go/system: adding two-phase data pipe methods

mojo/go/tests/system_test.go

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package tests
 
 import (
         "bytes"
         "testing"
 
@@ skipping 172 matching lines @@
         }
         if !hp.IsValid() || !hc.IsValid() {
                 t.Fatalf("CreateDataPipe returned invalid handles hp:%v hc:%v", hp, hc)
         }
         if r, _ = hc.Wait(system.MOJO_HANDLE_SIGNAL_READABLE, 0); r != system.MOJO_RESULT_DEADLINE_EXCEEDED {
                 t.Fatalf("hc should not be readable:%v", r)
         }
         if r, _ = hp.Wait(system.MOJO_HANDLE_SIGNAL_WRITABLE, 0); r != system.MOJO_RESULT_OK {
                 t.Fatalf("hp should be writeable:%v", r)
         }
+
+        // Test one-phase read/write.
+        // Writing.
         kHello := []byte("hello")
         r, numBytes := hp.WriteData(kHello, system.MOJO_WRITE_DATA_FLAG_NONE)
         if r != system.MOJO_RESULT_OK || numBytes != len(kHello) {
                 t.Fatalf("Failed WriteData on hp:%v numBytes:%d", r, numBytes)
         }
+        // Reading.
         if r, _ = hc.Wait(system.MOJO_HANDLE_SIGNAL_READABLE, 1000); r != system.MOJO_RESULT_OK {
                 t.Fatalf("hc should be readable after WriteData on hp:%v", r)
         }
         r, data := hc.ReadData(system.MOJO_READ_DATA_FLAG_NONE)
         if r != system.MOJO_RESULT_OK {
                 t.Fatalf("Failed ReadData on hc:%v", r)
         }
         if !bytes.Equal(data, kHello) {
                 t.Fatalf("Invalid data expected:%s, got:%s", kHello, data)
         }
+
+        // Test two-phase read/write.
+        // Writing.
+        kHello = []byte("Hello, world!")
+        r, buf := hp.BeginWriteData(len(kHello), system.MOJO_WRITE_DATA_FLAG_ALL_OR_NONE)
+        if r != system.MOJO_RESULT_OK {
+                t.Fatalf("Failed BeginWriteData on hp:%v numBytes:%d", r, len(kHello))
+        }
+        if len(buf) < len(kHello) {
+                t.Fatalf("Buffer size(%d) should be at least %d", len(buf), len(kHello))
+        }
+        copy(buf, kHello)
+        if r, _ := hp.WriteData(kHello, system.MOJO_WRITE_DATA_FLAG_NONE); r != system.MOJO_RESULT_BUSY {
+                t.Fatalf("hp should be busy during a two-phase write: %v", r)
+        }
+        if r, _ = hc.Wait(system.MOJO_HANDLE_SIGNAL_READABLE, 10); r != system.MOJO_RESULT_DEADLINE_EXCEEDED {
+                t.Fatalf("hc shouldn't be readable before EndWriteData on hp:%v", r)
+        }
+        if r := hp.EndWriteData(len(kHello)); r != system.MOJO_RESULT_OK {
+                t.Fatalf("Failed EndWriteData on hp:%v", r)
+        }
+        // Reading.
+        if r, _ = hc.Wait(system.MOJO_HANDLE_SIGNAL_READABLE, 1000); r != system.MOJO_RESULT_OK {

[jamesr, 2015/01/21 18:56:15]

sorry I missed this earlier, but what does the constant "1000" signify here?  If
this is the deadline then we should probably pass MOJO_DEADLINE_INDEFINITE to
avoid flaky behavior when the system is unexpected slow or preempted at
unfortunate times. alternately if we never want to wait we should pass 0 here

[rogulenko, 2015/01/21 19:59:59]

Changed all deadlines to either MOJO_DEADLINE_INDEFINITE or 0.

+                t.Fatalf("hc should be readable after EndWriteData on hp:%v", r)
+        }
+        if r, buf = hc.BeginReadData(len(kHello), system.MOJO_READ_DATA_FLAG_ALL_OR_NONE); r != system.MOJO_RESULT_OK {
+                t.Fatalf("Failed BeginReadData on hc:%v numBytes:%d", r, len(kHello))
+        }
+        if len(buf) != len(kHello) {
+                t.Fatalf("Buffer size(%d) should be equal to %d", len(buf), len(kHello))
+        }
+        if r, _ := hc.ReadData(system.MOJO_READ_DATA_FLAG_NONE); r != system.MOJO_RESULT_BUSY {
+                t.Fatalf("hc should be busy during a two-phase read: %v", r)
+        }
+        if !bytes.Equal(buf, kHello) {
+                t.Fatalf("Invalid data expected:%s, got:%s", kHello, buf)
+        }
+        if r := hc.EndReadData(len(buf)); r != system.MOJO_RESULT_OK {
+                t.Fatalf("Failed EndReadData on hc:%v", r)
+        }
+
         if r = hp.Close(); r != system.MOJO_RESULT_OK {
                 t.Fatalf("Close on hp failed:%v", r)
         }
         if r, _ = hc.Wait(system.MOJO_HANDLE_SIGNAL_READABLE, 100); r != system.MOJO_RESULT_FAILED_PRECONDITION {
                 t.Fatalf("hc should not be readable after hp closed:%v", r)
         }
         if r = hc.Close(); r != system.MOJO_RESULT_OK {
                 t.Fatalf("Close on hc failed:%v", r)
         }
 }
@@ skipping 38 matching lines @@
         if buf[0] != 'x' || buf[1] != 'y' {
                 t.Fatalf("Failed to validate shared buffer. expected:x,y got:%s,%s", buf[0], buf[1])
         }
         if r = h1.UnmapBuffer(buf); r != system.MOJO_RESULT_OK {
                 t.Fatalf("UnmapBuffer failed:%v", r)
         }
         if r = h1.Close(); r != system.MOJO_RESULT_OK {
                 t.Fatalf("Close on h1 failed:%v", r)
         }
 }