Move FileSystem functions out of Host and into their own classes.

More specifically, this change can be summarized as follows:
1) Makes an lldbHostPosix library which contains code common to
   all posix platforms.
2) Creates Host/FileSystem.h which defines a common FileSystem
   interface.
3) Implements FileSystem.h in Host/windows and Host/posix.
4) Creates Host/FileCache.h, implemented in Host/common, which
   defines a class useful for storing handles to open files needed
   by the debugger.

Differential Revision: http://reviews.llvm.org/D4889

llvm-svn: 215775
diff --git a/lldb/source/Host/CMakeLists.txt b/lldb/source/Host/CMakeLists.txt
index d203d0b..5f8a2f6 100644
--- a/lldb/source/Host/CMakeLists.txt
+++ b/lldb/source/Host/CMakeLists.txt
@@ -1,11 +1,15 @@
 add_subdirectory(common)
 
-if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
-  add_subdirectory(macosx)
-elseif (CMAKE_SYSTEM_NAME MATCHES "Linux")
-  add_subdirectory(linux)
-elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
-  add_subdirectory(freebsd)
-elseif (CMAKE_SYSTEM_NAME MATCHES "Windows")
+if (CMAKE_SYSTEM_NAME MATCHES "Windows")
   add_subdirectory(windows)
+else()
+	add_subdirectory(posix)
+
+	if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
+		add_subdirectory(macosx)
+	elseif (CMAKE_SYSTEM_NAME MATCHES "Linux")
+		add_subdirectory(linux)
+	elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+		add_subdirectory(freebsd)
+  endif()
 endif()
diff --git a/lldb/source/Host/common/CMakeLists.txt b/lldb/source/Host/common/CMakeLists.txt
index 2e355ee..d71f18d 100644
--- a/lldb/source/Host/common/CMakeLists.txt
+++ b/lldb/source/Host/common/CMakeLists.txt
@@ -5,6 +5,7 @@
   DynamicLibrary.cpp
   Editline.cpp
   File.cpp
+	FileCache.cpp
   FileSpec.cpp
   Host.cpp
   IOObject.cpp
diff --git a/lldb/source/Host/common/FileCache.cpp b/lldb/source/Host/common/FileCache.cpp
new file mode 100644
index 0000000..96b2a2e
--- /dev/null
+++ b/lldb/source/Host/common/FileCache.cpp
@@ -0,0 +1,127 @@
+//===-- FileCache.cpp -------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/FileCache.h"
+
+#include "lldb/Host/File.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+FileCache *FileCache::m_instance = nullptr;
+
+FileCache &
+FileCache::GetInstance()
+{
+    if (m_instance == nullptr)
+        m_instance = new FileCache();
+
+    return *m_instance;
+}
+
+lldb::user_id_t
+FileCache::OpenFile(const FileSpec &file_spec, uint32_t flags, uint32_t mode, Error &error)
+{
+    std::string path(file_spec.GetPath());
+    if (path.empty())
+    {
+        error.SetErrorString("empty path");
+        return UINT64_MAX;
+    }
+    FileSP file_sp(new File());
+    error = file_sp->Open(path.c_str(), flags, mode);
+    if (file_sp->IsValid() == false)
+        return UINT64_MAX;
+    lldb::user_id_t fd = file_sp->GetDescriptor();
+    m_cache[fd] = file_sp;
+    return fd;
+}
+
+bool
+FileCache::CloseFile(lldb::user_id_t fd, Error &error)
+{
+    if (fd == UINT64_MAX)
+    {
+        error.SetErrorString("invalid file descriptor");
+        return false;
+    }
+    FDToFileMap::iterator pos = m_cache.find(fd);
+    if (pos == m_cache.end())
+    {
+        error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
+        return false;
+    }
+    FileSP file_sp = pos->second;
+    if (!file_sp)
+    {
+        error.SetErrorString("invalid host backing file");
+        return false;
+    }
+    error = file_sp->Close();
+    m_cache.erase(pos);
+    return error.Success();
+}
+
+uint64_t
+FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset, const void *src, uint64_t src_len, Error &error)
+{
+    if (fd == UINT64_MAX)
+    {
+        error.SetErrorString("invalid file descriptor");
+        return UINT64_MAX;
+    }
+    FDToFileMap::iterator pos = m_cache.find(fd);
+    if (pos == m_cache.end())
+    {
+        error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
+        return false;
+    }
+    FileSP file_sp = pos->second;
+    if (!file_sp)
+    {
+        error.SetErrorString("invalid host backing file");
+        return UINT64_MAX;
+    }
+    if (static_cast<uint64_t>(file_sp->SeekFromStart(offset, &error)) != offset || error.Fail())
+        return UINT64_MAX;
+    size_t bytes_written = src_len;
+    error = file_sp->Write(src, bytes_written);
+    if (error.Fail())
+        return UINT64_MAX;
+    return bytes_written;
+}
+
+uint64_t
+FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst, uint64_t dst_len, Error &error)
+{
+    if (fd == UINT64_MAX)
+    {
+        error.SetErrorString("invalid file descriptor");
+        return UINT64_MAX;
+    }
+    FDToFileMap::iterator pos = m_cache.find(fd);
+    if (pos == m_cache.end())
+    {
+        error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
+        return false;
+    }
+    FileSP file_sp = pos->second;
+    if (!file_sp)
+    {
+        error.SetErrorString("invalid host backing file");
+        return UINT64_MAX;
+    }
+    if (static_cast<uint64_t>(file_sp->SeekFromStart(offset, &error)) != offset || error.Fail())
+        return UINT64_MAX;
+    size_t bytes_read = dst_len;
+    error = file_sp->Read(dst, bytes_read);
+    if (error.Fail())
+        return UINT64_MAX;
+    return bytes_read;
+}
diff --git a/lldb/source/Host/common/FileSpec.cpp b/lldb/source/Host/common/FileSpec.cpp
index 56179a3..8c4014c 100644
--- a/lldb/source/Host/common/FileSpec.cpp
+++ b/lldb/source/Host/common/FileSpec.cpp
@@ -27,22 +27,22 @@
 #include <pwd.h>
 #endif
 
