Improves Clang's virtual file handling.

This patch contains:

- making some of the existing comments more accurate in the presence
of virtual files/directories.

- renaming some private data members of FileManager to match their roles better.

- creating 'DirectorEntry's for the parent directories of virtual
files, such that we can tell whether two virtual files are from the
same directory.  This is useful for injecting virtual files whose
directories don't exist in the real file system.

- minor clean-ups and adding comments for class
FileManager::UniqueDirContainer and FileManager::UniqueFileContainer.

- adding statistics on virtual files to FileManager::PrintStats().

- adding unit tests to verify the existing and new behavior of FileManager.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125384 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 238 insertions, 1 deletions

diff --git a/unittests/FileManager/FileManagerTest.cpp b/unittests/FileManager/FileManagerTest.cpp
new file mode 100644
index 0000000000..a7d3df3125
--- /dev/null
+++ b/unittests/FileManager/FileManagerTest.cpp
@@ -0,0 +1,222 @@
+//===- unittests/FileManager/FileMangerTest.cpp ------ FileManger tests ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/FileSystemOptions.h"
+#include "clang/Basic/FileSystemStatCache.h"
+#include "clang/Basic/FileManager.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace clang;
+
+namespace {
+
+// Used to create a fake file system for running the tests with such
+// that the tests are not affected by the structure/contents of the
+// file system on the machine running the tests.
+class FakeStatCache : public FileSystemStatCache {
+private:
+  // Maps a file/directory path to its desired stat result.  Anything
+  // not in this map is considered to not exist in the file system.
+  llvm::StringMap<struct stat, llvm::BumpPtrAllocator> StatCalls;
+
+  void InjectFileOrDirectory(const char *Path, ino_t INode, bool IsFile) {
+    struct stat statBuf = {};
+    statBuf.st_dev = 1;
+#ifndef LLVM_ON_WIN32  // struct stat has no st_ino field on Windows.
+    statBuf.st_ino = INode;
+#endif
+    statBuf.st_mode = IsFile ? (0777 | S_IFREG)  // a regular file
+        : (0777 | S_IFDIR);  // a directory
+    StatCalls[Path] = statBuf;
+  }
+
+public:
+  // Inject a file with the given inode value to the fake file system.
+  void InjectFile(const char *Path, ino_t INode) {
+    InjectFileOrDirectory(Path, INode, /*IsFile=*/true);
+  }
+
+  // Inject a directory with the given inode value to the fake file system.
+  void InjectDirectory(const char *Path, ino_t INode) {
+    InjectFileOrDirectory(Path, INode, /*IsFile=*/false);
+  }
+
+  // Implement FileSystemStatCache::getStat().
+  virtual LookupResult getStat(const char *Path, struct stat &StatBuf,
+                               int *FileDescriptor) {
+    if (StatCalls.count(Path) != 0) {
+      StatBuf = StatCalls[Path];
+      return CacheExists;
+    }
+
+    return CacheMissing;  // This means the file/directory doesn't exist.
+  }
+};
+
+// The test fixture.
+class FileManagerTest : public ::testing::Test {
+ protected:
+  FileManagerTest() : manager(options) {
+  }
+
+  FileSystemOptions options;
+  FileManager manager;
+};
+
+// When a virtual file is added, its getDir() field is set correctly
+// (not NULL, correct name).
+TEST_F(FileManagerTest, getVirtualFileSetsTheDirFieldCorrectly) {
+  const FileEntry *file = manager.getVirtualFile("foo.cpp", 42, 0);
+  ASSERT_TRUE(file != NULL);
+
+  const DirectoryEntry *dir = file->getDir();
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ(".", dir->getName());
+
+  file = manager.getVirtualFile("x/y/z.cpp", 42, 0);
+  ASSERT_TRUE(file != NULL);
+
+  dir = file->getDir();
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ("x/y", dir->getName());
+}
+
+// Before any virtual file is added, no virtual directory exists.
+TEST_F(FileManagerTest, NoVirtualDirectoryExistsBeforeAVirtualFileIsAdded) {
+  // An empty FakeStatCache causes all stat calls made by the
+  // FileManager to report "file/directory doesn't exist".  This
+  // avoids the possibility of the result of this test being affected
+  // by what's in the real file system.
+  manager.addStatCache(new FakeStatCache);
+
+  EXPECT_EQ(NULL, manager.getDirectory("virtual/dir/foo"));
+  EXPECT_EQ(NULL, manager.getDirectory("virtual/dir"));
+  EXPECT_EQ(NULL, manager.getDirectory("virtual"));
+}
+
+// When a virtual file is added, all of its ancestors should be created.
+TEST_F(FileManagerTest, getVirtualFileCreatesDirectoryEntriesForAncestors) {
+  // Fake an empty real file system.
+  manager.addStatCache(new FakeStatCache);
+
+  manager.getVirtualFile("virtual/dir/bar.h", 100, 0);
+  EXPECT_EQ(NULL, manager.getDirectory("virtual/dir/foo"));
+
