[lldb-server] Improve support on Windows

Summary:
This commit contains the following changes:

  - Rewrite vfile close/read/write packet handlers with portable routines from lldb.
    This removes #if(s) and allows the handlers to work on Windows.

  - Fix a bug in File::Write. This is intended to write data at an offset to a file
    but actually writes at the current position of the file.

  - Add a default boolean argument 'should_close_fd' to FileSystem::Open to
    let the user decide whether to close the fd or not.

Reviewers: zturner, llvm-commits, labath

Reviewed By: zturner

Subscribers: Hui, labath, abidh, lldb-commits

Differential Revision: https://reviews.llvm.org/D56231

llvm-svn: 353446

1 files changed, 4 insertions, 1 deletions

diff --git a/lldb/source/Host/common/File.cpp b/lldb/source/Host/common/File.cpp
index dba6e08acb3..512e7c58702 100644
--- a/lldb/source/Host/common/File.cpp
+++ b/lldb/source/Host/common/File.cpp
@@ -178,7 +178,7 @@ Status File::Close() {
 
 void File::Clear() {
   m_stream = nullptr;
-  m_descriptor = -1;
+  m_descriptor = kInvalidDescriptor;
   m_options = 0;
   m_own_stream = false;
   m_is_interactive = m_supports_colors = m_is_real_terminal =
@@ -503,6 +503,7 @@ Status File::Read(void *buf, size_t &num_bytes, off_t &offset) {
     error.SetErrorString("invalid file handle");
   }
 #else
+  std::lock_guard<std::mutex> guard(offset_access_mutex);
   long cur = ::lseek(m_descriptor, 0, SEEK_CUR);
   SeekFromStart(offset);
   error = Read(buf, num_bytes);
@@ -602,7 +603,9 @@ Status File::Write(const void *buf, size_t &num_bytes, off_t &offset) {
       num_bytes = bytes_written;
     }
 #else
+    std::lock_guard<std::mutex> guard(offset_access_mutex);
     long cur = ::lseek(m_descriptor, 0, SEEK_CUR);
+    SeekFromStart(offset);
     error = Write(buf, num_bytes);
     long after = ::lseek(m_descriptor, 0, SEEK_CUR);