[VFS] Add print/dump to the whole FileSystem hierarchy

For now most are implemented by printing out the name of the filesystem,
but this can be expanded in the future. Only `OverlayFileSystem` and
`RedirectingFileSystem` are properly implemented in this patch.
  - `OverlayFileSystem`: Prints each filesystem in the order that any
    operations are actually run on them. Optionally prints recursively.
  - `RedirectingFileSystem`: Prints out all mappings, as well as the
    `ExternalFS`. Most of this was already implemented other than the
    handling for the `DirectoryRemap` case and to actually print out the
    mapping.

Each FS should implement `printImpl` rather than `print`, where the
latter just fowards to the former. This is to avoid spreading the
default arguments through to the subclasses (where we may miss updating
in the future).

Differential Revision: https://reviews.llvm.org/D121421

1 files changed, 126 insertions, 0 deletions

diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index 657fc0a..1eb7fe6 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -171,6 +171,25 @@ public:
                   sys::fs::file_type::symlink_file, sys::fs::all_all);
     addEntry(Path, S);
   }
+
+protected:
+  void printImpl(raw_ostream &OS, PrintType Type,
+                 unsigned IndentLevel) const override {
+    printIndent(OS, IndentLevel);
+    OS << "DummyFileSystem (";
+    switch (Type) {
+    case vfs::FileSystem::PrintType::Summary:
+      OS << "Summary";
+      break;
+    case vfs::FileSystem::PrintType::Contents:
+      OS << "Contents";
+      break;
+    case vfs::FileSystem::PrintType::RecursiveContents:
+      OS << "RecursiveContents";
+      break;
+    }
+    OS << ")\n";
+  }
 };
 
 class ErrorDummyFileSystem : public DummyFileSystem {
@@ -848,6 +867,36 @@ TEST(VirtualFileSystemTest, HiddenInIteration) {
   }
 }
 
+TEST(OverlayFileSystemTest, PrintOutput) {
+  auto Dummy = makeIntrusiveRefCnt<DummyFileSystem>();
+  auto Overlay1 = makeIntrusiveRefCnt<vfs::OverlayFileSystem>(Dummy);
+  Overlay1->pushOverlay(Dummy);
+  auto Overlay2 = makeIntrusiveRefCnt<vfs::OverlayFileSystem>(Overlay1);
+  Overlay2->pushOverlay(Dummy);
+
+  SmallString<0> Output;
+  raw_svector_ostream OuputStream{Output};
+
+  Overlay2->print(OuputStream, vfs::FileSystem::PrintType::Summary);
+  ASSERT_EQ("OverlayFileSystem\n", Output);
+
+  Output.clear();
+  Overlay2->print(OuputStream, vfs::FileSystem::PrintType::Contents);
+  ASSERT_EQ("OverlayFileSystem\n"
+            "  DummyFileSystem (Summary)\n"
+            "  OverlayFileSystem\n",
+            Output);
+
+  Output.clear();
+  Overlay2->print(OuputStream, vfs::FileSystem::PrintType::RecursiveContents);
+  ASSERT_EQ("OverlayFileSystem\n"
+            "  DummyFileSystem (RecursiveContents)\n"
+            "  OverlayFileSystem\n"
+            "    DummyFileSystem (RecursiveContents)\n"
+            "    DummyFileSystem (RecursiveContents)\n",
+            Output);
+}
+
 TEST(ProxyFileSystemTest, Basic) {
   IntrusiveRefCntPtr<vfs::InMemoryFileSystem> Base(
       new vfs::InMemoryFileSystem());
@@ -2928,3 +2977,80 @@ TEST(VFSFromRemappedFilesTest, LastMappingWins) {
   EXPECT_EQ("contents of c", (*BufferKeepA)->getBuffer());
   EXPECT_EQ("contents of c", (*BufferExternalA)->getBuffer());
 }
+
+TEST(RedirectingFileSystemTest, PrintOutput) {
+  auto Buffer =
+      MemoryBuffer::getMemBuffer("{\n"
+                                 "  'version': 0,\n"
+                                 "  'roots': [\n"
+                                 "    {\n"
+                                 "      'type': 'directory-remap',\n"
+                                 "      'name': '/dremap',\n"
+                                 "      'external-contents': '/a',\n"
+                                 "    },"
+                                 "    {\n"
+                                 "      'type': 'directory',\n"
+                                 "      'name': '/vdir',\n"
+                                 "      'contents': ["
+                                 "        {\n"
+                                 "          'type': 'directory-remap',\n"
+                                 "          'name': 'dremap',\n"
+                                 "          'external-contents': '/b'\n"
+                                 "          'use-external-name': 'true'\n"
+                                 "        },\n"
+                                 "        {\n"
+                                 "          'type': 'file',\n"
+                                 "          'name': 'vfile',\n"
+                                 "          'external-contents': '/c'\n"
+                                 "          'use-external-name': 'false'\n"
+                                 "        }]\n"
+                                 "    }]\n"
+                                 "}");
+
+  auto Dummy = makeIntrusiveRefCnt<DummyFileSystem>();
+  auto Redirecting = vfs::RedirectingFileSystem::create(
+      std::move(Buffer), nullptr, "", nullptr, Dummy);
+
+  SmallString<0> Output;
+  raw_svector_ostream OuputStream{Output};
+
+  Redirecting->print(OuputStream, vfs::FileSystem::PrintType::Summary);
+  ASSERT_EQ("RedirectingFileSystem (UseExternalNames: true)\n", Output);
+
+  Output.clear();
+  Redirecting->print(OuputStream, vfs::FileSystem::PrintType::Contents);
+  ASSERT_EQ("RedirectingFileSystem (UseExternalNames: true)\n"
+            "'/'\n"
+            "  'dremap' -> '/a'\n"
+            "  'vdir'\n"
+            "    'dremap' -> '/b' (UseExternalName: true)\n"
+            "    'vfile' -> '/c' (UseExternalName: false)\n"
+            "ExternalFS:\n"
+            "  DummyFileSystem (Summary)\n",
+            Output);
+
+  Output.clear();
+  Redirecting->print(OuputStream, vfs::FileSystem::PrintType::Contents, 1);
+  ASSERT_EQ("  RedirectingFileSystem (UseExternalNames: true)\n"
+            "  '/'\n"
+            "    'dremap' -> '/a'\n"
+            "    'vdir'\n"
+            "      'dremap' -> '/b' (UseExternalName: true)\n"
+            "      'vfile' -> '/c' (UseExternalName: false)\n"
+            "  ExternalFS:\n"
+            "    DummyFileSystem (Summary)\n",
+            Output);
+
+  Output.clear();
+  Redirecting->print(OuputStream,
+                     vfs::FileSystem::PrintType::RecursiveContents);
+  ASSERT_EQ("RedirectingFileSystem (UseExternalNames: true)\n"
+            "'/'\n"
+            "  'dremap' -> '/a'\n"
+            "  'vdir'\n"
+            "    'dremap' -> '/b' (UseExternalName: true)\n"
+            "    'vfile' -> '/c' (UseExternalName: false)\n"
+            "ExternalFS:\n"
+            "  DummyFileSystem (RecursiveContents)\n",
+            Output);
+}