[NaCl SDK] nacl_io: Add test for write/read fix.

I've also changed the MountFactory used by the KernelProxy into an object
instead of a function. This makes it easier to replace in tests.

I've also added MountMock and MountNodeMock which are gmock wrappers for Mount
and MountNode, respectively.

BUG=254675
R=noelallen@chromium.org

Review URL: https://codereview.chromium.org/17955003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@209510 0039d316-1c4b-4281-b951-d872f2087c98

23 files changed, 361 insertions, 104 deletions

diff --git a/native_client_sdk/src/build_tools/sdk_files.list b/native_client_sdk/src/build_tools/sdk_files.list
index fd6fc1f..ffc959a 100644
--- a/native_client_sdk/src/build_tools/sdk_files.list
+++ b/native_client_sdk/src/build_tools/sdk_files.list
@@ -265,6 +265,7 @@ include/nacl_io/kernel_wrap.h
 include/nacl_io/kernel_wrap_real.h
 include/nacl_io/mount_dev.h
 include/nacl_io/mount.h
+include/nacl_io/mount_factory.h
 include/nacl_io/mount_html5fs.h
 include/nacl_io/mount_http.h
 include/nacl_io/mount_mem.h
@@ -288,6 +289,7 @@ include/nacl_io/pepper/define_empty_macros.h
 include/nacl_io/pepper_interface.h
 include/nacl_io/pepper/undef_macros.h
 include/nacl_io/real_pepper_interface.h
+include/nacl_io/typed_mount_factory.h
 include/ppapi/c/dev/deprecated_bool.h
 include/ppapi/c/dev/ppb_audio_input_dev.h
 include/ppapi/c/dev/ppb_buffer_dev.h
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
index bc62c37..8d5655a 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
@@ -25,6 +25,7 @@
 #include "nacl_io/osstat.h"
 #include "nacl_io/path.h"
 #include "nacl_io/pepper_interface.h"
+#include "nacl_io/typed_mount_factory.h"
 #include "sdk_util/auto_lock.h"
 #include "sdk_util/ref_object.h"
 
@@ -38,18 +39,27 @@
 
 KernelProxy::KernelProxy() : dev_(0), ppapi_(NULL) {}
 
-KernelProxy::~KernelProxy() { delete ppapi_; }
+KernelProxy::~KernelProxy() {
+  // Clean up the MountFactories.
+  for (MountFactoryMap_t::iterator i = factories_.begin();
+       i != factories_.end();
+       ++i) {
+    delete i->second;
+  }
+
+  delete ppapi_;
+}
 
 void KernelProxy::Init(PepperInterface* ppapi) {
   ppapi_ = ppapi;
   cwd_ = "/";
   dev_ = 1;
 
-  factories_["memfs"] = MountMem::Create<MountMem>;
-  factories_["dev"] = MountDev::Create<MountDev>;
-  factories_["html5fs"] = MountHtml5Fs::Create<MountHtml5Fs>;
-  factories_["httpfs"] = MountHttp::Create<MountHttp>;
-  factories_["passthroughfs"] = MountPassthrough::Create<MountPassthrough>;
+  factories_["memfs"] = new TypedMountFactory<MountMem>;
+  factories_["dev"] = new TypedMountFactory<MountDev>;
+  factories_["html5fs"] = new TypedMountFactory<MountHtml5Fs>;
+  factories_["httpfs"] = new TypedMountFactory<MountHttp>;
+  factories_["passthroughfs"] = new TypedMountFactory<MountPassthrough>;
 
   int result;
   result = mount("", "/", "passthroughfs", 0, NULL);
@@ -91,7 +101,6 @@ int KernelProxy::open(const char* path, int oflags) {
   return AllocateFD(handle);
 }
 
-
 int KernelProxy::close(int fd) {
   ScopedKernelHandle handle;
   Error error = AcquireHandle(fd, &handle);
@@ -302,7 +311,8 @@ int KernelProxy::mount(const char* source,
     free(str);
   }
 
-  Error error = factory->second(dev_++, smap, ppapi_, &mounts_[abs_targ]);
+  Error error =
+      factory->second->CreateMount(dev_++, smap, ppapi_, &mounts_[abs_targ]);
   if (error) {
     errno = error;
     return -1;
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
index ac3b936..554a75ca 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
@@ -5,22 +5,14 @@
 #ifndef LIBRARIES_NACL_IO_KERNEL_PROXY_H_
 #define LIBRARIES_NACL_IO_KERNEL_PROXY_H_
 
