Issue 6477 - separate done and error callbacks in IFileSystem::Read

test/FileSystemJsObject.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 23 matching lines @@
     std::string movedTo;
     std::string removedFile;
     mutable std::string statFile;
     bool statExists;
     int statLastModified;
 
     MockFileSystem() : success(true)
     {
     }
 
-    void Read(const std::string& fileName, const ReadCallback& callback) const override
+    void Read(const std::string& fileName, const ReadCallback& callback, const Callback& errorCallback) const override
     {
-      if (!success)
-      {
-        callback(IOBuffer(), "Unable to read " + fileName);
-        return;
-      }
-      callback(IOBuffer(contentToRead), "");
+      if (success)
+        try
+        {
+          callback(IOBuffer(contentToRead));
+        }
+        catch (const std::exception& ex)
+        {
+          errorCallback(ex.what());
+        }
+      else
+        errorCallback("Unable to read " + fileName);
     }
 
     void Write(const std::string& fileName, const IOBuffer& data,
                const Callback& callback) override
     {
       if (!success)
       {
         callback("Unable to write to " + fileName);
         return;
       }
@@ skipping 39 matching lines @@
         result.exists = statExists;
         result.lastModified = statLastModified;
       }
       callback(result, error);
     }
   };
 
   void ReadFile(AdblockPlus::JsEngine& jsEngine, std::string& content,
                 std::string& error)
   {
-    jsEngine.Evaluate("let result; _fileSystem.read('', function(r) {result = r})");
+    jsEngine.Evaluate("let result = {}; _fileSystem.read('', function(r) {result.content = r.content;}, function(r) {result.error = r.error;})");
     content = jsEngine.Evaluate("result.content").AsString();
     error = jsEngine.Evaluate("result.error").AsString();
   }
 
   class FileSystemJsObjectTest : public BaseJsTest
   {
   protected:
     MockFileSystem* mockFileSystem;
 
     void SetUp()
@@ skipping 22 matching lines @@
   ASSERT_ANY_THROW(GetJsEngine().Evaluate("_fileSystem.read('', '')"));
 }
 
 TEST_F(FileSystemJsObjectTest, ReadError)
 {
   mockFileSystem->success = false;
   std::string content;
   std::string error;
   ReadFile(GetJsEngine(), content, error);
   ASSERT_NE("", error);
-  ASSERT_EQ("", content);
+  ASSERT_EQ("undefined", content);
 }
 
 TEST_F(FileSystemJsObjectTest, Write)
 {
   GetJsEngine().Evaluate("let error = true; _fileSystem.write('foo', 'bar', function(e) {error = e})");
   ASSERT_EQ("foo", mockFileSystem->lastWrittenFile);
   ASSERT_EQ((AdblockPlus::IFileSystem::IOBuffer{'b', 'a', 'r'}),
             mockFileSystem->lastWrittenContent);
   ASSERT_TRUE(GetJsEngine().Evaluate("error").IsUndefined());
 }
@@ skipping 104 matching lines @@
         }
         else
         {
           ASSERT_EQ(1u, jsArgs.size());
           EXPECT_TRUE(jsArgs[0].IsString());
           EXPECT_FALSE(jsArgs[0].AsString().empty());
         }
       });
       jsEngine.Evaluate(R"js(_fileSystem.readFromFile("foo",
   (line) => _triggerEvent("onLine", line),
-  (error) =>
-  {
-    if (error)
-      _triggerEvent("onDone", error);
-    else
-      _triggerEvent("onDone");
-});)js");
+  () =>_triggerEvent("onDone"),
+  (error) => _triggerEvent("onDone", error));
+)js");
       EXPECT_TRUE(isOnDoneCalled);
     }
 
     void readFromFile_Lines(const std::string& content, const Lines& expected)
     {
       mockFileSystem->contentToRead.assign(content.begin(), content.end());
       std::vector<std::string> readLines;
       readFromFile([&readLines](const std::string& line)
         {
           readLines.emplace_back(line);
@@ skipping 89 matching lines @@
 let onLineCounter = 0;
 _fileSystem.readFromFile("foo",
   (line) =>
   {
     if (onLineCounter++ == 2)
     {
       throw new Error("my-error");
     }
     _triggerEvent("onLine", line);
   },
-  (error) =>
-  {
-    if (error)
-      _triggerEvent("onDone", error);
-    else
-      _triggerEvent("onDone");
-});)js");
+  () => _triggerEvent("onDone"),
+  (error) => _triggerEvent("onDone", error));
+)js");
   EXPECT_EQ(2u, readLines.size());
   EXPECT_EQ("Error: my-error at undefined:8", error);
 }