"), blob.getInt("offset"), blob.getInt("size"));
 
       if (data != null) {
         webSocketModule.sendBinary(ByteString.of(data), id);
-      } else {
-        // NULLSAFE_FIXME[Parameter Not Nullable]
-        webSocketModule.sendBinary((ByteString) null, id);
       }
     }
   }
@@ -396,24 +388,24 @@ public void createFromParts(ReadableArray parts, String blobId) {
     ArrayList<byte[]> partList = new ArrayList<>(parts.size());
     for (int i = 0; i < parts.size(); i++) {
       ReadableMap part = parts.getMap(i);
-      // NULLSAFE_FIXME[Nullable Dereference]
-      switch (part.getString("type")) {
+      Assertions.assertNotNull(part, "Blob part is null");
+      String type = part.getString("type");
+      Assertions.assertNotNull(type, "Invalid type for blob: null");
+      switch (type) {
         case "blob":
-          // NULLSAFE_FIXME[Nullable Dereference]
           ReadableMap blob = part.getMap("data");
-          // NULLSAFE_FIXME[Nullable Dereference]
+          Assertions.assertNotNull(blob, "Blob is null");
           totalBlobSize += blob.getInt("size");
-          // NULLSAFE_FIXME[Parameter Not Nullable]
           partList.add(i, resolve(blob));
           break;
         case "string":
-          // NULLSAFE_FIXME[Nullable Dereference]
-          byte[] bytes = part.getString("data").getBytes(Charset.forName("UTF-8"));
+          String data = part.getString("data");
+          Assertions.assertNotNull(data, "Data is null");
+          byte[] bytes = data.getBytes(Charset.forName("UTF-8"));
           totalBlobSize += bytes.length;
           partList.add(i, bytes);
           break;
         default:
-          // NULLSAFE_FIXME[Nullable Dereference]
           throw new IllegalArgumentException("Invalid type for blob: " + part.getString("type"));
       }
     }