Issue 5568 - Improve string handling by splitting read strings into only ASCII and non-ASCII strings

src/FileSystemJsObject.cpp

Index: src/FileSystemJsObject.cpp
diff --git a/src/FileSystemJsObject.cpp b/src/FileSystemJsObject.cpp
index 37e1627c7c1ab0797add282ada968c940f04e1af..feb2358fd17b59954bdff5688f23a7cb51148f8f 100644
--- a/src/FileSystemJsObject.cpp
+++ b/src/FileSystemJsObject.cpp
@@ -24,6 +24,7 @@
 #include "FileSystemJsObject.h"
 #include "JsContext.h"
 #include "Utils.h"
+#include "JsError.h"
 #include <AdblockPlus/Platform.h>
 
 using namespace AdblockPlus;
@@ -63,6 +64,86 @@ namespace
       });
   }
 
+  inline bool CReturnOrLineFeed(char c)

[hub, 2017/08/30 21:13:31]

nit': I would name this function "IsEndOfLine()"

[sergei, 2017/08/31 10:45:26]

I am actually also not glad with the name of this function. I will definitely
add "Is" prefix.
What about IsLineTerminator and SkipLineTerminators and AdvanceToLineTerminator?

[hub, 2017/08/31 12:59:43]

"End of line" or EOL is often used through the UNIX man pages. "Line break" can
be used in the same context but I have seen it more for word processor. "Line
Terminator" I haven't seen that. Hence my choice of words.

[sergei, 2017/08/31 13:21:44]

agree.

+  {
+    return c == 10 || c == 13;
+  }
+
+  inline StringBuffer::const_iterator SkipCReturnAndLineFeed(StringBuffer::const_iterator ii, StringBuffer::const_iterator end)

[hub, 2017/08/30 21:13:30]

and this one SkipEndOfLine()

+  {
+    while (ii != end && CReturnOrLineFeed(*ii))
+      ++ii;
+    return ii;
+  }
+
+  inline StringBuffer::const_iterator AdvanceUntilCReturnOrLineFeed(StringBuffer::const_iterator ii, StringBuffer::const_iterator end)

[hub, 2017/08/30 21:13:31]

And this one AdvanceToEndOfLine()

But this is not really blocking. I find it clearer.

+  {
+    while (ii != end && !CReturnOrLineFeed(*ii))
+      ++ii;
+    return ii;
+  }
+
+  void ReadFromFileCallback(const v8::FunctionCallbackInfo<v8::Value>& arguments)
+  {
+    AdblockPlus::JsEnginePtr jsEngine = AdblockPlus::JsEngine::FromArguments(arguments);
+    AdblockPlus::JsValueList converted = jsEngine->ConvertArguments(arguments);
+
+    v8::Isolate* isolate = arguments.GetIsolate();
+    if (converted.size() != 3)
+      return ThrowExceptionInJS(isolate, "_fileSystem.readFromFile requires 3 parameters");
+    if (!converted[1].IsFunction())
+      return ThrowExceptionInJS(isolate, "Second argument to _fileSystem.readFromFile must be a function (listener callback)");
+    if (!converted[2].IsFunction())
+      return ThrowExceptionInJS(isolate, "Third argument to _fileSystem.readFromFile must be a function (done callback)");
+
+    JsValueList values;
+    values.push_back(converted[1]);
+    values.push_back(converted[2]);
+    auto weakCallback = jsEngine->StoreJsValues(values);
+    std::weak_ptr<JsEngine> weakJsEngine = jsEngine;
+    jsEngine->GetPlatform().GetFileSystem().Read(converted[0].AsString(),
+      [weakJsEngine, weakCallback]
+    (IFileSystem::IOBuffer&& content, const std::string& error)
+    {
+      auto jsEngine = weakJsEngine.lock();
+      if (!jsEngine)
+        return;
+
+      const JsContext context(*jsEngine);
+
+      auto jsValues = jsEngine->TakeJsValues(weakCallback);
+      if (!error.empty())
+      {
+        jsValues[1].Call(jsEngine->NewValue(error));
+        return;
+      }
+
+      auto processFunc = jsValues[0].UnwrapValue().As<v8::Function>();
+
+      auto globalContext = context.GetV8Context()->Global();
+      if (!globalContext->IsObject())
+        throw std::runtime_error("`this` pointer has to be an object");
+
+      const v8::TryCatch tryCatch;
+
+      const auto contentEnd = content.cend();
+      auto stringBegin = SkipCReturnAndLineFeed(content.begin(), contentEnd);
+      do
+      {
+        auto stringEnd = AdvanceUntilCReturnOrLineFeed(stringBegin, contentEnd);
+        auto jsLine = Utils::StringBufferToV8String(jsEngine->GetIsolate(), StringBuffer(stringBegin, stringEnd)).As<v8::Value>();
+        processFunc->Call(globalContext, 1, &jsLine);
+        if (tryCatch.HasCaught())
+        {
+          jsValues[1].Call(jsEngine->NewValue(JsError::ExceptionToString(tryCatch.Exception(), tryCatch.Message())));
+          return;
+        }
+        stringBegin = SkipCReturnAndLineFeed(stringEnd, contentEnd);
+      } while (stringBegin != contentEnd);
+      jsValues[1].Call();
+    });
+  }
+
   void WriteCallback(const v8::FunctionCallbackInfo<v8::Value>& arguments)
   {
     AdblockPlus::JsEnginePtr jsEngine = AdblockPlus::JsEngine::FromArguments(arguments);
@@ -198,6 +279,7 @@ namespace
 JsValue& FileSystemJsObject::Setup(JsEngine& jsEngine, JsValue& obj)
 {
   obj.SetProperty("read", jsEngine.NewCallback(::ReadCallback));
+  obj.SetProperty("readFromFile", jsEngine.NewCallback(::ReadFromFileCallback));
   obj.SetProperty("write", jsEngine.NewCallback(::WriteCallback));
   obj.SetProperty("move", jsEngine.NewCallback(::MoveCallback));
   obj.SetProperty("remove", jsEngine.NewCallback(::RemoveCallback));