-#include <ppapi/c/pp_instance.h>
-#include <ppapi/c/ppb.h>
-#include <pthread.h>
 #include <map>
 #include <string>
-#include <vector>
 
 #include "nacl_io/kernel_object.h"
-#include "nacl_io/mount.h"
+#include "nacl_io/mount_factory.h"
 #include "nacl_io/ostypes.h"
 #include "nacl_io/osutime.h"
-#include "nacl_io/path.h"
 
-class KernelHandle;
-class Mount;
-class MountNode;
 class PepperInterface;
 
 // KernelProxy provide one-to-one mapping for libc kernel calls.  Calls to the
@@ -30,12 +22,7 @@ class PepperInterface;
 // other classes should return Error (as defined by nacl_io/error.h).
 class KernelProxy : protected KernelObject {
  public:
-  typedef Error (*MountFactory_t)(int,
-                                  StringMap_t&,
-                                  PepperInterface*,
-                                  ScopedMount*);
-  typedef std::map<std::string, std::string> StringMap_t;
-  typedef std::map<std::string, MountFactory_t> MountFactoryMap_t;
+  typedef std::map<std::string, MountFactory*> MountFactoryMap_t;
 
   KernelProxy();
   virtual ~KernelProxy();
diff --git a/native_client_sdk/src/libraries/nacl_io/library.dsc b/native_client_sdk/src/libraries/nacl_io/library.dsc
index c582991..eef0ac6 100644
--- a/native_client_sdk/src/libraries/nacl_io/library.dsc
+++ b/native_client_sdk/src/libraries/nacl_io/library.dsc
@@ -48,6 +48,7 @@
         "kernel_wrap_real.h",
         "mount.h",
         "mount_dev.h",
+        "mount_factory.h",
         "mount_html5fs.h",
         "mount_http.h",
         "mount_mem.h",
@@ -68,6 +69,7 @@
         "path.h",
         "pepper_interface.h",
         "real_pepper_interface.h",
+        "typed_mount_factory.h",
       ],
       'DEST': 'include/nacl_io',
     },
diff --git a/native_client_sdk/src/libraries/nacl_io/mount.h b/native_client_sdk/src/libraries/nacl_io/mount.h
index 89f9b88..58cf1a4 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount.h
@@ -24,7 +24,6 @@ class PepperInterface;
 typedef ScopedRef<Mount> ScopedMount;
 typedef std::map<std::string, std::string> StringMap_t;
 
-
 // NOTE: The KernelProxy is the only class that should be setting errno. All
 // other classes should return Error (as defined by nacl_io/error.h).
 class Mount : public RefObject {
@@ -41,13 +40,6 @@ class Mount : public RefObject {
   virtual void Destroy();
 
  public:
-  template <class M>
-  // Assumes that |out_mount| is non-NULL.
-  static Error Create(int dev,
-                      StringMap_t& args,
-                      PepperInterface* ppapi,
-                      ScopedMount* out_mount);
-
   PepperInterface* ppapi() { return ppapi_; }
 
   // All paths in functions below are expected to containing a leading "/".
@@ -98,20 +90,4 @@ class Mount : public RefObject {
   DISALLOW_COPY_AND_ASSIGN(Mount);
 };
 
-/*static*/
-template <class M>
-Error Mount::Create(int dev,
-                    StringMap_t& args,
-                    PepperInterface* ppapi,
-                    ScopedMount* out_mount) {
-  ScopedMount mnt(new M());
-  Error error = mnt->Init(dev, args, ppapi);
-  if (error)
-    return error;
-
-  *out_mount = mnt;
-  return 0;
-}
-
-
 #endif  // LIBRARIES_NACL_IO_MOUNT_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_dev.h b/native_client_sdk/src/libraries/nacl_io/mount_dev.h
index 2d57102..5d47838 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_dev.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_dev.h
@@ -6,6 +6,7 @@
 #define LIBRARIES_NACL_IO_MOUNT_DEV_H_
 
 #include "nacl_io/mount.h"
+#include "nacl_io/typed_mount_factory.h"
 
 class MountNode;
 
@@ -26,7 +27,8 @@ class MountDev : public Mount {
  private:
   ScopedMountNode root_;
 
