[Lldb-commits] [PATCH] D77351: [lldb/Support] Treat empty FileSpec as an invalid file.

[Jonas Devlieghere via Phabricator via lldb-commits]

JDevlieghere created this revision.
JDevlieghere added reviewers: labath, teemperor.

LLDB relies on empty FileSpecs being invalid files, for example, they don't 
exists. Currently this assumption does not always hold during reproducer 
replay, because we pass the result of `GetPath` to the VFS. This is an empty 
string, which the VFS converts to an absolute directory by prepending the 
current working directory, before looking it up in the YAML mapping. This means 
that an empty FileSpec will exist when the current working directory does. This 
breaks at least one test (`TestAddDsymCommand.py`) when ran from replay.

This patch special cases empty FileSpecs and returns a sensible result before 
calling GetPath and forwarding the call.


Repository:
  rLLDB LLDB

https://reviews.llvm.org/D77351

Files:
  lldb/source/Host/common/FileSystem.cpp
  lldb/unittests/Host/FileSystemTest.cpp


Index: lldb/unittests/Host/FileSystemTest.cpp
===================================================================
--- lldb/unittests/Host/FileSystemTest.cpp
+++ lldb/unittests/Host/FileSystemTest.cpp
@@ -303,3 +303,29 @@
   EXPECT_EQ(code.value(), ENOENT);
 }
 
+TEST(FileSystemTest, EmptyTest) {
+  FileSpec spec;
+  FileSystem fs;
+
+  {
+    std::error_code ec;
+    fs.DirBegin(spec, ec);
+    EXPECT_EQ(ec.category(), std::system_category());
+    EXPECT_EQ(ec.value(), ENOENT);
+  }
+
+  {
+    llvm::ErrorOr<vfs::Status> status = fs.GetStatus(spec);
+    ASSERT_FALSE(status);
+    EXPECT_EQ(status.getError().category(), std::system_category());
+    EXPECT_EQ(status.getError().value(), ENOENT);
+  }
+
+  EXPECT_EQ(sys::TimePoint<>(), fs.GetModificationTime(spec));
+  EXPECT_EQ(static_cast<uint64_t>(0), fs.GetByteSize(spec));
+  EXPECT_EQ(llvm::sys::fs::perms::perms_not_known, fs.GetPermissions(spec));
+  EXPECT_FALSE(fs.Exists(spec));
+  EXPECT_FALSE(fs.Readable(spec));
+  EXPECT_FALSE(fs.IsDirectory(spec));
+  EXPECT_FALSE(fs.IsLocal(spec));
+}
Index: lldb/source/Host/common/FileSystem.cpp
===================================================================
--- lldb/source/Host/common/FileSystem.cpp
+++ lldb/source/Host/common/FileSystem.cpp
@@ -87,6 +87,11 @@
 
 vfs::directory_iterator FileSystem::DirBegin(const FileSpec &file_spec,
                                              std::error_code &ec) {
+  if (!file_spec) {
+    ec = std::error_code(static_cast<int>(errc::no_such_file_or_directory),
+                         std::system_category());
+    return {};
+  }
   return DirBegin(file_spec.GetPath(), ec);
 }
 
@@ -97,6 +102,9 @@
 
 llvm::ErrorOr<vfs::Status>
 FileSystem::GetStatus(const FileSpec &file_spec) const {
+  if (!file_spec)
+    return std::error_code(static_cast<int>(errc::no_such_file_or_directory),
+                           std::system_category());
   return GetStatus(file_spec.GetPath());
 }
 
@@ -106,6 +114,8 @@
 
 sys::TimePoint<>
 FileSystem::GetModificationTime(const FileSpec &file_spec) const {
+  if (!file_spec)
+    return sys::TimePoint<>();
   return GetModificationTime(file_spec.GetPath());
 }
 
@@ -117,6 +127,8 @@
 }
 
 uint64_t FileSystem::GetByteSize(const FileSpec &file_spec) const {
+  if (!file_spec)
+    return 0;
   return GetByteSize(file_spec.GetPath());
 }
 
@@ -133,6 +145,8 @@
 
 uint32_t FileSystem::GetPermissions(const FileSpec &file_spec,
                                     std::error_code &ec) const {
+  if (!file_spec)
+    return sys::fs::perms::perms_not_known;
   return GetPermissions(file_spec.GetPath(), ec);
 }
 
@@ -154,7 +168,7 @@
 bool FileSystem::Exists(const Twine &path) const { return m_fs->exists(path); }
 
 bool FileSystem::Exists(const FileSpec &file_spec) const {
-  return Exists(file_spec.GetPath());
+  return file_spec && Exists(file_spec.GetPath());
 }
 
 bool FileSystem::Readable(const Twine &path) const {
@@ -162,7 +176,7 @@
 }
 
 bool FileSystem::Readable(const FileSpec &file_spec) const {
-  return Readable(file_spec.GetPath());
+  return file_spec && Readable(file_spec.GetPath());
 }
 
 bool FileSystem::IsDirectory(const Twine &path) const {
@@ -173,7 +187,7 @@
 }
 
 bool FileSystem::IsDirectory(const FileSpec &file_spec) const {
-  return IsDirectory(file_spec.GetPath());
+  return file_spec && IsDirectory(file_spec.GetPath());
 }
 
 bool FileSystem::IsLocal(const Twine &path) const {
@@ -183,7 +197,7 @@
 }
 
 bool FileSystem::IsLocal(const FileSpec &file_spec) const {
-  return IsLocal(file_spec.GetPath());
+  return file_spec && IsLocal(file_spec.GetPath());
 }
 
 void FileSystem::EnumerateDirectory(Twine path, bool find_directories,
@@ -261,6 +275,9 @@
 }
 
 void FileSystem::Resolve(FileSpec &file_spec) {
+  if (!file_spec)
+    return;
+
   // Extract path from the FileSpec.
   SmallString<128> path;
   file_spec.GetPath(path);

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