+#include "lldb/Core/DataBufferHeap.h"
+#include "lldb/Core/DataBufferMemoryMap.h"
+#include "lldb/Core/RegularExpression.h"
+#include "lldb/Core/StreamString.h"
+#include "lldb/Core/Stream.h"
+#include "lldb/Host/File.h"
+#include "lldb/Host/FileSpec.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/Host.h"
+#include "lldb/Utility/CleanUp.h"
+
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Program.h"
 
-#include "lldb/Core/StreamString.h"
-#include "lldb/Host/File.h"
-#include "lldb/Host/FileSpec.h"
-#include "lldb/Host/Host.h"
-#include "lldb/Core/DataBufferHeap.h"
-#include "lldb/Core/DataBufferMemoryMap.h"
-#include "lldb/Core/RegularExpression.h"
-#include "lldb/Core/Stream.h"
-#include "lldb/Host/Host.h"
-#include "lldb/Utility/CleanUp.h"
-
 using namespace lldb;
 using namespace lldb_private;
 
@@ -166,10 +166,10 @@
     llvm::sys::fs::make_absolute(path);
 }
 
-FileSpec::FileSpec() :
-    m_directory(),
-    m_filename(),
-    m_syntax(Host::GetHostPathSyntax())
+FileSpec::FileSpec()
+    : m_directory()
+    , m_filename()
+    , m_syntax(FileSystem::GetNativePathSyntax())
 {
 }
 
@@ -233,7 +233,8 @@
 
 void FileSpec::Normalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax)
 {
-    if (syntax == ePathSyntaxPosix || (syntax == ePathSyntaxHostNative && Host::GetHostPathSyntax() == ePathSyntaxPosix))
+    if (syntax == ePathSyntaxPosix ||
+        (syntax == ePathSyntaxHostNative && FileSystem::GetNativePathSyntax() == ePathSyntaxPosix))
         return;
 
     std::replace(path.begin(), path.end(), '\\', '/');
@@ -241,7 +242,8 @@
 
 void FileSpec::DeNormalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax)
 {
-    if (syntax == ePathSyntaxPosix || (syntax == ePathSyntaxHostNative && Host::GetHostPathSyntax() == ePathSyntaxPosix))
+    if (syntax == ePathSyntaxPosix ||
+        (syntax == ePathSyntaxHostNative && FileSystem::GetNativePathSyntax() == ePathSyntaxPosix))
         return;
 
     std::replace(path.begin(), path.end(), '/', '\\');
@@ -258,7 +260,7 @@
     m_filename.Clear();
     m_directory.Clear();
     m_is_resolved = false;
-    m_syntax = (syntax == ePathSyntaxHostNative) ? Host::GetHostPathSyntax() : syntax;
+    m_syntax = (syntax == ePathSyntaxHostNative) ? FileSystem::GetNativePathSyntax() : syntax;
 
     if (pathname == NULL || pathname[0] == '\0')
         return;
@@ -587,7 +589,7 @@
 {
     uint32_t file_permissions = 0;
     if (*this)
-        Host::GetFilePermissions(GetPath().c_str(), file_permissions);
+        FileSystem::GetFilePermissions(GetPath().c_str(), file_permissions);
     return file_permissions;
 }
 
diff --git a/lldb/source/Host/common/Host.cpp b/lldb/source/Host/common/Host.cpp
index 33df16f..885104fec 100644
--- a/lldb/source/Host/common/Host.cpp
+++ b/lldb/source/Host/common/Host.cpp
@@ -67,6 +67,7 @@
 #include "lldb/Host/Config.h"
 #include "lldb/Host/Endian.h"
 #include "lldb/Host/FileSpec.h"
+#include "lldb/Host/FileSystem.h"
 #include "lldb/Host/Mutex.h"
 #include "lldb/Target/FileAction.h"
 #include "lldb/Target/Process.h"
@@ -841,16 +842,6 @@
 