-  friend class Mount;
+  friend class TypedMountFactory<MountDev>;
+  DISALLOW_COPY_AND_ASSIGN(MountDev);
 };
 
 #endif  // LIBRARIES_NACL_IO_MOUNT_DEV_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_factory.h b/native_client_sdk/src/libraries/nacl_io/mount_factory.h
new file mode 100644
index 0000000..35f77d7
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/mount_factory.h
@@ -0,0 +1,29 @@
+/* Copyright (c) 2013 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.
+ */
+#ifndef LIBRARIES_NACL_IO_MOUNT_FACTORY_H_
+#define LIBRARIES_NACL_IO_MOUNT_FACTORY_H_
+
+#include <map>
+#include <string>
+
+#include "nacl_io/error.h"
+#include "sdk_util/scoped_ref.h"
+
+class PepperInterface;
+class Mount;
+
+typedef std::map<std::string, std::string> StringMap_t;
+
+class MountFactory {
+ public:
+  virtual ~MountFactory() {}
+  virtual Error CreateMount(int dev,
+                            StringMap_t& args,
+                            PepperInterface* ppapi,
+                            ScopedRef<Mount>* out_mount) = 0;
+};
+
+#endif  // LIBRARIES_NACL_IO_MOUNT_FACTORY_H_
+
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
index ff25e53..d2e1b08 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
@@ -6,8 +6,10 @@
 #define LIBRARIES_NACL_IO_MOUNT_HTML5FS_H_
 
 #include <pthread.h>
+
 #include "nacl_io/mount.h"
 #include "nacl_io/pepper_interface.h"
+#include "nacl_io/typed_mount_factory.h"
 
 class MountNode;
 
@@ -39,7 +41,7 @@ class MountHtml5Fs : public Mount {
   Error filesystem_open_error_;      // protected by lock_.
   pthread_cond_t filesystem_open_cond_;
 
-  friend class Mount;
+  friend class TypedMountFactory<MountHtml5Fs>;
 };
 
 #endif  // LIBRARIES_NACL_IO_MOUNT_HTML5FS_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_http.h b/native_client_sdk/src/libraries/nacl_io/mount_http.h
index cf3feb9..e804f37 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_http.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_http.h
@@ -9,10 +9,9 @@
 #include <string>
 #include "nacl_io/mount.h"
 #include "nacl_io/pepper_interface.h"
+#include "nacl_io/typed_mount_factory.h"
 
 class MountNode;
-class MountNodeDir;
-class MountNodeHttp;
 class MountHttpMock;
 
 std::string NormalizeHeaderKey(const std::string& s);
@@ -54,7 +53,7 @@ class MountHttp : public Mount {
   bool cache_stat_;
   bool cache_content_;
 
-  friend class Mount;
+  friend class TypedMountFactory<MountHttp>;
   friend class MountNodeHttp;
   friend class MountHttpMock;
 };
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_mem.h b/native_client_sdk/src/libraries/nacl_io/mount_mem.h
index 523ca4f..9bd679d 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_mem.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_mem.h
@@ -5,10 +5,8 @@
 #ifndef LIBRARIES_NACL_IO_MOUNT_MEM_H_
 #define LIBRARIES_NACL_IO_MOUNT_MEM_H_
 
-#include <map>
-#include <string>
-
 #include "nacl_io/mount.h"
+#include "nacl_io/typed_mount_factory.h"
 
 class MountMem : public Mount {
  protected:
@@ -44,7 +42,7 @@ private:
 
   ScopedMountNode root_;
 
-  friend class Mount;
+  friend class TypedMountFactory<MountMem>;
   DISALLOW_COPY_AND_ASSIGN(MountMem);
 };
 
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node.cc b/native_client_sdk/src/libraries/nacl_io/mount_node.cc
index ec77b97..424df70 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
-x * Use of this source code is governed by a BSD-style license that can be
+ * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "nacl_io/mount_node.h"
@@ -48,9 +48,7 @@ void MountNode::Destroy() {
 
 Error MountNode::FSync() { return 0; }
 
-Error MountNode::FTruncate(off_t length) {
-  return EINVAL;
-}
+Error MountNode::FTruncate(off_t length) { return EINVAL; }
 
 Error MountNode::GetDents(size_t offs,
                           struct dirent* pdir,
@@ -66,9 +64,7 @@ Error MountNode::GetStat(struct stat* pstat) {
   return 0;
 }
 