+  const DirectoryEntry *dir = manager.getDirectory("virtual/dir");
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ("virtual/dir", dir->getName());
+
+  dir = manager.getDirectory("virtual");
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ("virtual", dir->getName());
+}
+
+// getFile() returns non-NULL if a real file exists at the given path.
+TEST_F(FileManagerTest, getFileReturnsValidFileEntryForExistingRealFile) {
+  // Inject fake files into the file system.
+  FakeStatCache *statCache = new FakeStatCache;
+  statCache->InjectDirectory("/tmp", 42);
+  statCache->InjectFile("/tmp/test", 43);
+  manager.addStatCache(statCache);
+
+  const FileEntry *file = manager.getFile("/tmp/test");
+  ASSERT_TRUE(file != NULL);
+  EXPECT_STREQ("/tmp/test", file->getName());
+
+  const DirectoryEntry *dir = file->getDir();
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ("/tmp", dir->getName());
+}
+
+// getFile() returns non-NULL if a virtual file exists at the given path.
+TEST_F(FileManagerTest, getFileReturnsValidFileEntryForExistingVirtualFile) {
+  // Fake an empty real file system.
+  manager.addStatCache(new FakeStatCache);
+
+  manager.getVirtualFile("virtual/dir/bar.h", 100, 0);
+  const FileEntry *file = manager.getFile("virtual/dir/bar.h");
+  ASSERT_TRUE(file != NULL);
+  EXPECT_STREQ("virtual/dir/bar.h", file->getName());
+
+  const DirectoryEntry *dir = file->getDir();
+  ASSERT_TRUE(dir != NULL);
+  EXPECT_STREQ("virtual/dir", dir->getName());
+}
+
+// getFile() returns different FileEntries for different paths when
+// there's no aliasing.
+TEST_F(FileManagerTest, getFileReturnsDifferentFileEntriesForDifferentFiles) {
+  // Inject two fake files into the file system.  Different inodes
+  // mean the files are not symlinked together.
+  FakeStatCache *statCache = new FakeStatCache;
+  statCache->InjectDirectory(".", 41);
+  statCache->InjectFile("foo.cpp", 42);
+  statCache->InjectFile("bar.cpp", 43);
+  manager.addStatCache(statCache);
+
+  const FileEntry *fileFoo = manager.getFile("foo.cpp");
+  const FileEntry *fileBar = manager.getFile("bar.cpp");
+  ASSERT_TRUE(fileFoo != NULL);
+  ASSERT_TRUE(fileBar != NULL);
+  EXPECT_NE(fileFoo, fileBar);
+}
+
+// getFile() returns NULL if neither a real file nor a virtual file
+// exists at the given path.
+TEST_F(FileManagerTest, getFileReturnsNULLForNonexistentFile) {
+  // Inject a fake foo.cpp into the file system.
+  FakeStatCache *statCache = new FakeStatCache;
+  statCache->InjectDirectory(".", 41);
+  statCache->InjectFile("foo.cpp", 42);
+  manager.addStatCache(statCache);
+
+  // Create a virtual bar.cpp file.
+  manager.getVirtualFile("bar.cpp", 200, 0);
+
+  const FileEntry *file = manager.getFile("xyz.txt");
+  EXPECT_EQ(NULL, file);
+}
+
+// The following tests apply to Unix-like system only.
+
+#ifndef LLVM_ON_WIN32
+
+// getFile() returns the same FileEntry for real files that are aliases.
+TEST_F(FileManagerTest, getFileReturnsSameFileEntryForAliasedRealFiles) {
+  // Inject two real files with the same inode.
+  FakeStatCache *statCache = new FakeStatCache;
+  statCache->InjectDirectory("abc", 41);
+  statCache->InjectFile("abc/foo.cpp", 42);
+  statCache->InjectFile("abc/bar.cpp", 42);
+  manager.addStatCache(statCache);
+
+  EXPECT_EQ(manager.getFile("abc/foo.cpp"), manager.getFile("abc/bar.cpp"));
+}
+
+// getFile() returns the same FileEntry for virtual files that have
+// corresponding real files that are aliases.
+TEST_F(FileManagerTest, getFileReturnsSameFileEntryForAliasedVirtualFiles) {
+  // Inject two real files with the same inode.
+  FakeStatCache *statCache = new FakeStatCache;
+  statCache->InjectDirectory("abc", 41);
+  statCache->InjectFile("abc/foo.cpp", 42);
+  statCache->InjectFile("abc/bar.cpp", 42);
+  manager.addStatCache(statCache);
+
+  manager.getVirtualFile("abc/foo.cpp", 100, 0);
+  manager.getVirtualFile("abc/bar.cpp", 200, 0);
+
+  EXPECT_EQ(manager.getFile("abc/foo.cpp"), manager.getFile("abc/bar.cpp"));
+}
+
+#endif  // !LLVM_ON_WIN32
+
+} // anonymous namespace
diff --git a/unittests/FileManager/Makefile b/unittests/FileManager/Makefile
new file mode 100644
index 0000000000..3851aa4f59
--- /dev/null
+++ b/unittests/FileManager/Makefile
@@ -0,0 +1,15 @@
+##===- unittests/FileManager/Makefile ----------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+CLANG_LEVEL = ../..
+TESTNAME = FileManager
+LINK_COMPONENTS := core support mc
+USEDLIBS = clangBasic.a
+
+include $(CLANG_LEVEL)/unittests/Makefile
diff --git a/unittests/Makefile b/unittests/Makefile
index 685e397864..e8b4d55f3d 100644
--- a/unittests/Makefile
+++ b/unittests/Makefile
@@ -14,7 +14,7 @@ ifndef CLANG_LEVEL
 
 IS_UNITTEST_LEVEL := 1
 CLANG_LEVEL := ..
-PARALLEL_DIRS = Frontend
+PARALLEL_DIRS = FileManager Frontend
 
 endif  # CLANG_LEVEL