Allow streaming io objects into Gitaly

This allows us to set the encoding of an IO passed without reading it
into memory.

This is useful if we want to stream files into Gitaly. Like we do when
uploading a new file to the repository.

app/controllers/projects/blob_controller.rb

@@ -172,8 +172,7 @@ class Projects::BlobController < Projects::ApplicationController
       end
 
     if params[:file].present?
-      params[:content] = Base64.encode64(params[:file].read)
-      params[:encoding] = 'base64'
+      params[:content] = params[:file]
     end
 
     @commit_params = {

lib/gitlab/encoding_helper.rb

@@ -76,8 +76,11 @@ module Gitlab
       str.dup.force_encoding(Encoding::ASCII_8BIT)
     end
 
-    def binary_stringio(str)
-      StringIO.new(str.freeze || '').tap { |io| io.set_encoding(Encoding::ASCII_8BIT) }
+    def binary_io(str_or_io)
+      io = str_or_io.to_io.dup if str_or_io.respond_to?(:to_io)
+      io ||= StringIO.new(str_or_io.to_s.freeze)
+
+      io.tap { |io| io.set_encoding(Encoding::ASCII_8BIT) }
     end
 
     private

lib/gitlab/gitaly_client/conflicts_service.rb

@@ -37,7 +37,7 @@ module Gitlab
       end
 
       def resolve_conflicts(target_repository, resolution, source_branch, target_branch)
-        reader = binary_stringio(resolution.files.to_json)
+        reader = binary_io(resolution.files.to_json)
 
         req_enum = Enumerator.new do |y|
           header = resolve_conflicts_request_header(target_repository, resolution, source_branch, target_branch)

lib/gitlab/gitaly_client/operation_service.rb

@@ -294,7 +294,7 @@ module Gitlab
               action: Gitaly::UserCommitFilesAction.new(header: action_header)
             )
 
-            reader = binary_stringio(action[:content])
+            reader = binary_io(action[:content])
 
             until reader.eof?
               chunk = reader.read(MAX_MSG_SIZE)
@@ -327,7 +327,7 @@ module Gitlab
           user: Gitlab::Git::User.from_gitlab(user).to_gitaly,
           target_branch: encode_binary(branch_name)
         )
-        reader = binary_stringio(patches)
+        reader = binary_io(patches)
 
         chunks = Enumerator.new do |chunk|
           chunk.yield Gitaly::UserApplyPatchRequest.new(header: header)

lib/gitlab/gitaly_client/wiki_service.rb

@@ -22,7 +22,7 @@ module Gitlab
           commit_details: gitaly_commit_details(commit_details)
         )
 
-        strio = binary_stringio(content)
+        strio = binary_io(content)
 
         enum = Enumerator.new do |y|
           until strio.eof?
@@ -49,7 +49,7 @@ module Gitlab
           commit_details: gitaly_commit_details(commit_details)
         )
 
-        strio = binary_stringio(content)
+        strio = binary_io(content)
 
         enum = Enumerator.new do |y|
           until strio.eof?

spec/lib/gitlab/encoding_helper_spec.rb

@@ -189,14 +189,23 @@ describe Gitlab::EncodingHelper do
     end
   end
 
-  describe '#binary_stringio' do
+  describe '#binary_io' do
     it 'does not mutate the original string encoding' do
       test = 'my-test'
 
-      io_stream = ext_class.binary_stringio(test)
+      io_stream = ext_class.binary_io(test)
 
       expect(io_stream.external_encoding.name).to eq('ASCII-8BIT')
       expect(test.encoding.name).to eq('UTF-8')
     end
+
+    it 'returns a copy of the IO with the correct encoding' do
+      test = fixture_file_upload('spec/fixtures/doc_sample.txt').to_io
+
+      io_stream = ext_class.binary_io(test)
+
+      expect(io_stream.external_encoding.name).to eq('ASCII-8BIT')
+      expect(test).not_to eq(io_stream)
+    end
   end
 end