Add IsDirectory() to Env and FS (#6711)

Summary:
IsDirectory() is a common API to check whether a path is a regular file or
directory.
POSIX: call stat() and use S_ISDIR(st_mode)
Windows: PathIsDirectoryA() and PathIsDirectoryW()
HDFS: FileSystem.IsDirectory()
Java: File.IsDirectory()
...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6711

Test Plan: make check

Reviewed By: anand1976

Differential Revision: D21053520

Pulled By: riversand963

fbshipit-source-id: 680aadfd8ce982b63689190cf31b3145d5a89e27

HISTORY.md

@@ -6,6 +6,7 @@
 
 ### Public API Change
 * Add NewFileChecksumGenCrc32cFactory to the file checksum public API, such that the builtin Crc32c based file checksum generator factory can be used by applications.
+* Add IsDirectory to Env and FS to indicate if a path is a directory.
 
 ### New Features
 * Added support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism.

env/composite_env_wrapper.h

@@ -492,6 +492,12 @@ class CompositeEnvWrapper : public Env {
     return file_system_->NewLogger(fname, io_opts, result, &dbg);
   }
 
+  Status IsDirectory(const std::string& path, bool* is_dir) override {
+    IOOptions io_opts;
+    IODebugContext dbg;
+    return file_system_->IsDirectory(path, io_opts, is_dir, &dbg);
+  }
+
 #if !defined(OS_WIN) && !defined(ROCKSDB_NO_DYNAMIC_EXTENSION)
   Status LoadLibrary(const std::string& lib_name,
                      const std::string& search_path,
@@ -1081,6 +1087,10 @@ class LegacyFileSystemWrapper : public FileSystem {
                         uint64_t* diskfree, IODebugContext* /*dbg*/) override {
     return status_to_io_status(target_->GetFreeSpace(path, diskfree));
   }
+  IOStatus IsDirectory(const std::string& path, const IOOptions& /*options*/,
+                       bool* is_dir, IODebugContext* /*dbg*/) override {
+    return status_to_io_status(target_->IsDirectory(path, is_dir));
+  }
 
  private:
   Env* target_;

env/env_hdfs.cc

@@ -609,6 +609,18 @@ Status HdfsEnv::NewLogger(const std::string& fname,
   return Status::OK();
 }
 
+Status HdfsEnv::IsDirectory(const std::string& path, bool* is_dir) {
+  hdfsFileInfo* pFileInfo = hdfsGetPathInfo(fileSys_, path.c_str());
+  if (pFileInfo != nullptr) {
+    if (is_dir != nullptr) {
+      *is_dir = (pFileInfo->mKind == tObjectKindDirectory);
+    }
+    hdfsFreeFileInfo(pFileInfo, 1);
+    return Status::OK();
+  }
+  return IOError(path, errno);
+}
+
 // The factory method for creating an HDFS Env
 Status NewHdfsEnv(Env** hdfs_env, const std::string& fsname) {
   *hdfs_env = new HdfsEnv(fsname);

env/env_test.cc

@@ -1937,7 +1937,13 @@ class TestEnv : public EnvWrapper {
   int close_count;
 };
 
-class EnvTest : public testing::Test {};
+class EnvTest : public testing::Test {
+ public:
+  EnvTest() : test_directory_(test::PerThreadDBPath("env_test")) {}
+
+ protected:
+  const std::string test_directory_;
+};
 
 TEST_F(EnvTest, Close) {
   TestEnv* env = new TestEnv();
@@ -2090,6 +2096,31 @@ TEST_F(EnvTest, MultipleCompositeEnv) {
   ASSERT_EQ(env2->GetBackgroundThreads(Env::HIGH), 8);
 }
 
+TEST_F(EnvTest, IsDirectory) {
+  Status s = Env::Default()->CreateDirIfMissing(test_directory_);
+  ASSERT_OK(s);
+  const std::string test_sub_dir = test_directory_ + "sub1";
+  const std::string test_file_path = test_directory_ + "file1";
+  ASSERT_OK(Env::Default()->CreateDirIfMissing(test_sub_dir));
+  bool is_dir = false;
+  ASSERT_OK(Env::Default()->IsDirectory(test_sub_dir, &is_dir));
+  ASSERT_TRUE(is_dir);
+  {
+    std::unique_ptr<FSWritableFile> wfile;
+    s = Env::Default()->GetFileSystem()->NewWritableFile(
+        test_file_path, FileOptions(), &wfile, /*dbg=*/nullptr);
+    ASSERT_OK(s);
+    std::unique_ptr<WritableFileWriter> fwriter;
+    fwriter.reset(new WritableFileWriter(std::move(wfile), test_file_path,
+                                         FileOptions(), Env::Default()));
+    constexpr char buf[] = "test";
+    s = fwriter->Append(buf);
+    ASSERT_OK(s);
+  }
+  ASSERT_OK(Env::Default()->IsDirectory(test_file_path, &is_dir));
+  ASSERT_FALSE(is_dir);
+}
+
 }  // namespace ROCKSDB_NAMESPACE
 
 int main(int argc, char** argv) {

env/fs_posix.cc

@@ -877,6 +877,28 @@ class PosixFileSystem : public FileSystem {
     return IOStatus::OK();
   }
 
