utils: expand AbsolutePathBase to provide some filesystem related methods via Boost

Summary:
These methods will be used in my later Windows fsck diff as it will need to scan disk state to find changes.

It is a bit unfortunate that we'll need to stick with boost for now. However this should be a fairly easy migration to `std::filesystem` once that is available.

Reviewed By: kmancini

Differential Revision: D27872828

fbshipit-source-id: f6b27a171026aeaaea3db9f17b8f43cfa25004e4

eden/fs/utils/PathFuncs.cpp

@@ -8,7 +8,6 @@
 #include "eden/fs/utils/PathFuncs.h"
 
 #include <boost/filesystem/operations.hpp>
-#include <boost/filesystem/path.hpp>
 
 #include <folly/Exception.h>
 #include <folly/logging/xlog.h>
@@ -273,29 +272,22 @@ void validatePathComponentLength(PathComponentPiece name) {
   }
 }
 
-namespace {
-boost::filesystem::path toBoostPath(AbsolutePathPiece path) {
-  auto piece = path.stringPiece();
-  return boost::filesystem::path(piece.begin(), piece.end());
-}
-} // namespace
-
 bool ensureDirectoryExists(AbsolutePathPiece path) {
-  return boost::filesystem::create_directories(toBoostPath(path));
+  return boost::filesystem::create_directories(path.as_boost());
 }
 
 bool removeRecursively(AbsolutePathPiece path) {
-  return boost::filesystem::remove_all(toBoostPath(path));
+  return boost::filesystem::remove_all(path.as_boost());
 }
 
 bool removeFileWithAbsolutePath(AbsolutePathPiece path) {
-  return boost::filesystem::remove(toBoostPath(path));
+  return boost::filesystem::remove(path.as_boost());
 }
 
 void renameWithAbsolutePath(
     AbsolutePathPiece srcPath,
     AbsolutePathPiece destPath) {
-  boost::filesystem::rename(toBoostPath(srcPath), toBoostPath(destPath));
+  boost::filesystem::rename(srcPath.as_boost(), destPath.as_boost());
 }
 
 AbsolutePath expandUser(

eden/fs/utils/PathFuncs.h

@@ -9,6 +9,8 @@
 
 #include "eden/fs/utils/Memory.h"
 
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/path.hpp>
 #include <boost/operators.hpp>
 
 #include <fmt/format.h>
@@ -1420,6 +1422,24 @@ class AbsolutePathBase : public ComposedPathBase<
   const char* c_str() const {
     return this->path_.c_str();
   }
+
+  // TODO: switch to `std::filesystem` once it is ready
+  boost::filesystem::path as_boost() const {
+    auto piece = this->stringPiece();
+    return boost::filesystem::path(piece.begin(), piece.end());
+  }
+
+  bool is_regular_file() const {
+    return boost::filesystem::is_regular_file(as_boost());
+  }
+
+  bool is_directory() const {
+    return boost::filesystem::is_directory(as_boost());
+  }
+
+  bool exists() const {
+    return boost::filesystem::exists(as_boost());
+  }
 };
 
 /**

eden/fs/utils/test/PathFuncsTest.cpp

@@ -1015,6 +1015,54 @@ TEST(PathFuncs, localDirCreateRemove) {
   ASSERT_FALSE(removeRecursively(topDir));
 }
 
+TEST(PathFuncs, exists) {
+  folly::test::TemporaryDirectory dir = makeTempDir();
+  string pathStr{dir.path().string()};
+  AbsolutePathPiece tmpDir{pathStr};
+
+  auto filePath = tmpDir + "test.txt"_relpath;
+  EXPECT_FALSE(filePath.exists());
+  writeFile(filePath, StringPiece("hello\nworld")).throwUnlessValue();
+  EXPECT_TRUE(filePath.exists());
+
+  auto directoryPath = tmpDir + "dir"_relpath;
+  EXPECT_FALSE(directoryPath.exists());
+  ensureDirectoryExists(directoryPath);
+  EXPECT_TRUE(directoryPath.exists());
+}
+
+TEST(PathFuns, isRegularFile) {
+  folly::test::TemporaryDirectory dir = makeTempDir();
+  string pathStr{dir.path().string()};
+  AbsolutePathPiece tmpDir{pathStr};
+
+  auto filePath = tmpDir + "test.txt"_relpath;
+  EXPECT_FALSE(filePath.is_regular_file());
+  writeFile(filePath, StringPiece("hello\nworld")).throwUnlessValue();
+  EXPECT_TRUE(filePath.is_regular_file());
+
+  auto directoryPath = tmpDir + "dir"_relpath;
+  EXPECT_FALSE(directoryPath.is_regular_file());
+  ensureDirectoryExists(directoryPath);
+  EXPECT_FALSE(directoryPath.is_regular_file());
+}
+
+TEST(PathFuncs, isDirectory) {
+  folly::test::TemporaryDirectory dir = makeTempDir();
+  string pathStr{dir.path().string()};
+  AbsolutePathPiece tmpDir{pathStr};
+
+  auto filePath = tmpDir + "test.txt"_relpath;
+  EXPECT_FALSE(filePath.is_directory());
+  writeFile(filePath, StringPiece("hello\nworld")).throwUnlessValue();
+  EXPECT_FALSE(filePath.is_directory());
+
+  auto directoryPath = tmpDir + "dir"_relpath;
+  EXPECT_FALSE(directoryPath.is_directory());
+  ensureDirectoryExists(directoryPath);
+  EXPECT_TRUE(directoryPath.is_directory());
+}
+
 TEST(PathFuncs, noThrow) {
   // if std::string is nothrow move constructible and assignable, the
   // path types should be as well.