[Reproducer] Add LoadBuffer<> helper (NFC)

Introduce a helper method named LoadBuffer in the Loader to abstract
reading a reproducer file from disk.

llvm-svn: 375060

Author: JDevlieghere

lldb/include/lldb/Utility/Reproducer.h

@@ -302,6 +302,15 @@ class Loader final {
     return GetRoot().CopyByAppendingPathComponent(T::file);
   }
 
+  template <typename T> llvm::Expected<std::string> LoadBuffer() {
+    FileSpec file = GetFile<typename T::Info>();
+    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> buffer =
+        llvm::vfs::getRealFileSystem()->getBufferForFile(file.GetPath());
+    if (!buffer)
+      return llvm::errorCodeToError(buffer.getError());
+    return (*buffer)->getBuffer().str();
+  }
+
   llvm::Error LoadIndex();
 
   const FileSpec &GetRoot() const { return m_root; }

lldb/source/Commands/CommandObjectReproducer.cpp

@@ -265,19 +265,12 @@ class CommandObjectReproducerDump : public CommandObjectParsed {
       return true;
     }
     case eReproducerProviderVersion: {
-      FileSpec version_file = loader->GetFile<VersionProvider::Info>();
-
-      // Load the version info into a buffer.
-      ErrorOr<std::unique_ptr<MemoryBuffer>> buffer =
-          vfs::getRealFileSystem()->getBufferForFile(version_file.GetPath());
-      if (!buffer) {
-        SetError(result, errorCodeToError(buffer.getError()));
+      Expected<std::string> version = loader->LoadBuffer<VersionProvider>();
+      if (!version) {
+        SetError(result, version.takeError());
         return false;
       }
-
-      // Return the version string.
-      StringRef version = (*buffer)->getBuffer();
-      result.AppendMessage(version.str());
+      result.AppendMessage(*version);
       result.SetStatus(eReturnStatusSuccessFinishResult);
       return true;
     }