-Error MountNode::Ioctl(int request, char* arg) {
-  return EINVAL;
-}
+Error MountNode::Ioctl(int request, char* arg) { return EINVAL; }
 
 Error MountNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
   *out_bytes = 0;
@@ -140,25 +136,16 @@ Error MountNode::AddChild(const std::string& name,
   return ENOTDIR;
 }
 
-Error MountNode::RemoveChild(const std::string& name) {
-  return ENOTDIR;
-}
+Error MountNode::RemoveChild(const std::string& name) { return ENOTDIR; }
 
-Error MountNode::FindChild(const std::string& name,
-                           ScopedMountNode* out_node) {
+Error MountNode::FindChild(const std::string& name, ScopedMountNode* out_node) {
   out_node->reset(NULL);
   return ENOTDIR;
 }
 
-int MountNode::ChildCount() {
-  return 0;
-}
+int MountNode::ChildCount() { return 0; }
 
-void MountNode::Link() {
-  stat_.st_nlink++;
-}
+void MountNode::Link() { stat_.st_nlink++; }
 
-void MountNode::Unlink() {
-  stat_.st_nlink--;
-}
+void MountNode::Unlink() { stat_.st_nlink--; }
 
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node.h b/native_client_sdk/src/libraries/nacl_io/mount_node.h
index f790b33..fb0f14f 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node.h
@@ -21,7 +21,6 @@ class MountNode;
 
 typedef ScopedRef<MountNode> ScopedMountNode;
 
-
 // NOTE: The KernelProxy is the only class that should be setting errno. All
 // other classes should return Error (as defined by nacl_io/error.h).
 class MountNode : public RefObject {
@@ -70,7 +69,7 @@ class MountNode : public RefObject {
   virtual int GetMode();
   virtual int GetType();
   // Assume that |out_size| is non-NULL.
-  virtual Error GetSize(size_t *out_size);
+  virtual Error GetSize(size_t* out_size);
   virtual bool IsaDir();
   virtual bool IsaFile();
   virtual bool IsaTTY();
@@ -99,7 +98,7 @@ class MountNode : public RefObject {
   struct stat stat_;
 
   // We use a pointer directly to avoid cycles in the ref count.
-  // TODO(noelallen) We should change this to it's unnecessary for the node
+  // TODO(noelallen) We should change this so it's unnecessary for the node
   // to track it's parent.  When a node is unlinked, the mount should do
   // any cleanup it needs.
   Mount* mount_;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
index 7b59b05..4d441a0 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
@@ -6,6 +6,7 @@
 #define LIBRARIES_NACL_IO_MOUNT_PASSTHROUGH_H_
 
 #include "nacl_io/mount.h"
+#include "nacl_io/typed_mount_factory.h"
 
 class MountPassthrough : public Mount {
  protected:
@@ -24,8 +25,8 @@ class MountPassthrough : public Mount {
   virtual Error Remove(const Path& path);
 
 private:
-  friend class Mount;
-  DISALLOW_COPY_AND_ASSIGN(MountPassthrough);
+ friend class TypedMountFactory<MountPassthrough>;
+ DISALLOW_COPY_AND_ASSIGN(MountPassthrough);
 };
 
