[VFS] Use original path when falling back to external FS

This is a follow up to 0be9ca7c0f9a733f846bb6bc4e8e36d46b518162 to make
paths in the case of falling back to the external file system use the
original format, preserving relative paths, and allow the external
filesystem to canonicalize them if needed.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D109128

1 files changed, 108 insertions, 0 deletions

diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index ca35b5e..be32971 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -1627,6 +1627,114 @@ TEST_F(VFSFromYAMLTest, RemappedDirectoryOverlayNoFallthrough) {
   EXPECT_EQ(0, NumDiagnostics);
 }
 
+TEST_F(VFSFromYAMLTest, ReturnsRequestedPathVFSMiss) {
+  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> BaseFS(
+      new vfs::InMemoryFileSystem);
+  BaseFS->addFile("//root/foo/a", 0,
+                  MemoryBuffer::getMemBuffer("contents of a"));
+  ASSERT_FALSE(BaseFS->setCurrentWorkingDirectory("//root/foo"));
+  auto RemappedFS = vfs::RedirectingFileSystem::create(
+      {}, /*UseExternalNames=*/false, *BaseFS);
+
+  auto OpenedF = RemappedFS->openFileForRead("a");
+  ASSERT_FALSE(OpenedF.getError());
+  llvm::ErrorOr<std::string> Name = (*OpenedF)->getName();
+  ASSERT_FALSE(Name.getError());
+  EXPECT_EQ("a", Name.get());
+
+  auto OpenedS = (*OpenedF)->status();
+  ASSERT_FALSE(OpenedS.getError());
+  EXPECT_EQ("a", OpenedS->getName());
+  EXPECT_FALSE(OpenedS->IsVFSMapped);
+
+  auto DirectS = RemappedFS->status("a");
+  ASSERT_FALSE(DirectS.getError());
+  EXPECT_EQ("a", DirectS->getName());
+  EXPECT_FALSE(DirectS->IsVFSMapped);
+
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, ReturnsExternalPathVFSHit) {
+  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> BaseFS(
+      new vfs::InMemoryFileSystem);
+  BaseFS->addFile("//root/foo/realname", 0,
+                  MemoryBuffer::getMemBuffer("contents of a"));
+  auto FS =
+      getFromYAMLString("{ 'use-external-names': true,\n"
+                        "  'roots': [\n"
+                        "{\n"
+                        "  'type': 'directory',\n"
+                        "  'name': '//root/foo',\n"
+                        "  'contents': [ {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'vfsname',\n"
+                        "                  'external-contents': 'realname'\n"
+                        "                }\n"
+                        "              ]\n"
+                        "}]}",
+                        BaseFS);
+  ASSERT_FALSE(FS->setCurrentWorkingDirectory("//root/foo"));
+
+  auto OpenedF = FS->openFileForRead("vfsname");
+  ASSERT_FALSE(OpenedF.getError());
+  llvm::ErrorOr<std::string> Name = (*OpenedF)->getName();
+  ASSERT_FALSE(Name.getError());
+  EXPECT_EQ("realname", Name.get());
+
+  auto OpenedS = (*OpenedF)->status();
+  ASSERT_FALSE(OpenedS.getError());
+  EXPECT_EQ("realname", OpenedS->getName());
+  EXPECT_TRUE(OpenedS->IsVFSMapped);
+
+  auto DirectS = FS->status("vfsname");
+  ASSERT_FALSE(DirectS.getError());
+  EXPECT_EQ("realname", DirectS->getName());
+  EXPECT_TRUE(DirectS->IsVFSMapped);
+
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, ReturnsInternalPathVFSHit) {
+  IntrusiveRefCntPtr<vfs::InMemoryFileSystem> BaseFS(
+      new vfs::InMemoryFileSystem);
+  BaseFS->addFile("//root/foo/realname", 0,
+                  MemoryBuffer::getMemBuffer("contents of a"));
+  auto FS =
+      getFromYAMLString("{ 'use-external-names': false,\n"
+                        "  'roots': [\n"
+                        "{\n"
+                        "  'type': 'directory',\n"
+                        "  'name': '//root/foo',\n"
+                        "  'contents': [ {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'vfsname',\n"
+                        "                  'external-contents': 'realname'\n"
+                        "                }\n"
+                        "              ]\n"
+                        "}]}",
+                        BaseFS);
+  ASSERT_FALSE(FS->setCurrentWorkingDirectory("//root/foo"));
+
+  auto OpenedF = FS->openFileForRead("vfsname");
+  ASSERT_FALSE(OpenedF.getError());
+  llvm::ErrorOr<std::string> Name = (*OpenedF)->getName();
+  ASSERT_FALSE(Name.getError());
+  EXPECT_EQ("vfsname", Name.get());
+
+  auto OpenedS = (*OpenedF)->status();
+  ASSERT_FALSE(OpenedS.getError());
+  EXPECT_EQ("vfsname", OpenedS->getName());
+  EXPECT_TRUE(OpenedS->IsVFSMapped);
+
+  auto DirectS = FS->status("vfsname");
+  ASSERT_FALSE(DirectS.getError());
+  EXPECT_EQ("vfsname", DirectS->getName());
+  EXPECT_TRUE(DirectS->IsVFSMapped);
+
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
 TEST_F(VFSFromYAMLTest, CaseInsensitive) {
   IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
   Lower->addRegularFile("//root/foo/bar/a");