 #endif
 
-FileSpec::PathSyntax
-Host::GetHostPathSyntax()
-{
-#if defined(_WIN32)
-    return FileSpec::ePathSyntaxWindows;
-#else
-    return FileSpec::ePathSyntaxPosix;
-#endif
-}
-
 FileSpec
 Host::GetUserProfileFileSpec ()
 {
@@ -1080,7 +1071,7 @@
         // Remove the LLDB temporary directory if we have one. Set "recurse" to
         // true to all files that were created for the LLDB process can be cleaned up.
         const bool recurse = true;
-        Host::RemoveDirectory(tmpdir_file_spec.GetDirectory().GetCString(), recurse);
+        FileSystem::DeleteDirectory(tmpdir_file_spec.GetDirectory().GetCString(), recurse);
     }
 }
 
@@ -1384,10 +1375,12 @@
                 {
                     StreamString pid_tmpdir;
                     pid_tmpdir.Printf("%s/lldb", tmpdir_cstr);
-                    if (Host::MakeDirectory(pid_tmpdir.GetString().c_str(), eFilePermissionsDirectoryDefault).Success())
+                    if (FileSystem::MakeDirectory(pid_tmpdir.GetString().c_str(), eFilePermissionsDirectoryDefault)
+                            .Success())
                     {
                         pid_tmpdir.Printf("/%" PRIu64, Host::GetCurrentProcessID());
-                        if (Host::MakeDirectory(pid_tmpdir.GetString().c_str(), eFilePermissionsDirectoryDefault).Success())
+                        if (FileSystem::MakeDirectory(pid_tmpdir.GetString().c_str(), eFilePermissionsDirectoryDefault)
+                                .Success())
                         {
                             // Make an atexit handler to clean up the process specify LLDB temp dir
                             // and all of its contents.
@@ -1960,10 +1953,7 @@
             const FileAction *launch_file_action = launch_info.GetFileActionAtIndex(i);
             if (launch_file_action)
             {
-                if (!AddPosixSpawnFileAction (&file_actions,
-                                                                             launch_file_action,
-                                                                             log,
-                                                                             error))
+                if (!AddPosixSpawnFileAction(&file_actions, launch_file_action, log, error))
                     return error;
             }
         }
@@ -2033,7 +2023,8 @@
     return error;
 }
 
-bool Host::AddPosixSpawnFileAction(void *_file_actions, const FileAction *info, Log *log, Error &error)
+bool
+Host::AddPosixSpawnFileAction(void *_file_actions, const FileAction *info, Log *log, Error &error)
 {
     if (info == NULL)
         return false;
@@ -2042,57 +2033,59 @@
 
     switch (info->GetAction())
     {
-    case FileAction::eFileActionNone:
-        error.Clear();
-        break;
+        case FileAction::eFileActionNone:
+            error.Clear();
+            break;
 
-    case FileAction::eFileActionClose:
-        if (info->GetFD() == -1)
-            error.SetErrorString("invalid fd for posix_spawn_file_actions_addclose(...)");
-        else
-        {
-            error.SetError(::posix_spawn_file_actions_addclose(file_actions, info->GetFD()), eErrorTypePOSIX);
-            if (log && (error.Fail() || log))
-                error.PutToLog(log, "posix_spawn_file_actions_addclose (action=%p, fd=%i)",
-                               static_cast<void *>(file_actions), info->GetFD());
-        }
-        break;
+        case FileAction::eFileActionClose:
+            if (info->GetFD() == -1)
+                error.SetErrorString("invalid fd for posix_spawn_file_actions_addclose(...)");
+            else
+            {
+                error.SetError(::posix_spawn_file_actions_addclose(file_actions, info->GetFD()), eErrorTypePOSIX);
+                if (log && (error.Fail() || log))
+                    error.PutToLog(log, "posix_spawn_file_actions_addclose (action=%p, fd=%i)",
+                                   static_cast<void *>(file_actions), info->GetFD());
+            }
+            break;
 
-    case FileAction::eFileActionDuplicate:
-        if (info->GetFD() == -1)
-            error.SetErrorString("invalid fd for posix_spawn_file_actions_adddup2(...)");
-        else if (info->GetActionArgument() == -1)
-            error.SetErrorString("invalid duplicate fd for posix_spawn_file_actions_adddup2(...)");
-        else
-        {
-            error.SetError(::posix_spawn_file_actions_adddup2(file_actions, info->GetFD(), info->GetActionArgument()),
-                           eErrorTypePOSIX);
-            if (log && (error.Fail() || log))
-                error.PutToLog(log, "posix_spawn_file_actions_adddup2 (action=%p, fd=%i, dup_fd=%i)",
-                               static_cast<void *>(file_actions), info->GetFD(), info->GetActionArgument());
-        }
-        break;
+        case FileAction::eFileActionDuplicate:
+            if (info->GetFD() == -1)
+                error.SetErrorString("invalid fd for posix_spawn_file_actions_adddup2(...)");
+            else if (info->GetActionArgument() == -1)
+                error.SetErrorString("invalid duplicate fd for posix_spawn_file_actions_adddup2(...)");
+            else
+            {
+                error.SetError(
+                    ::posix_spawn_file_actions_adddup2(file_actions, info->GetFD(), info->GetActionArgument()),
+                    eErrorTypePOSIX);
+                if (log && (error.Fail() || log))
+                    error.PutToLog(log, "posix_spawn_file_actions_adddup2 (action=%p, fd=%i, dup_fd=%i)",
+                                   static_cast<void *>(file_actions), info->GetFD(), info->GetActionArgument());
+            }
+            break;
 
