output_buffering handles odd EAGAIN cases

The tiny responses for check_client_connection and "100-Continue"
responses may occasionally fail with EAGAIN.  We must be prepared
for those corner cases and buffer the output appropriately.  We can
safely use a string for buffering here (for once(!)), since the
buffer sizes are bounded and known at buffer time, unlike the
response headers/bodies sent by the Rack application.

1 files changed, 58 insertions, 14 deletions

diff --git a/lib/yahns/http_response.rb b/lib/yahns/http_response.rb
index a34832a..df935e9 100644
--- a/lib/yahns/http_response.rb
+++ b/lib/yahns/http_response.rb
@@ -2,6 +2,7 @@
 # Copyright (C) 2013, Eric Wong <normalperson@yhbt.net> and all contributors
 # License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
 require_relative 'stream_file'
+require_relative 'wbuf_str'
 
 # Writes a Rack response to your client using the HTTP/1.1 specification.
 # You use it by simply doing:
@@ -18,7 +19,8 @@ module Yahns::HttpResponse # :nodoc:
   CONN_KA = "Connection: keep-alive\r\n\r\n"
   CONN_CLOSE = "Connection: close\r\n\r\n"
   Z = ""
-  RESPONSE_START = "HTTP/1.1 "
+  CCC_RESPONSE_START = [ 'HTTP', '/1.1 ' ].map!(&:freeze)
+  RESPONSE_START = CCC_RESPONSE_START.join('')
   R100_RAW = "HTTP/1.1 100 Continue\r\n\r\n"
   R100_CCC = "100 Continue\r\n\r\nHTTP/1.1 "
   HTTP_EXPECT = "HTTP_EXPECT"
@@ -27,22 +29,13 @@ module Yahns::HttpResponse # :nodoc:
     @response_start_sent ? Z : RESPONSE_START
   end
 
-  # only used if input_buffering is true (not :lazy or false)
-  # :lazy/false gives control to the app
-  def http_100_response(env)
-    if env[HTTP_EXPECT] =~ /\A100-continue\z/i
-      kgio_write(@response_start_sent ? R100_CCC : R100_RAW)
-      env.delete(HTTP_EXPECT)
-    end
-  end
-
   def response_wait_write(rv)
     # call the kgio_wait_readable or kgio_wait_writable method
     ok = __send__("kgio_#{rv}") and return ok
     k = self.class
     k.logger.info("fd=#{fileno} ip=#@kgio_addr timeout on :#{rv} after "\
                   "#{k.client_timeout}s")
-    nil
+    false
   end
 
   def err_response(code)
@@ -93,7 +86,7 @@ module Yahns::HttpResponse # :nodoc:
       # shutdown is needed in case the app forked, we rescue here since
       # StreamInput may issue shutdown as well
       shutdown rescue nil
-      nil # trigger close
+      :close
     end
   end
 
@@ -145,7 +138,7 @@ module Yahns::HttpResponse # :nodoc:
           body = nil # ensure we do not close body in ensure
           return rv
         else
-          response_wait_write(rv) or return
+          response_wait_write(rv) or return :close
         end
       end while true
     end
@@ -176,7 +169,7 @@ module Yahns::HttpResponse # :nodoc:
             rv = wbuf.wbuf_write(self, chunk)
             break
           else
-            response_wait_write(rv) or return
+            response_wait_write(rv) or return :close
           end
         end while true
       end
@@ -193,4 +186,55 @@ module Yahns::HttpResponse # :nodoc:
   ensure
     body.respond_to?(:close) and body.close
   end
+
+  # returns nil on success
+  # :wait_readable/:wait_writable/:close for epoll
+  def do_ccc
+    @response_start_sent = true
+    wbuf = nil
+    rv = nil
+    CCC_RESPONSE_START.each do |buf|
+      if wbuf
+        wbuf << buf
+      else
+        case rv = kgio_trywrite(buf)
+        when nil
+          break
+        when String
+          buf = rv
+        when :wait_writable, :wait_readable
+          if self.class.output_buffering
+            wbuf = buf.dup
+            @state = Yahns::WbufStr.new(wbuf, :ccc_done)
+            break
+          else
+            response_wait_write(rv) or return :close
+          end
+        end while true
+      end
+    end
+    rv
+  end
+
+  # only used if input_buffering is true (not :lazy or false)
+  # input_buffering==:lazy/false gives control to the app
+  # returns nil on success
+  # returns :close, :wait_writable, or :wait_readable
+  def http_100_response(env)
+    env.delete(HTTP_EXPECT) =~ /\A100-continue\z/i or return nil
+    buf = @response_start_sent ? R100_CCC : R100_RAW
+    case rv = kgio_trywrite(buf)
+    when String
+      buf = rv
+    when :wait_writable, :wait_readable
+      if self.class.output_buffering
+        @state = Yahns::WbufStr.new(buf, :r100_done)
+        return rv
+      else
+        response_wait_write(rv) or return :close
+      end
+    else
+      return rv
+    end while true
+  end
 end