[ruby/openssl] Add SSLSocket#readbyte

Companion to getbyte but raise EOFError
Similar to https://github.com/ruby/openssl/pull/438

https://github.com/ruby/openssl/commit/c40f70711a

ext/openssl/lib/openssl/buffering.rb

@@ -107,6 +107,12 @@ module OpenSSL::Buffering
     read(1)&.ord
   end
 
+  # Get the next 8bit byte. Raises EOFError on EOF
+  def readbyte
+    raise EOFError if eof?
+    getbyte
+  end
+
   ##
   # Reads _size_ bytes from the stream.  If _buf_ is provided it must
   # reference a string which will receive the data.

test/openssl/test_pair.rb

@@ -101,6 +101,27 @@ module OpenSSL::TestPairM
     }
   end
 
+  def test_getbyte
+    ssl_pair {|s1, s2|
+      s1 << "a"
+      assert_equal(97, s2.getbyte)
+    }
+  end
+
+  def test_readbyte
+    ssl_pair {|s1, s2|
+      s1 << "b"
+      assert_equal(98, s2.readbyte)
+    }
+  end
+
+  def test_readbyte_eof
+    ssl_pair {|s1, s2|
+      s2.close
+      assert_raise(EOFError) { s1.readbyte }
+    }
+  end
+
   def test_gets
     ssl_pair {|s1, s2|
       s1 << "abc\n\n$def123ghi"

test/openssl/test_ssl.rb

@@ -248,6 +248,19 @@ class OpenSSL::TestSSL < OpenSSL::SSLTestCase
     }
   end
 
+  def test_readbyte
+    start_server { |port|
+      server_connect(port) { |ssl|
+        str = +("x" * 100 + "\n")
+        ssl.syswrite(str)
+        newstr = str.bytesize.times.map { |i|
+          ssl.readbyte
+        }.pack("C*")
+        assert_equal(str, newstr)
+      }
+    }
+  end
+
   def test_sync_close
     start_server do |port|
       begin

test/openssl/ut_eof.rb

@@ -8,6 +8,10 @@ module OpenSSL::TestEOF
     open_file("") {|f| assert_nil f.getbyte }
   end
 
+  def test_readbyte_eof
+    open_file("") {|f| assert_raise(EOFError) { f.readbyte } }
+  end
+
   def test_eof_0
     open_file("") {|f|
       assert_equal("", f.read(0))