-    case FileAction::eFileActionOpen:
-        if (info->GetFD() == -1)
-            error.SetErrorString("invalid fd in posix_spawn_file_actions_addopen(...)");
-        else
-        {
-            int oflag = info->GetActionArgument();
+        case FileAction::eFileActionOpen:
+            if (info->GetFD() == -1)
+                error.SetErrorString("invalid fd in posix_spawn_file_actions_addopen(...)");
+            else
+            {
+                int oflag = info->GetActionArgument();
 
-            mode_t mode = 0;
+                mode_t mode = 0;
 
-            if (oflag & O_CREAT)
-                mode = 0640;
+                if (oflag & O_CREAT)
+                    mode = 0640;
 
-            error.SetError(
-                ::posix_spawn_file_actions_addopen(file_actions, info->GetFD(), info->GetPath(), oflag, mode),
-                eErrorTypePOSIX);
-            if (error.Fail() || log)
-                error.PutToLog(log, "posix_spawn_file_actions_addopen (action=%p, fd=%i, path='%s', oflag=%i, mode=%i)",
-                               static_cast<void *>(file_actions), info->GetFD(), info->GetPath(), oflag, mode);
-        }
-        break;
+                error.SetError(
+                    ::posix_spawn_file_actions_addopen(file_actions, info->GetFD(), info->GetPath(), oflag, mode),
+                    eErrorTypePOSIX);
+                if (error.Fail() || log)
+                    error.PutToLog(log,
+                                   "posix_spawn_file_actions_addopen (action=%p, fd=%i, path='%s', oflag=%i, mode=%i)",
+                                   static_cast<void *>(file_actions), info->GetFD(), info->GetPath(), oflag, mode);
+            }
+            break;
     }
     return error.Success();
 }
@@ -2266,298 +2259,3 @@
 }
 