+  IOStatus IsDirectory(const std::string& path, const IOOptions& /*opts*/,
+                       bool* is_dir, IODebugContext* /*dbg*/) override {
+    // First open
+    int fd = -1;
+    int flags = cloexec_flags(O_RDONLY, nullptr);
+    {
+      IOSTATS_TIMER_GUARD(open_nanos);
+      fd = open(path.c_str(), flags);
+    }
+    if (fd < 0) {
+      return IOError("While open for IsDirectory()", path, errno);
+    }
+    struct stat sbuf;
+    if (fstat(fd, &sbuf) < 0) {
+      return IOError("While doing stat for IsDirectory()", path, errno);
+    }
+    if (nullptr != is_dir) {
+      *is_dir = S_ISDIR(sbuf.st_mode);
+    }
+    return IOStatus::OK();
+  }
+
   FileOptions OptimizeForLogWrite(const FileOptions& file_options,
                                  const DBOptions& db_options) const override {
     FileOptions optimized = file_options;

hdfs/env_hdfs.h

@@ -101,6 +101,8 @@ class HdfsEnv : public Env {
   Status NewLogger(const std::string& fname,
                    std::shared_ptr<Logger>* result) override;
 
+  Status IsDirectory(const std::string& path, bool* is_dir) override;
+
   void Schedule(void (*function)(void* arg), void* arg, Priority pri = LOW,
                 void* tag = nullptr,
                 void (*unschedFunction)(void* arg) = 0) override {
@@ -329,6 +331,10 @@ class HdfsEnv : public Env {
     return notsup;
   }
 
+  Status IsDirectory(const std::string& /*path*/, bool* /*is_dir*/) override {
+    return notsup;
+  }
+
   virtual void Schedule(void (* /*function*/)(void* arg), void* /*arg*/,
                         Priority /*pri*/ = LOW, void* /*tag*/ = nullptr,
                         void (* /*unschedFunction*/)(void* arg) = 0) override {}

include/rocksdb/env.h

@@ -227,7 +227,7 @@ class Env {
   virtual Status ReopenWritableFile(const std::string& /*fname*/,
                                     std::unique_ptr<WritableFile>* /*result*/,
                                     const EnvOptions& /*options*/) {
-    return Status::NotSupported();
+    return Status::NotSupported("Env::ReopenWritableFile() not supported.");
   }
 
   // Reuse an existing file by renaming it and opening it as writable.
@@ -461,7 +461,7 @@ class Env {
   virtual int GetBackgroundThreads(Priority pri = LOW) = 0;
 
   virtual Status SetAllowNonOwnerAccess(bool /*allow_non_owner_access*/) {
-    return Status::NotSupported("Not supported.");
+    return Status::NotSupported("Env::SetAllowNonOwnerAccess() not supported.");
   }
 
   // Enlarge number of background worker threads of a specific thread pool
@@ -518,7 +518,7 @@ class Env {
 
   // Returns the status of all threads that belong to the current Env.
   virtual Status GetThreadList(std::vector<ThreadStatus>* /*thread_list*/) {
-    return Status::NotSupported("Not supported.");
+    return Status::NotSupported("Env::GetThreadList() not supported.");
   }
 
   // Returns the pointer to ThreadStatusUpdater.  This function will be
@@ -537,7 +537,12 @@ class Env {
   // Get the amount of free disk space
   virtual Status GetFreeSpace(const std::string& /*path*/,
                               uint64_t* /*diskfree*/) {
-    return Status::NotSupported();
+    return Status::NotSupported("Env::GetFreeSpace() not supported.");
+  }
+
+  // Check whether the specified path is a directory
+  virtual Status IsDirectory(const std::string& /*path*/, bool* /*is_dir*/) {
+    return Status::NotSupported("Env::IsDirectory() not supported.");
   }
 
   virtual void SanitizeEnvOptions(EnvOptions* /*env_opts*/) const {}
@@ -599,14 +604,16 @@ class SequentialFile {
   // of this file. If the length is 0, then it refers to the end of file.
   // If the system is not caching the file contents, then this is a noop.
   virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
-    return Status::NotSupported("InvalidateCache not supported.");
+    return Status::NotSupported(
+        "SequentialFile::InvalidateCache not supported.");
   }
 
   // Positioned Read for direct I/O
   // If Direct I/O enabled, offset, n, and scratch should be properly aligned
   virtual Status PositionedRead(uint64_t /*offset*/, size_t /*n*/,
                                 Slice* /*result*/, char* /*scratch*/) {
-    return Status::NotSupported();
+    return Status::NotSupported(
+        "SequentialFile::PositionedRead() not supported.");
   }
 