 #endif  // LIBRARIES_NACL_IO_MOUNT_PASSTHROUGH_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/typed_mount_factory.h b/native_client_sdk/src/libraries/nacl_io/typed_mount_factory.h
new file mode 100644
index 0000000..c859b0b
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/typed_mount_factory.h
@@ -0,0 +1,29 @@
+/* Copyright (c) 2013 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.
+ */
+#ifndef LIBRARIES_NACL_IO_TYPED_MOUNT_FACTORY_H_
+#define LIBRARIES_NACL_IO_TYPED_MOUNT_FACTORY_H_
+
+#include "nacl_io/mount.h"
+#include "nacl_io/mount_factory.h"
+
+template <typename T>
+class TypedMountFactory : public MountFactory {
+ public:
+  virtual Error CreateMount(int dev,
+                            StringMap_t& args,
+                            PepperInterface* ppapi,
+                            ScopedRef<Mount>* out_mount) {
+    ScopedRef<T> mnt(new T());
+    Error error = mnt->Init(dev, args, ppapi);
+    if (error)
+      return error;
+
+    *out_mount = mnt;
+    return 0;
+  }
+};
+
+#endif  // LIBRARIES_NACL_IO_TYPED_MOUNT_FACTORY_H_
+
diff --git a/native_client_sdk/src/libraries/nacl_io_test/example.dsc b/native_client_sdk/src/libraries/nacl_io_test/example.dsc
index 63b0ef4..b26cd7c 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/example.dsc
+++ b/native_client_sdk/src/libraries/nacl_io_test/example.dsc
@@ -15,9 +15,13 @@
         'kernel_wrap_test.cc',
         'main.cc',
         'mock_util.h',
-        'mount_node_test.cc',
         'mount_html5fs_test.cc',
         'mount_http_test.cc',
+        'mount_mock.cc',
+        'mount_mock.h',
+        'mount_node_mock.cc',
+        'mount_node_mock.h',
+        'mount_node_test.cc',
         'mount_test.cc',
         'path_test.cc',
         'pepper_interface_mock.cc',
diff --git a/native_client_sdk/src/libraries/nacl_io_test/example.js b/native_client_sdk/src/libraries/nacl_io_test/example.js
index 3b4de45..bd17594 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/example.js
+++ b/native_client_sdk/src/libraries/nacl_io_test/example.js
@@ -60,7 +60,7 @@ function handleMessage(event) {
   // in the test failure summary).
   var argList = msg.substr(firstColon + 1);
   args = [];
-  for (var i = 0; i < argCount; ++i) {
+  for (var i = 0; i < argCount - 1; ++i) {
     var arg;
     var comma = argList.indexOf(',');
     if (comma === -1) {
@@ -78,5 +78,8 @@ function handleMessage(event) {
     args.push(arg);
   }
 
+  // Last argument is the rest of the message.
+  args.push(argList);
+
   cmdFunction.apply(null, args);
 }
diff --git a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_mock.cc b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_mock.cc
index 279a8ea..367569e 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_mock.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_mock.cc
@@ -6,8 +6,7 @@
 #include "kernel_proxy_mock.h"
 #include "nacl_io/kernel_intercept.h"
 
-KernelProxyMock::KernelProxyMock() {
-}
+KernelProxyMock::KernelProxyMock() {}
 
 KernelProxyMock::~KernelProxyMock() {
   // Uninitialize the kernel proxy so wrapped functions passthrough to their
diff --git a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
index 601f3b7..70e76e1 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
@@ -11,15 +11,30 @@
 #include <map>
 #include <string>
 
-#include "nacl_io/kernel_handle.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#include "mount_mock.h"
+#include "mount_node_mock.h"
+
 #include "nacl_io/kernel_intercept.h"
 #include "nacl_io/kernel_proxy.h"
 #include "nacl_io/mount.h"
 #include "nacl_io/mount_mem.h"
 #include "nacl_io/osmman.h"
 #include "nacl_io/path.h"
+#include "nacl_io/typed_mount_factory.h"
 
-#include "gtest/gtest.h"
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::Invoke;
+using ::testing::Return;
+using ::testing::SaveArg;
+using ::testing::SetArgPointee;
+using ::testing::StrEq;
+using ::testing::WithArgs;
+
+namespace {
 
 class KernelProxyFriend : public KernelProxy {
  public:
@@ -44,22 +59,24 @@ class KernelProxyTest : public ::testing::Test {
   KernelProxyFriend* kp_;
 };
 
+}  // namespace
+
 TEST_F(KernelProxyTest, FileLeak) {
   const size_t buffer_size = 1024;
   char filename[128];
   int file_num;
   int garbage[buffer_size];
 
-  MountMem* mount = (MountMem*) kp_->RootMount();
+  MountMem* mount = (MountMem*)kp_->RootMount();
   ScopedMountNode root;
 
   EXPECT_EQ(0, mount->Open(Path("/"), O_RDONLY, &root));
   EXPECT_EQ(0, root->ChildCount());
 
-  for (file_num=0; file_num < 4096; file_num++) {
+  for (file_num = 0; file_num < 4096; file_num++) {
     sprintf(filename, "/foo%i.tmp", file_num++);
-    FILE *f = fopen(filename, "w");
-    EXPECT_NE((FILE *) 0, f);
+    FILE* f = fopen(filename, "w");
+    EXPECT_NE((FILE*)0, f);
     EXPECT_EQ(1, root->ChildCount());
     EXPECT_EQ(buffer_size, fwrite(garbage, 1, buffer_size, f));
     fclose(f);
@@ -227,6 +244,8 @@ TEST_F(KernelProxyTest, MemMountDup) {
   // fd, new_fd, dup_fd -> "/bar"
 }
 