 #endif
-
-
-#if !defined(_WIN32)
-Error
-Host::MakeDirectory (const char* path, uint32_t file_permissions)
-{
-    Error error;
-    if (path && path[0])
-    {
-        if (::mkdir(path, file_permissions) != 0)
-        {
-            error.SetErrorToErrno();
-            switch (error.GetError())
-            {
-            case ENOENT:
-                {
-                    // Parent directory doesn't exist, so lets make it if we can
-                    FileSpec spec(path, false);
-                    if (spec.GetDirectory() && spec.GetFilename())
-                    {
-                        // Make the parent directory and try again
-                        Error error2 = Host::MakeDirectory(spec.GetDirectory().GetCString(), file_permissions);
-                        if (error2.Success())
-                        {
-                            // Try and make the directory again now that the parent directory was made successfully
-                            if (::mkdir(path, file_permissions) == 0)
-                                error.Clear();
-                            else
-                                error.SetErrorToErrno();
-                        }
-                    }
-                }
-                break;
-            case EEXIST:
-                {
-                    FileSpec path_spec(path, false);
-                    if (path_spec.IsDirectory())
-                        error.Clear(); // It is a directory and it already exists
-                }
-                break;
-            }
-        }
-    }
-    else
-    {
-        error.SetErrorString("empty path");
-    }
-    return error;
-}
-                                                                    
-Error
-Host::RemoveDirectory (const char* path, bool recurse)
-{
-    Error error;
-    if (path && path[0])
-    {
-        if (recurse)
-        {
-            StreamString command;
-            command.Printf("rm -rf \"%s\"", path);
-            int status = ::system(command.GetString().c_str());
-            if (status != 0)
-                error.SetError(status, eErrorTypeGeneric);
-        }
-        else
-        {
-            if (::rmdir(path) != 0)
-                error.SetErrorToErrno();
-        }
-    }
-    else
-    {
-        error.SetErrorString("empty path");
-    }
-    return error;
-}
-
-Error
-Host::GetFilePermissions (const char* path, uint32_t &file_permissions)
-{
-    Error error;
-    struct stat file_stats;
-    if (::stat (path, &file_stats) == 0)
-    {
-        // The bits in "st_mode" currently match the definitions
-        // for the file mode bits in unix.
-        file_permissions = file_stats.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO);
-    }
-    else
-    {
-        error.SetErrorToErrno();
-    }
-    return error;
-}
-
-Error
-Host::SetFilePermissions (const char* path, uint32_t file_permissions)
-{
-    Error error;
-    if (::chmod(path, file_permissions) != 0)
-        error.SetErrorToErrno();
-    return error;
-}
-
-Error
-Host::Symlink (const char *src, const char *dst)
-{
-    Error error;
-    if (::symlink(dst, src) == -1)
-        error.SetErrorToErrno();
-    return error;
-}
-
-Error
-Host::Unlink (const char *path)
-{
-    Error error;
-    if (::unlink(path) == -1)
-        error.SetErrorToErrno();
-    return error;
-}
-
-Error
-Host::Readlink (const char *path, char *buf, size_t buf_len)
-{
-    Error error;
-    ssize_t count = ::readlink(path, buf, buf_len);
-    if (count < 0)
-        error.SetErrorToErrno();
-    else if (static_cast<size_t>(count) < (buf_len-1))
-        buf[count] = '\0'; // Success
-    else
-        error.SetErrorString("'buf' buffer is too small to contain link contents");
-    return error;
-}
-
-
-#endif
-
-typedef std::map<lldb::user_id_t, lldb::FileSP> FDToFileMap;
-FDToFileMap& GetFDToFileMap()
-{
-    static FDToFileMap g_fd2filemap;
-    return g_fd2filemap;
-}
-
-lldb::user_id_t
-Host::OpenFile (const FileSpec& file_spec,
-                uint32_t flags,
-                uint32_t mode,
-                Error &error)
-{
-    std::string path (file_spec.GetPath());
-    if (path.empty())
-    {
-        error.SetErrorString("empty path");
-        return UINT64_MAX;
-    }
-    FileSP file_sp(new File());
-    error = file_sp->Open(path.c_str(),flags,mode);
-    if (file_sp->IsValid() == false)
-        return UINT64_MAX;
-    lldb::user_id_t fd = file_sp->GetDescriptor();
-    GetFDToFileMap()[fd] = file_sp;
-    return fd;
-}
-
-bool
-Host::CloseFile (lldb::user_id_t fd, Error &error)
-{
-    if (fd == UINT64_MAX)
-    {
-        error.SetErrorString ("invalid file descriptor");
-        return false;
-    }
-    FDToFileMap& file_map = GetFDToFileMap();
-    FDToFileMap::iterator pos = file_map.find(fd);
-    if (pos == file_map.end())
-    {
-        error.SetErrorStringWithFormat ("invalid host file descriptor %" PRIu64, fd);
-        return false;
-    }
-    FileSP file_sp = pos->second;
-    if (!file_sp)
-    {
-        error.SetErrorString ("invalid host backing file");
-        return false;
-    }
-    error = file_sp->Close();
-    file_map.erase(pos);
-    return error.Success();
-}
-
-uint64_t
-Host::WriteFile (lldb::user_id_t fd, uint64_t offset, const void* src, uint64_t src_len, Error &error)
-{
-    if (fd == UINT64_MAX)
-    {
-        error.SetErrorString ("invalid file descriptor");
-        return UINT64_MAX;
-    }
-    FDToFileMap& file_map = GetFDToFileMap();
-    FDToFileMap::iterator pos = file_map.find(fd);
-    if (pos == file_map.end())
-    {
-        error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64 , fd);
-        return false;
-    }
-    FileSP file_sp = pos->second;
-    if (!file_sp)
-    {
-        error.SetErrorString ("invalid host backing file");
-        return UINT64_MAX;
-    }
-    if (static_cast<uint64_t>(file_sp->SeekFromStart(offset, &error)) != offset ||
-        error.Fail())
-        return UINT64_MAX;
-    size_t bytes_written = src_len;
-    error = file_sp->Write(src, bytes_written);
-    if (error.Fail())
-        return UINT64_MAX;
-    return bytes_written;
-}
-
-uint64_t
-Host::ReadFile (lldb::user_id_t fd, uint64_t offset, void* dst, uint64_t dst_len, Error &error)
-{
-    if (fd == UINT64_MAX)
-    {
-        error.SetErrorString ("invalid file descriptor");
-        return UINT64_MAX;
-    }
-    FDToFileMap& file_map = GetFDToFileMap();
-    FDToFileMap::iterator pos = file_map.find(fd);
-    if (pos == file_map.end())
-    {
-        error.SetErrorStringWithFormat ("invalid host file descriptor %" PRIu64, fd);
-        return false;
-    }
-    FileSP file_sp = pos->second;
-    if (!file_sp)
-    {
-        error.SetErrorString ("invalid host backing file");
-        return UINT64_MAX;
-    }
-    if (static_cast<uint64_t>(file_sp->SeekFromStart(offset, &error)) != offset ||
-        error.Fail())
-        return UINT64_MAX;
-    size_t bytes_read = dst_len;
-    error = file_sp->Read(dst ,bytes_read);
-    if (error.Fail())
-        return UINT64_MAX;
-    return bytes_read;
-}
-
-lldb::user_id_t
-Host::GetFileSize (const FileSpec& file_spec)
-{
-    return file_spec.GetByteSize();
-}
-
-bool
-Host::GetFileExists (const FileSpec& file_spec)
-{
-    return file_spec.Exists();
-}
-
-bool
-Host::CalculateMD5 (const FileSpec& file_spec,
-                    uint64_t &low,
-                    uint64_t &high)
-{
-#if defined (__APPLE__)
-    StreamString md5_cmd_line;
-    md5_cmd_line.Printf("md5 -q '%s'", file_spec.GetPath().c_str());
-    std::string hash_string;
-    Error err = Host::RunShellCommand(md5_cmd_line.GetData(), NULL, NULL, NULL, &hash_string, 60);
-    if (err.Fail())
-        return false;
-    // a correctly formed MD5 is 16-bytes, that is 32 hex digits
-    // if the output is any other length it is probably wrong
-    if (hash_string.size() != 32)
-        return false;
-    std::string part1(hash_string,0,16);
-    std::string part2(hash_string,16);
-    const char* part1_cstr = part1.c_str();
-    const char* part2_cstr = part2.c_str();
-    high = ::strtoull(part1_cstr, NULL, 16);
-    low = ::strtoull(part2_cstr, NULL, 16);
-    return true;
-#else
-    // your own MD5 implementation here
-    return false;
-#endif
-}
diff --git a/lldb/source/Host/common/Socket.cpp b/lldb/source/Host/common/Socket.cpp
index 86bea42..31e3228 100644
--- a/lldb/source/Host/common/Socket.cpp
+++ b/lldb/source/Host/common/Socket.cpp
@@ -12,6 +12,7 @@
 #include "lldb/Core/Log.h"
 #include "lldb/Core/RegularExpression.h"
 #include "lldb/Host/Config.h"
+#include "lldb/Host/FileSystem.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Host/SocketAddress.h"
 #include "lldb/Host/TimeValue.h"
@@ -442,7 +443,7 @@
     saddr_un.sun_len = SUN_LEN (&saddr_un);
 #endif
 
