Support IO.copy_stream from a pipe IO instance.

kernel/common/io19.rb

@@ -274,7 +274,11 @@ def run
       @from.ensure_open_and_readable
       @to.ensure_open_and_writable
 
-      saved_pos = @from.pos if @from_io
+      if @from_io && !@from.pipe?
+        saved_pos = @from.pos
+      else
+        saved_pos = 0
+      end
 
       @from.seek @offset, IO::SEEK_CUR if @offset
 
@@ -410,6 +414,8 @@ def initialize(fd, mode=undefined, options=undefined)
         @external = Encoding.default_external
       end
     end
+
+    @pipe = false
   end
 
   private :initialize
@@ -945,6 +951,14 @@ def close_on_exec?
     (fcntl(F_GETFD) & FD_CLOEXEC) != 0
   end
 
+  def pipe=(v)
+    @pipe = !!v
+  end
+
+  def pipe?
+    @pipe
+  end
+
   def self.pipe(external=nil, internal=nil, options=nil)
     lhs = allocate
     rhs = allocate
@@ -961,6 +975,9 @@ def self.pipe(external=nil, internal=nil, options=nil)
     lhs.sync = true
     rhs.sync = true
 
+    lhs.pipe = true
+    rhs.pipe = true
+
     if block_given?
       begin
         yield lhs, rhs

spec/ruby/core/io/copy_stream_spec.rb

@@ -20,11 +20,6 @@
       @to_name.should have_data("Line one")
     end
 
-    it "copies only length bytes from the offset" do
-      IO.copy_stream(@object.from, @to_name, 8, 4).should == 8
-      @to_name.should have_data(" one\n\nLi")
-    end
-
     it "calls #to_path to convert on object to a file name" do
       obj = mock("io_copy_stream_to")
       obj.should_receive(:to_path).and_return(@to_name)
@@ -41,12 +36,19 @@
     end
   end
 
+  describe :io_copy_stream_to_file_with_offset, :shared => true do
+    it "copies only length bytes from the offset" do
+      IO.copy_stream(@object.from, @to_name, 8, 4).should == 8
+      @to_name.should have_data(" one\n\nLi")
+    end
+  end
+
   describe :io_copy_stream_to_io, :shared => true do
     it "copies the entire IO contents to the IO" do
       IO.copy_stream(@object.from, @to_io)
       @to_name.should have_data(@content)
       IO.copy_stream(@from_bigfile, @to_io)
-      @to_io.should have_data(@content + @content_bigfile)
+      @to_name.should have_data(@content + @content_bigfile)
     end
 
     it "returns the number of bytes copied" do
@@ -67,7 +69,7 @@
 
     it "raises an IOError if the destination IO is not open for writing" do
       @to_io.close
-      @to_io = File.open @to_name, "r"
+      @to_io = new_io @to_name, "r"
       lambda { IO.copy_stream @object.from, @to_io }.should raise_error(IOError)
     end
 
@@ -80,7 +82,9 @@
       IO.copy_stream(@object.from, @to_io, 8).should == 8
       @to_name.should have_data("Line one")
     end
+  end
 
+  describe :io_copy_stream_to_io_with_offset, :shared => true do
     it "copies only length bytes from the offset" do
       IO.copy_stream(@object.from, @to_io, 8, 4).should == 8
       @to_name.should have_data(" one\n\nLi")
@@ -107,7 +111,7 @@
 
     describe "from an IO" do
       before :each do
-        @from_io = File.open @from_name, "rb"
+        @from_io = new_io @from_name, "rb"
         IOSpecs::CopyStream.from = @from_io
       end
 
@@ -117,7 +121,7 @@
 
       it "raises an IOError if the source IO is not open for reading" do
         @from_io.close
-        @from_io = File.open @from_name, "a"
+        @from_io = new_io @from_name, "a"
         lambda { IO.copy_stream @from_io, @to_name }.should raise_error(IOError)
       end
 
@@ -140,18 +144,20 @@
 
       describe "to a file name" do
         it_behaves_like :io_copy_stream_to_file, nil, IOSpecs::CopyStream
+        it_behaves_like :io_copy_stream_to_file_with_offset, nil, IOSpecs::CopyStream
       end
 
       describe "to an IO" do
         before :each do
-          @to_io = File.open @to_name, "wb"
+          @to_io = new_io @to_name, "wb"
         end
 
         after :each do
           @to_io.close
         end
 
         it_behaves_like :io_copy_stream_to_io, nil, IOSpecs::CopyStream
+        it_behaves_like :io_copy_stream_to_io_with_offset, nil, IOSpecs::CopyStream
       end
     end
 
@@ -175,13 +181,51 @@
         lambda { IO.copy_stream(obj, @to_name) }.should raise_error(TypeError)
       end
 
+      describe "to a file name" do
+        it_behaves_like :io_copy_stream_to_file, nil, IOSpecs::CopyStream
+        it_behaves_like :io_copy_stream_to_file_with_offset, nil, IOSpecs::CopyStream
+      end
+
+      describe "to an IO" do
+        before :each do
+          @to_io = new_io @to_name, "wb"
+        end
+
+        after :each do
+          @to_io.close
+        end
+
+        it_behaves_like :io_copy_stream_to_io, nil, IOSpecs::CopyStream
+        it_behaves_like :io_copy_stream_to_io_with_offset, nil, IOSpecs::CopyStream
+      end
+    end
+
+    describe "from a pipe IO" do
+      before :each do
+        @from_io = IOSpecs.pipe_fixture(@content)
+        IOSpecs::CopyStream.from = @from_io
+      end
+
+      after :each do
+        @from_io.close
+      end
+
+      it "does not close the source IO" do
+        IO.copy_stream(@from_io, @to_name)
+        @from_io.closed?.should be_false
+      end
+
+      it "raises an error when an offset is specified" do
+        lambda { IO.copy_stream(@from_io, @to_name, 8, 4) }.should raise_error(Errno::ESPIPE)
+      end
+
       describe "to a file name" do
         it_behaves_like :io_copy_stream_to_file, nil, IOSpecs::CopyStream
       end
 
       describe "to an IO" do
         before :each do
-          @to_io = File.open @to_name, "wb"
+          @to_io = new_io @to_name, "wb"
         end
 
         after :each do

spec/ruby/core/io/fixtures/classes.rb

@@ -121,6 +121,15 @@ def self.closed_io
     io.close
     io
   end
+
+  # Creates a pipe-based IO fixture containing the specified
+  # contents
+  def self.pipe_fixture(content)
+    source, sink = IO.pipe
+    sink.write content
+    sink.close
+    source
+  end
 
   # Defines +method+ on +obj+ using the provided +block+. This
   # special helper is needed for e.g. IO.open specs to avoid