+namespace {
+
 StringMap_t g_StringMap;
 
 class MountMockInit : public MountMem {
@@ -237,13 +256,14 @@ class MountMockInit : public MountMem {
       return EINVAL;
     return 0;
   }
-  ;
+
+  friend class TypedMountFactory<MountMockInit>;
 };
 
 class KernelProxyMountMock : public KernelProxy {
   virtual void Init(PepperInterface* ppapi) {
     KernelProxy::Init(NULL);
-    factories_["initfs"] = MountMockInit::Create<MountMockInit>;
+    factories_["initfs"] = new TypedMountFactory<MountMockInit>;
   }
 };
 
@@ -260,6 +280,8 @@ class KernelProxyMountTest : public ::testing::Test {
   KernelProxy* kp_;
 };
 
+}  // namespace
+
 TEST_F(KernelProxyMountTest, MountInit) {
   int res1 = ki_mount("/", "/mnt1", "initfs", 0, "false,foo=bar");
 
@@ -326,12 +348,14 @@ class MountMockMMap : public Mount {
   virtual Error Mkdir(const Path& path, int permissions) { return ENOSYS; }
   virtual Error Rmdir(const Path& path) { return ENOSYS; }
   virtual Error Remove(const Path& path) { return ENOSYS; }
+
+  friend class TypedMountFactory<MountMockMMap>;
 };
 
 class KernelProxyMockMMap : public KernelProxy {
   virtual void Init(PepperInterface* ppapi) {
     KernelProxy::Init(NULL);
-    factories_["mmapfs"] = MountMockInit::Create<MountMockMMap>;
+    factories_["mmapfs"] = new TypedMountFactory<MountMockMMap>;
   }
 };
 
@@ -376,3 +400,103 @@ TEST_F(KernelProxyMMapTest, MMap) {
   EXPECT_EQ(3, g_MMapCount);
 }
 