-    Host::Unlink (name.data());
+    FileSystem::Unlink(name.data());
     bool success = false;
     if (::bind (listen_fd, (struct sockaddr *)&saddr_un, SUN_LEN (&saddr_un)) == 0) 
     {
diff --git a/lldb/source/Host/posix/CMakeLists.txt b/lldb/source/Host/posix/CMakeLists.txt
new file mode 100644
index 0000000..c783764
--- /dev/null
+++ b/lldb/source/Host/posix/CMakeLists.txt
@@ -0,0 +1,5 @@
+set(LLVM_NO_RTTI 1)
+
+add_lldb_library(lldbHostPosix
+  FileSystem.cpp
+  )
diff --git a/lldb/source/Host/posix/FileSystem.cpp b/lldb/source/Host/posix/FileSystem.cpp
new file mode 100644
index 0000000..5713168
--- /dev/null
+++ b/lldb/source/Host/posix/FileSystem.cpp
@@ -0,0 +1,201 @@
+//===-- FileSystem.cpp ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/FileSystem.h"
+
+// C includes
+#include <sys/stat.h>
+#include <sys/types.h>
+
+// lldb Includes
+#include "lldb/Core/Error.h"
+#include "lldb/Core/StreamString.h"
+#include "lldb/Host/Host.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+FileSpec::PathSyntax
+FileSystem::GetNativePathSyntax()
+{
+    return FileSpec::ePathSyntaxPosix;
+}
+
+Error
+FileSystem::MakeDirectory(const char *path, uint32_t file_permissions)
+{
+    Error error;
+    if (path && path[0])
+    {
+        if (::mkdir(path, file_permissions) != 0)
+        {
+            error.SetErrorToErrno();
+            switch (error.GetError())
+            {
+                case ENOENT:
+                {
+                    // Parent directory doesn't exist, so lets make it if we can
+                    FileSpec spec(path, false);
+                    if (spec.GetDirectory() && spec.GetFilename())
+                    {
+                        // Make the parent directory and try again
+                        Error error2 = MakeDirectory(spec.GetDirectory().GetCString(), file_permissions);
+                        if (error2.Success())
+                        {
+                            // Try and make the directory again now that the parent directory was made successfully
+                            if (::mkdir(path, file_permissions) == 0)
+                                error.Clear();
+                            else
+                                error.SetErrorToErrno();
+                        }
+                    }
+                }
+                break;
+
+                case EEXIST:
+                {
+                    FileSpec path_spec(path, false);
+                    if (path_spec.IsDirectory())
+                        error.Clear(); // It is a directory and it already exists
+                }
+                break;
+            }
+        }
+    }
+    else
+    {
+        error.SetErrorString("empty path");
+    }
+    return error;
+}
+
+Error
+FileSystem::DeleteDirectory(const char *path, bool recurse)
+{
+    Error error;
+    if (path && path[0])
+    {
+        if (recurse)
+        {
+            StreamString command;
+            command.Printf("rm -rf \"%s\"", path);
+            int status = ::system(command.GetString().c_str());
+            if (status != 0)
+                error.SetError(status, eErrorTypeGeneric);
+        }
+        else
+        {
+            if (::rmdir(path) != 0)
+                error.SetErrorToErrno();
+        }
+    }
+    else
+    {
+        error.SetErrorString("empty path");
+    }
+    return error;
+}
+
+Error
+FileSystem::GetFilePermissions(const char *path, uint32_t &file_permissions)
+{
+    Error error;
+    struct stat file_stats;
+    if (::stat(path, &file_stats) == 0)
+    {
+        // The bits in "st_mode" currently match the definitions
+        // for the file mode bits in unix.
+        file_permissions = file_stats.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO);
+    }
+    else
+    {
+        error.SetErrorToErrno();
+    }
+    return error;
+}
+
+Error
+FileSystem::SetFilePermissions(const char *path, uint32_t file_permissions)
+{
+    Error error;
+    if (::chmod(path, file_permissions) != 0)
+        error.SetErrorToErrno();
+    return error;
+}
+
+lldb::user_id_t
+FileSystem::GetFileSize(const FileSpec &file_spec)
+{
+    return file_spec.GetByteSize();
+}
+
+bool
+FileSystem::GetFileExists(const FileSpec &file_spec)
+{
+    return file_spec.Exists();
+}
+
+Error
+FileSystem::Symlink(const char *src, const char *dst)
+{
+    Error error;
+    if (::symlink(dst, src) == -1)
+        error.SetErrorToErrno();
+    return error;
+}
+
+Error
+FileSystem::Unlink(const char *path)
+{
+    Error error;
+    if (::unlink(path) == -1)
+        error.SetErrorToErrno();
+    return error;
+}
+
+Error
+FileSystem::Readlink(const char *path, char *buf, size_t buf_len)
+{
+    Error error;
+    ssize_t count = ::readlink(path, buf, buf_len);
+    if (count < 0)
+        error.SetErrorToErrno();
+    else if (static_cast<size_t>(count) < (buf_len - 1))
+        buf[count] = '\0'; // Success
+    else
+        error.SetErrorString("'buf' buffer is too small to contain link contents");
+    return error;
+}
+
+bool
+FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t &low, uint64_t &high)
+{
+#if defined(__APPLE__)
+    StreamString md5_cmd_line;
+    md5_cmd_line.Printf("md5 -q '%s'", file_spec.GetPath().c_str());
+    std::string hash_string;
+    Error err = Host::RunShellCommand(md5_cmd_line.GetData(), NULL, NULL, NULL, &hash_string, 60);
+    if (err.Fail())
+        return false;
+    // a correctly formed MD5 is 16-bytes, that is 32 hex digits
+    // if the output is any other length it is probably wrong
+    if (hash_string.size() != 32)
+        return false;
+    std::string part1(hash_string, 0, 16);
+    std::string part2(hash_string, 16);
+    const char *part1_cstr = part1.c_str();
+    const char *part2_cstr = part2.c_str();
+    high = ::strtoull(part1_cstr, NULL, 16);
+    low = ::strtoull(part2_cstr, NULL, 16);
+    return true;
+#else
+    // your own MD5 implementation here
+    return false;
+#endif
+}
diff --git a/lldb/source/Host/windows/CMakeLists.txt b/lldb/source/Host/windows/CMakeLists.txt
index 2a19922..5a5ce2a 100644
--- a/lldb/source/Host/windows/CMakeLists.txt
+++ b/lldb/source/Host/windows/CMakeLists.txt
@@ -1,6 +1,7 @@
 set(LLVM_NO_RTTI 1)
 
