ScopedTempDir does not allow multiple Create* or Set calls without intervening Delete/Take calls.

BUG=None
TEST=base_unittests --gtest_filter="*ScopedTempDir*", all other tests pass.

Review URL: http://codereview.chromium.org/3980006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63641 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 32 insertions, 6 deletions

diff --git a/base/scoped_temp_dir.cc b/base/scoped_temp_dir.cc
index a510ddf..5cd13b4 100644
--- a/base/scoped_temp_dir.cc
+++ b/base/scoped_temp_dir.cc
@@ -15,6 +15,9 @@ ScopedTempDir::~ScopedTempDir() {
 }
 
 bool ScopedTempDir::CreateUniqueTempDir() {
+  if (!path_.empty())
+    return false;
+
   // This "scoped_dir" prefix is only used on Windows and serves as a template
   // for the unique name.
   if (!file_util::CreateNewTempDirectory(FILE_PATH_LITERAL("scoped_dir"),
@@ -25,7 +28,10 @@ bool ScopedTempDir::CreateUniqueTempDir() {
 }
 
 bool ScopedTempDir::CreateUniqueTempDirUnderPath(const FilePath& base_path) {
-  // If |path| does not exist, create it.
+  if (!path_.empty())
+    return false;
+
+  // If |base_path| does not exist, create it.
   if (!file_util::CreateDirectory(base_path))
     return false;
 
@@ -33,18 +39,20 @@ bool ScopedTempDir::CreateUniqueTempDirUnderPath(const FilePath& base_path) {
   if (!file_util::CreateTemporaryDirInDir(
           base_path,
           FILE_PATH_LITERAL("scoped_dir_"),
-          &path_)) {
+          &path_))
     return false;
-  }
+
   return true;
 }
 
 bool ScopedTempDir::Set(const FilePath& path) {
-  DCHECK(path_.empty());
+  if (!path_.empty())
+    return false;
+
   if (!file_util::DirectoryExists(path) &&
-      !file_util::CreateDirectory(path)) {
+      !file_util::CreateDirectory(path))
     return false;
-  }
+
   path_ = path;
   return true;
 }
diff --git a/base/scoped_temp_dir.h b/base/scoped_temp_dir.h
index 66d52f6..6845562 100644
--- a/base/scoped_temp_dir.h
+++ b/base/scoped_temp_dir.h
@@ -11,6 +11,10 @@
 // deletion occurs during the destructor, no further error handling is possible
 // if the directory fails to be deleted.  As a result, deletion is not
 // guaranteed by this class.
+//
+// Multiple calls to the methods which establish a temporary directory
+// (CreateUniqueTempDir, CreateUniqueTempDirUnderPath, and Set) must have
+// intervening calls to Delete or Take, or the calls will fail.
 
 #include "base/file_path.h"
 
diff --git a/base/scoped_temp_dir_unittest.cc b/base/scoped_temp_dir_unittest.cc
index 4be0d07..cf5fed3 100644
--- a/base/scoped_temp_dir_unittest.cc
+++ b/base/scoped_temp_dir_unittest.cc
@@ -73,3 +73,17 @@ TEST(ScopedTempDir, UniqueTempDirUnderPath) {
   }
   EXPECT_FALSE(file_util::DirectoryExists(test_path));
 }
+
+TEST(ScopedTempDir, MultipleInvocations) {
+  ScopedTempDir dir;
+  EXPECT_TRUE(dir.CreateUniqueTempDir());
+  EXPECT_FALSE(dir.CreateUniqueTempDir());
+  dir.Delete();
+  EXPECT_TRUE(dir.CreateUniqueTempDir());
+  EXPECT_FALSE(dir.CreateUniqueTempDir());
+  ScopedTempDir other_dir;
+  other_dir.Set(dir.Take());
+  EXPECT_TRUE(dir.CreateUniqueTempDir());
+  EXPECT_FALSE(dir.CreateUniqueTempDir());
+  EXPECT_FALSE(other_dir.CreateUniqueTempDir());
+}