+namespace {
+
+class SingletonMountFactory : public MountFactory {
+ public:
+  SingletonMountFactory(const ScopedMount& mount) : mount_(mount) {}
+
+  virtual Error CreateMount(int dev,
+                            StringMap_t& args,
+                            PepperInterface* ppapi,
+                            ScopedMount* out_mount) {
+    *out_mount = mount_;
+    return 0;
+  }
+
+ private:
+  ScopedMount mount_;
+};
+
+class KernelProxyError : public KernelProxy {
+ public:
+  KernelProxyError() : mnt_(new MountMock) {}
+
+  virtual void Init(PepperInterface* ppapi) {
+    KernelProxy::Init(ppapi);
+    factories_["testfs"] = new SingletonMountFactory(mnt_);
+
+    EXPECT_CALL(*mnt_, Destroy()).Times(1);
+  }
+
+  ScopedRef<MountMock> mnt() { return mnt_; }
+
+ private:
+  ScopedRef<MountMock> mnt_;
+};
+
+class KernelProxyErrorTest : public ::testing::Test {
+ public:
+  KernelProxyErrorTest() : kp_(new KernelProxyError) {
+    ki_init(kp_);
+    // Unmount the passthrough FS and mount a testfs.
+    EXPECT_EQ(0, kp_->umount("/"));
+    EXPECT_EQ(0, kp_->mount("", "/", "testfs", 0, NULL));
+  }
+
+  ~KernelProxyErrorTest() {
+    ki_uninit();
+    delete kp_;
+  }
+
+  ScopedRef<MountMock> mnt() { return kp_->mnt(); }
+
+ private:
+  KernelProxyError* kp_;
+};
+
+}  // namespace
+
+TEST_F(KernelProxyErrorTest, WriteError) {
+  ScopedRef<MountMock> mock_mnt(mnt());
+  ScopedRef<MountNodeMock> mock_node(new MountNodeMock(&*mock_mnt));
+  EXPECT_CALL(*mock_mnt, Open(_, _, _))
+      .WillOnce(DoAll(SetArgPointee<2>(mock_node), Return(0)));
+
+  EXPECT_CALL(*mock_node, Write(_, _, _, _))
+      .WillOnce(DoAll(SetArgPointee<3>(0),  // Wrote 0 bytes.
+                      Return(1234)));       // Returned error 1234.
+
+  EXPECT_CALL(*mock_node, Destroy()).Times(1);
+
+  int fd = ki_open("/dummy", O_WRONLY);
+  EXPECT_NE(0, fd);
+
+  char buf[20];
+  EXPECT_EQ(-1, ki_write(fd, &buf[0], 20));
+  // The Mount should be able to return whatever error it wants and have it
+  // propagate through.
+  EXPECT_EQ(1234, errno);
+}
+
+TEST_F(KernelProxyErrorTest, ReadError) {
+  ScopedRef<MountMock> mock_mnt(mnt());
+  ScopedRef<MountNodeMock> mock_node(new MountNodeMock(&*mock_mnt));
+  EXPECT_CALL(*mock_mnt, Open(_, _, _))
+      .WillOnce(DoAll(SetArgPointee<2>(mock_node), Return(0)));
+
+  EXPECT_CALL(*mock_node, Read(_, _, _, _))
+      .WillOnce(DoAll(SetArgPointee<3>(0),  // Read 0 bytes.
+                      Return(1234)));       // Returned error 1234.
+
+  EXPECT_CALL(*mock_node, Destroy()).Times(1);
+
+  int fd = ki_open("/dummy", O_RDONLY);
+  EXPECT_NE(0, fd);
+
+  char buf[20];
+  EXPECT_EQ(-1, ki_read(fd, &buf[0], 20));
+  // The Mount should be able to return whatever error it wants and have it
+  // propagate through.
+  EXPECT_EQ(1234, errno);
+}
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_mock.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_mock.cc
new file mode 100644
index 0000000..4b69108
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_mock.cc
@@ -0,0 +1,11 @@
+/* Copyright (c) 2013 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.
+ */
+
+#include "mount_mock.h"
+
+MountMock::MountMock() {}
+
+MountMock::~MountMock() {}
+
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_mock.h b/native_client_sdk/src/libraries/nacl_io_test/mount_mock.h
new file mode 100644
index 0000000..7ceebc4
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_mock.h
@@ -0,0 +1,30 @@
+/* Copyright (c) 2013 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.
+ */
+
+#ifndef LIBRARIES_NACL_IO_TEST_MOUNT_MOCK_H_
+#define LIBRARIES_NACL_IO_TEST_MOUNT_MOCK_H_
+
+#include "gmock/gmock.h"
+
+#include "nacl_io/mount.h"
+
+class MountMock : public Mount {
+ public:
+  MountMock();
+  virtual ~MountMock();
+
+  MOCK_METHOD3(Init, Error(int, StringMap_t&, PepperInterface*));
+  MOCK_METHOD0(Destroy, void());
+  MOCK_METHOD2(Access, Error(const Path&, int));
+  MOCK_METHOD3(Open, Error(const Path&, int, ScopedMountNode*));
+  MOCK_METHOD2(OpenResource, Error(const Path&, ScopedMountNode*));
+  MOCK_METHOD1(Unlink, Error(const Path&));
+  MOCK_METHOD2(Mkdir, Error(const Path&, int));
+  MOCK_METHOD1(Rmdir, Error(const Path&));
+  MOCK_METHOD1(Remove, Error(const Path&));
+};
+
+#endif  // LIBRARIES_NACL_IO_TEST_MOUNT_MOCK_H_
+
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.cc
new file mode 100644
index 0000000..b925b56
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.cc
@@ -0,0 +1,11 @@
+/* Copyright (c) 2013 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.
+ */
+
+#include "mount_node_mock.h"
+
+MountNodeMock::MountNodeMock(Mount* mount) : MountNode(mount) {}
+
+MountNodeMock::~MountNodeMock() {}
+
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.h b/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.h
new file mode 100644
index 0000000..dbbfda1
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_node_mock.h
@@ -0,0 +1,44 @@
+/* Copyright (c) 2013 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.
+ */
+
+#ifndef LIBRARIES_NACL_IO_TEST_MOUNT_NODE_MOCK_H_
+#define LIBRARIES_NACL_IO_TEST_MOUNT_NODE_MOCK_H_
+
+#include "gmock/gmock.h"
+
+#include "nacl_io/mount.h"
+
+class MountNodeMock : public MountNode {
+ public:
+  explicit MountNodeMock(Mount*);
+  virtual ~MountNodeMock();
+
+  MOCK_METHOD1(Init, Error(int));
+  MOCK_METHOD0(Destroy, void());
+  MOCK_METHOD0(FSync, Error());
+  MOCK_METHOD1(FTruncate, Error(off_t));
+  MOCK_METHOD4(GetDents, Error(size_t, struct dirent*, size_t, int*));
+  MOCK_METHOD1(GetStat, Error(struct stat*));
+  MOCK_METHOD2(Ioctl, Error(int, char*));
+  MOCK_METHOD4(Read, Error(size_t, void*, size_t, int*));
+  MOCK_METHOD4(Write, Error(size_t, const void*, size_t, int*));
+  MOCK_METHOD6(MMap, Error(void*, size_t, int, int, size_t, void**));
+  MOCK_METHOD0(GetLinks, int());
+  MOCK_METHOD0(GetMode, int());
+  MOCK_METHOD0(GetType, int());
+  MOCK_METHOD1(GetSize, Error(size_t*));
+  MOCK_METHOD0(IsaDir, bool());
+  MOCK_METHOD0(IsaFile, bool());
+  MOCK_METHOD0(IsaTTY, bool());
+  MOCK_METHOD0(ChildCount, int());
+  MOCK_METHOD2(AddChild, Error(const std::string&, const ScopedMountNode&));
+  MOCK_METHOD1(RemoveChild, Error(const std::string&));
+  MOCK_METHOD2(FindChild, Error(const std::string&, ScopedMountNode*));
+  MOCK_METHOD0(Link, void());
+  MOCK_METHOD0(Unlink, void());
+};
+
+#endif  // LIBRARIES_NACL_IO_TEST_MOUNT_NODE_MOCK_H_
+
diff --git a/native_client_sdk/src/libraries/sdk_util/scoped_ref.h b/native_client_sdk/src/libraries/sdk_util/scoped_ref.h
index d446325..0bbba71 100644
--- a/native_client_sdk/src/libraries/sdk_util/scoped_ref.h
+++ b/native_client_sdk/src/libraries/sdk_util/scoped_ref.h
@@ -30,7 +30,8 @@ class ScopedRefBase {
   RefObject* ptr_;
 };
 