 add_lldb_library(lldbHostWindows
+	FileSystem.cpp
   Host.cpp
   ProcessRunLock.cpp
   Mutex.cpp
diff --git a/lldb/source/Host/windows/FileSystem.cpp b/lldb/source/Host/windows/FileSystem.cpp
new file mode 100644
index 0000000..a735ff0
--- /dev/null
+++ b/lldb/source/Host/windows/FileSystem.cpp
@@ -0,0 +1,146 @@
+//===-- FileSystem.cpp ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/windows/windows.h"
+
+#include <shellapi.h>
+
+#include "lldb/Host/FileSystem.h"
+
+using namespace lldb_private;
+
+FileSpec::PathSyntax
+FileSystem::GetNativePathSyntax()
+{
+    return FileSpec::ePathSyntaxWindows;
+}
+
+Error
+FileSystem::MakeDirectory(const char *path, uint32_t file_permissions)
+{
+    // On Win32, the mode parameter is ignored, as Windows files and directories support a
+    // different permission model than POSIX.
+    Error error;
+    if (!::CreateDirectory(path, NULL))
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+    return error;
+}
+
+Error
+FileSystem::DeleteDirectory(const char *path, bool recurse)
+{
+    Error error;
+    if (!recurse)
+    {
+        BOOL result = ::RemoveDirectory(path);
+        if (!result)
+            error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+    }
+    else
+    {
+        // SHFileOperation() accepts a list of paths, and so must be double-null-terminated to
+        // indicate the end of the list.
+        std::string path_buffer(path);
+        path_buffer.push_back(0);
+
+        SHFILEOPSTRUCT shfos = {0};
+        shfos.wFunc = FO_DELETE;
+        shfos.pFrom = path_buffer.c_str();
+        shfos.fFlags = FOF_NO_UI;
+
+        int result = ::SHFileOperation(&shfos);
+        // TODO(zturner): Correctly handle the intricacies of SHFileOperation return values.
+        if (result != 0)
+            error.SetErrorStringWithFormat("SHFileOperation failed");
+    }
+    return error;
+}
+
+Error
+FileSystem::GetFilePermissions(const char *path, uint32_t &file_permissions)
+{
+    Error error;
+    error.SetErrorStringWithFormat("%s is not supported on this host", __PRETTY_FUNCTION__);
+    return error;
+}
+
+Error
+FileSystem::SetFilePermissions(const char *path, uint32_t file_permissions)
+{
+    Error error;
+    error.SetErrorStringWithFormat("%s is not supported on this host", __PRETTY_FUNCTION__);
+    return error;
+}
+
+lldb::user_id_t
+FileSystem::GetFileSize(const FileSpec &file_spec)
+{
+    return file_spec.GetByteSize();
+}
+
+bool
+FileSystem::GetFileExists(const FileSpec &file_spec)
+{
+    return file_spec.Exists();
+}
+
+Error
+FileSystem::Symlink(const char *linkname, const char *target)
+{
+    Error error;
+    DWORD attrib = ::GetFileAttributes(target);
+    if (attrib == INVALID_FILE_ATTRIBUTES)
+    {
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+        return error;
+    }
+    bool is_directory = !!(attrib & FILE_ATTRIBUTE_DIRECTORY);
+    DWORD flag = is_directory ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
+    BOOL result = ::CreateSymbolicLink(linkname, target, flag);
+    if (!result)
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+    return error;
+}
+
+Error
+FileSystem::Unlink(const char *path)
+{
+    Error error;
+    BOOL result = ::DeleteFile(path);
+    if (!result)
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+    return error;
+}
+
+Error
+FileSystem::Readlink(const char *path, char *buf, size_t buf_len)
+{
+    Error error;
+    HANDLE h = ::CreateFile(path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
+                            FILE_FLAG_OPEN_REPARSE_POINT, NULL);
+    if (h == INVALID_HANDLE_VALUE)
+    {
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+        return error;
+    }
+
+    // Subtract 1 from the path length since this function does not add a null terminator.
+    DWORD result = ::GetFinalPathNameByHandle(h, buf, buf_len - 1, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+    if (result == 0)
+        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
+
+    ::CloseHandle(h);
+    return error;
+}
+
+bool
+FileSystem::CalculateMD5(const FileSpec &file_spec, uint64_t &low, uint64_t &high)
+{
+    return false;
+}
diff --git a/lldb/source/Host/windows/Host.cpp b/lldb/source/Host/windows/Host.cpp
index bf6c1bd..9fa2652 100644
--- a/lldb/source/Host/windows/Host.cpp
+++ b/lldb/source/Host/windows/Host.cpp
@@ -25,7 +25,6 @@
 #include "lldb/Core/StreamFile.h"
 
