Add Env::Remove{File,Dir} which obsolete Env::Delete{File,Dir}.

The "DeleteFile" method name causes pain for Windows developers, because
<windows.h> #defines a DeleteFile macro to DeleteFileW or DeleteFileA.
Current code uses workarounds, like #undefining DeleteFile everywhere an
Env is declared, implemented, or used.

This CL removes the need for workarounds by renaming Env::DeleteFile to
Env::RemoveFile. For consistency, Env::DeleteDir is also renamed to
Env::RemoveDir. A few internal methods are also renamed for consistency.
Software that supports Windows is expected to migrate any Env
implementations and usage to Remove{File,Dir}, and never use the name
Env::Delete{File,Dir} in its code.

The renaming is done in a backwards-compatible way, at the risk of
making it slightly more difficult to build a new correct Env
implementation. The backwards compatibility is achieved using the
following hacks:

1) Env::Remove{File,Dir} methods are added, with a default
    implementation that calls into Env::Delete{File,Dir}. This makes old
    Env implementations compatible with code that calls into the updated
    API.
2) The Env::Delete{File,Dir} methods are no longer pure virtuals.
    Instead, they gain a default implementation that calls into
    Env::Remove{File,Dir}. This makes updated Env implementations
    compatible with code that calls into the old API.

The cost of this approach is that it's possible to write an Env without
overriding either Rename{File,Dir} or Delete{File,Dir}, without getting
a compiler warning. However, attempting to run the test suite will
immediately fail with an infinite call stack ending in
{Remove,Delete}{File,Dir}, making developers aware of the problem.

PiperOrigin-RevId: 288710907

2 files changed, 8 insertions, 8 deletions

diff --git a/helpers/memenv/memenv.cc b/helpers/memenv/memenv.cc
index 31d2bc0..383c78b 100644
--- a/helpers/memenv/memenv.cc
+++ b/helpers/memenv/memenv.cc
@@ -309,7 +309,7 @@ class InMemoryEnv : public EnvWrapper {
     return Status::OK();
   }
 
-  void DeleteFileInternal(const std::string& fname)
+  void RemoveFileInternal(const std::string& fname)
       EXCLUSIVE_LOCKS_REQUIRED(mutex_) {
     if (file_map_.find(fname) == file_map_.end()) {
       return;
@@ -319,19 +319,19 @@ class InMemoryEnv : public EnvWrapper {
     file_map_.erase(fname);
   }
 
-  Status DeleteFile(const std::string& fname) override {
+  Status RemoveFile(const std::string& fname) override {
     MutexLock lock(&mutex_);
     if (file_map_.find(fname) == file_map_.end()) {
       return Status::IOError(fname, "File not found");
     }
 
-    DeleteFileInternal(fname);
+    RemoveFileInternal(fname);
     return Status::OK();
   }
 
   Status CreateDir(const std::string& dirname) override { return Status::OK(); }
 
-  Status DeleteDir(const std::string& dirname) override { return Status::OK(); }
+  Status RemoveDir(const std::string& dirname) override { return Status::OK(); }
 
   Status GetFileSize(const std::string& fname, uint64_t* file_size) override {
     MutexLock lock(&mutex_);
@@ -350,7 +350,7 @@ class InMemoryEnv : public EnvWrapper {
       return Status::IOError(src, "File not found");
     }
 
-    DeleteFileInternal(target);
+    RemoveFileInternal(target);
     file_map_[target] = file_map_[src];
     file_map_.erase(src);
     return Status::OK();
diff --git a/helpers/memenv/memenv_test.cc b/helpers/memenv/memenv_test.cc
index 619fe51..93186ab 100644
--- a/helpers/memenv/memenv_test.cc
+++ b/helpers/memenv/memenv_test.cc
@@ -88,12 +88,12 @@ TEST_F(MemEnvTest, Basics) {
   ASSERT_TRUE(!rand_file);
 
   // Check that deleting works.
-  ASSERT_TRUE(!env_->DeleteFile("/dir/non_existent").ok());
-  ASSERT_LEVELDB_OK(env_->DeleteFile("/dir/g"));
+  ASSERT_TRUE(!env_->RemoveFile("/dir/non_existent").ok());
+  ASSERT_LEVELDB_OK(env_->RemoveFile("/dir/g"));
   ASSERT_TRUE(!env_->FileExists("/dir/g"));
   ASSERT_LEVELDB_OK(env_->GetChildren("/dir", &children));
   ASSERT_EQ(0, children.size());
-  ASSERT_LEVELDB_OK(env_->DeleteDir("/dir"));
+  ASSERT_LEVELDB_OK(env_->RemoveDir("/dir"));
 }
 
 TEST_F(MemEnvTest, ReadWrite) {