-template<class T> class ScopedRef : public ScopedRefBase {
+template <class T>
+class ScopedRef : public ScopedRefBase {
  public:
   ScopedRef() {}
   ScopedRef(const ScopedRef& ptr) { reset(ptr.get()); }
@@ -41,7 +42,13 @@ template<class T> class ScopedRef : public ScopedRefBase {
     return *this;
   }
 
-  template<typename U> ScopedRef& operator=(const ScopedRef<U>& ptr) {
+  template <typename U>
+  ScopedRef(const ScopedRef<U>& ptr) {
+    reset(ptr.get());
+  }
+
+  template <typename U>
+  ScopedRef& operator=(const ScopedRef<U>& ptr) {
     reset(ptr.get());
     return *this;
   }
@@ -49,17 +56,19 @@ template<class T> class ScopedRef : public ScopedRefBase {
   void reset(T* obj = NULL) { ScopedRefBase::reset(obj); }
   T* get() const { return static_cast<T*>(ptr_); }
 
-  template<typename U> bool operator==(const ScopedRef<U>& p) const {
+  template <typename U>
+  bool operator==(const ScopedRef<U>& p) const {
     return get() == p.get();
   }
 
-  template<typename U> bool operator!=(const ScopedRef<U>& p) const {
+  template <typename U>
+  bool operator!=(const ScopedRef<U>& p) const {
     return get() != p.get();
   }
 
  public:
   T& operator*() const { return *get(); }
-  T* operator->() const  { return get(); }
+  T* operator->() const { return get(); }
 
 #ifndef __llvm__
  private:
@@ -68,16 +77,15 @@ template<class T> class ScopedRef : public ScopedRefBase {
 
  public:
   operator bool_as_func_ptr() const {
-    return (ptr_ != NULL) ?
-      &ScopedRef::bool_as_func_impl : 0;
+    return (ptr_ != NULL) ? &ScopedRef::bool_as_func_impl : 0;
   }
 #else
   /*
    * TODO Remove when bug 3514 is fixed see:
    * https://code.google.com/p/nativeclient/issues/detail?id=3514
    */
-  operator T*() const { return get(); };
+  operator T*() const { return get(); }
 #endif
 };
 
-#endif // LIBRARIES_SDK_UTIL_SCOPED_REF_H_
+#endif  // LIBRARIES_SDK_UTIL_SCOPED_REF_H_