 // Windows includes
-#include <shellapi.h>
 #include <TlHelp32.h>
 
 using namespace lldb;
@@ -124,115 +123,6 @@
 }
 
 Error
-Host::MakeDirectory (const char* path, uint32_t mode)
-{
-    // On Win32, the mode parameter is ignored, as Windows files and directories support a
-    // different permission model than POSIX.
-    Error error;
-    if (!::CreateDirectory(path, NULL))
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-    return error;
-}
-
-Error
-Host::GetFilePermissions (const char* path, uint32_t &file_permissions)
-{
-    Error error;
-    file_permissions = 0;
-    DWORD attrib = ::GetFileAttributes(path);
-    if (attrib == INVALID_FILE_ATTRIBUTES)
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-    return error;
-}
-
-Error
-Host::SetFilePermissions (const char* path, uint32_t file_permissions)
-{
-    Error error;
-    error.SetErrorStringWithFormat("%s is not supported on this host", __PRETTY_FUNCTION__);
-    return error;
-}
-
-Error
-Host::Symlink (const char *linkname, const char *target)
-{
-    Error error;
-    DWORD attrib = ::GetFileAttributes(target);
-    if (attrib == INVALID_FILE_ATTRIBUTES)
-    {
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-        return error;
-    }
-    bool is_directory = !!(attrib & FILE_ATTRIBUTE_DIRECTORY);
-    DWORD flag = is_directory ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
-    BOOL result = ::CreateSymbolicLink(linkname, target, flag);
-    if (!result)
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-    return error;
-}
-
-Error
-Host::Readlink (const char *path, char *buf, size_t buf_len)
-{
-    Error error;
-    HANDLE h = ::CreateFile(path, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, NULL);
-    if (h == INVALID_HANDLE_VALUE)
-    {
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-        return error;
-    }
-
-    // Subtract 1 from the path length since this function does not add a null terminator.
-    DWORD result = ::GetFinalPathNameByHandle(h, buf, buf_len-1, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
-    if (result == 0)
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-
-    ::CloseHandle(h);
-    return error;
-}
-
-Error
-Host::Unlink (const char *path)
-{
-    Error error;
-    BOOL result = ::DeleteFile(path);
-    if (!result)
-        error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-    return error;
-}
-
-Error
-Host::RemoveDirectory (const char* path, bool recurse)
-{
-    Error error;
-    if (!recurse)
-    {
-        BOOL result = ::RemoveDirectory(path);
-        if (!result)
-            error.SetError(::GetLastError(), lldb::eErrorTypeWin32);
-    }
-    else
-    {
-        // SHFileOperation() accepts a list of paths, and so must be double-null-terminated to
-        // indicate the end of the list.
-        std::string path_buffer(path);
-        path_buffer.push_back(0);
-
-        SHFILEOPSTRUCT shfos = {0};
-        shfos.wFunc = FO_DELETE;
-        shfos.pFrom = path_buffer.c_str();
-        shfos.fFlags = FOF_NO_UI;
-
-        int result = ::SHFileOperation(&shfos);
-        // TODO(zturner): Correctly handle the intricacies of SHFileOperation return values.
-        if (result != 0)
-            error.SetErrorStringWithFormat("SHFileOperation failed");
-    }
-    return error;
-}
-
-
-Error
 Host::LaunchProcess (ProcessLaunchInfo &launch_info)
 {
     Error error;