   // If you're adding methods here, remember to add them to
@@ -709,7 +716,8 @@ class RandomAccessFile {
   // of this file. If the length is 0, then it refers to the end of file.
   // If the system is not caching the file contents, then this is a noop.
   virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
-    return Status::NotSupported("InvalidateCache not supported.");
+    return Status::NotSupported(
+        "RandomAccessFile::InvalidateCache not supported.");
   }
 
   // If you're adding methods here, remember to add them to
@@ -767,7 +775,8 @@ class WritableFile {
   // required is queried via GetRequiredBufferAlignment()
   virtual Status PositionedAppend(const Slice& /* data */,
                                   uint64_t /* offset */) {
-    return Status::NotSupported();
+    return Status::NotSupported(
+        "WritableFile::PositionedAppend() not supported.");
   }
 
   // Truncate is necessary to trim the file to the correct size
@@ -842,7 +851,7 @@ class WritableFile {
   // If the system is not caching the file contents, then this is a noop.
   // This call has no effect on dirty pages in the cache.
   virtual Status InvalidateCache(size_t /*offset*/, size_t /*length*/) {
-    return Status::NotSupported("InvalidateCache not supported.");
+    return Status::NotSupported("WritableFile::InvalidateCache not supported.");
   }
 
   // Sync a file range with disk.
@@ -1279,6 +1288,10 @@ class EnvWrapper : public Env {
 
   Status UnlockFile(FileLock* l) override { return target_->UnlockFile(l); }
 
+  Status IsDirectory(const std::string& path, bool* is_dir) override {
+    return target_->IsDirectory(path, is_dir);
+  }
+
   Status LoadLibrary(const std::string& lib_name,
                      const std::string& search_path,
                      std::shared_ptr<DynamicLibrary>* result) override {

include/rocksdb/file_system.h

@@ -522,6 +522,10 @@ class FileSystem {
     return IOStatus::NotSupported();
   }
 
+  virtual IOStatus IsDirectory(const std::string& /*path*/,
+                               const IOOptions& options, bool* is_dir,
+                               IODebugContext* /*dgb*/) = 0;
+
   // If you're adding methods here, remember to add them to EnvWrapper too.
 
  private:
@@ -1193,6 +1197,10 @@ class FileSystemWrapper : public FileSystem {
                         uint64_t* diskfree, IODebugContext* dbg) override {
     return target_->GetFreeSpace(path, options, diskfree, dbg);
   }
+  IOStatus IsDirectory(const std::string& path, const IOOptions& options,
+                       bool* is_dir, IODebugContext* dbg) override {
+    return target_->IsDirectory(path, options, is_dir, dbg);
+  }
 
  private:
   std::shared_ptr<FileSystem> target_;

port/win/env_win.cc

@@ -955,6 +955,14 @@ Status WinEnvIO::NewLogger(const std::string& fname,
   return s;
 }
 
+Status WinEnvIO::IsDirectory(const std::string& path, bool* is_dir) {
+  BOOL ret = RX_PathIsDirectory(RX_FN(path).c_str());
+  if (is_dir) {
+    *is_dir = ret ? true : false;
+  }
+  return Status::OK();
+}
+
 uint64_t WinEnvIO::NowMicros() {
 
   if (GetSystemTimePreciseAsFileTime_ != NULL) {
@@ -1433,6 +1441,10 @@ Status WinEnv::NewLogger(const std::string& fname,
   return winenv_io_.NewLogger(fname, result);
 }
 
+Status WinEnv::IsDirectory(const std::string& path, bool* is_dir) {
+  return winenv_io_.IsDirectory(path, is_dir);
+}
+
 uint64_t WinEnv::NowMicros() {
   return winenv_io_.NowMicros();
 }

port/win/env_win.h

@@ -155,6 +155,8 @@ public:
   virtual Status NewLogger(const std::string& fname,
                            std::shared_ptr<Logger>* result);
 
+  virtual Status IsDirectory(const std::string& path, bool* is_dir);
+
   virtual uint64_t NowMicros();
 
   virtual uint64_t NowNanos();
@@ -287,6 +289,8 @@ public:
   Status NewLogger(const std::string& fname,
                    std::shared_ptr<Logger>* result) override;
 
+  Status IsDirectory(const std::string& path, bool* is_dir) override;
+
   uint64_t NowMicros() override;
 
   uint64_t NowNanos() override;

port/win/port_win.h

@@ -365,6 +365,7 @@ extern void SetCpuPriority(ThreadId id, CpuPriority priority);
 #define RX_PathIsRelative PathIsRelativeW
 #define RX_GetCurrentDirectory GetCurrentDirectoryW
 #define RX_GetDiskFreeSpaceEx GetDiskFreeSpaceExW
+#define RX_PathIsDirectory PathIsDirectoryW
 
 #else
 
@@ -389,6 +390,7 @@ extern void SetCpuPriority(ThreadId id, CpuPriority priority);
 #define RX_PathIsRelative PathIsRelativeA
 #define RX_GetCurrentDirectory GetCurrentDirectoryA
 #define RX_GetDiskFreeSpaceEx GetDiskFreeSpaceExA
+#define RX_PathIsDirectory PathIsDirectoryA
 
 #endif