From 050671f8b55500a11a12e7e29ac30f47039eb30a Mon Sep 17 00:00:00 2001
From: Christopher Dykes <cdykes@fb.com>
Date: Thu, 13 Jul 2017 11:50:36 -0700
Subject: [PATCH] Add support for closing a TemporaryFile early

Summary:
The file itself will still get removed when `TemporaryFile` is destroyed, but closing it before then allows it to be read when on Windows, because `TemporaryFile` opens the temporary file with `O_EXCL`, so Windows denies read access of the file to everything else.
This is needed to fix one of the AsyncFileWriter tests on Windows.

Reviewed By: simpkins

Differential Revision: D5307719

fbshipit-source-id: bd65962cc3d34f382cc7b0b55dbf2659ed5ebfce
---
 folly/experimental/TestUtil.cpp          |  9 ++++++++-
 folly/experimental/TestUtil.h            |  1 +
 folly/experimental/test/TestUtilTest.cpp | 13 +++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/folly/experimental/TestUtil.cpp b/folly/experimental/TestUtil.cpp
index d0f39b94..cbaa3246 100644
--- a/folly/experimental/TestUtil.cpp
+++ b/folly/experimental/TestUtil.cpp
@@ -74,6 +74,13 @@ TemporaryFile::TemporaryFile(StringPiece namePrefix,
   }
 }
 
+void TemporaryFile::close() {
+  if (::close(fd_) == -1) {
+    PLOG(ERROR) << "close failed";
+  }
+  fd_ = -1;
+}
+
 const fs::path& TemporaryFile::path() const {
   CHECK(scope_ != Scope::UNLINK_IMMEDIATELY);
   DCHECK(!path_.empty());
@@ -82,7 +89,7 @@ const fs::path& TemporaryFile::path() const {
 
 TemporaryFile::~TemporaryFile() {
   if (fd_ != -1 && closeOnDestruction_) {
-    if (close(fd_) == -1) {
+    if (::close(fd_) == -1) {
       PLOG(ERROR) << "close failed";
     }
   }
diff --git a/folly/experimental/TestUtil.h b/folly/experimental/TestUtil.h
index cc110feb..2460b84b 100644
--- a/folly/experimental/TestUtil.h
+++ b/folly/experimental/TestUtil.h
@@ -54,6 +54,7 @@ class TemporaryFile {
   TemporaryFile(TemporaryFile&&) = default;
   TemporaryFile& operator=(TemporaryFile&&) = default;
 
+  void close();
   int fd() const { return fd_; }
   const fs::path& path() const;
 
diff --git a/folly/experimental/test/TestUtilTest.cpp b/folly/experimental/test/TestUtilTest.cpp
index 32196ecc..72b9ccbf 100644
--- a/folly/experimental/test/TestUtilTest.cpp
+++ b/folly/experimental/test/TestUtilTest.cpp
@@ -53,6 +53,19 @@ TEST(TemporaryFile, Simple) {
   });
 }
 
+TEST(TemporaryFile, EarlyClose) {
+  fs::path p;
+  {
+    TemporaryFile f;
+    p = f.path();
+    EXPECT_TRUE(fs::exists(p));
+    f.close();
+    EXPECT_EQ(-1, f.fd());
+    EXPECT_TRUE(fs::exists(p));
+  }
+  EXPECT_FALSE(fs::exists(p));
+}
+
 TEST(TemporaryFile, Prefix) {
   TemporaryFile f("Foo");
   EXPECT_TRUE(f.path().is_absolute());
-- 
2.34.1