1 files changed, 182 insertions, 0 deletions

diff --git a/source/Utility/FileCollector.cpp b/source/Utility/FileCollector.cpp
new file mode 100644
index 000000000000..ed9359192205
--- /dev/null
+++ b/source/Utility/FileCollector.cpp
@@ -0,0 +1,182 @@
+//===-- FileCollector.cpp ---------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Utility/FileCollector.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
+
+using namespace lldb_private;
+using namespace llvm;
+
+static bool IsCaseSensitivePath(StringRef path) {
+  SmallString<256> tmp_dest = path, upper_dest, real_dest;
+
+  // Remove component traversals, links, etc.
+  if (!sys::fs::real_path(path, tmp_dest))
+    return true; // Current default value in vfs.yaml
+  path = tmp_dest;
+
+  // Change path to all upper case and ask for its real path, if the latter
+  // exists and is equal to path, it's not case sensitive. Default to case
+  // sensitive in the absence of real_path, since this is the YAMLVFSWriter
+  // default.
+  upper_dest = path.upper();
+  if (sys::fs::real_path(upper_dest, real_dest) && path.equals(real_dest))
+    return false;
+  return true;
+}
+
+FileCollector::FileCollector(const FileSpec &root, const FileSpec &overlay_root)
+    : m_root(root), m_overlay_root(overlay_root) {
+  sys::fs::create_directories(m_root.GetPath(), true);
+}
+
+bool FileCollector::GetRealPath(StringRef src_path,
+                                SmallVectorImpl<char> &result) {
+  SmallString<256> real_path;
+  StringRef FileName = sys::path::filename(src_path);
+  std::string directory = sys::path::parent_path(src_path).str();
+  auto dir_with_symlink = m_symlink_map.find(directory);
+
+  // Use real_path to fix any symbolic link component present in a path.
+  // Computing the real path is expensive, cache the search through the
+  // parent path directory.
+  if (dir_with_symlink == m_symlink_map.end()) {
+    auto ec = sys::fs::real_path(directory, real_path);
+    if (ec)
+      return false;
+    m_symlink_map[directory] = real_path.str();
+  } else {
+    real_path = dir_with_symlink->second;
+  }
+
+  sys::path::append(real_path, FileName);
+  result.swap(real_path);
+  return true;
+}
+
+void FileCollector::AddFile(const Twine &file) {
+  std::lock_guard<std::mutex> lock(m_mutex);
+  std::string file_str = file.str();
+  if (MarkAsSeen(file_str))
+    AddFileImpl(file_str);
+}
+
+void FileCollector::AddFileImpl(StringRef src_path) {
+  std::string root = m_root.GetPath();
+
+  // We need an absolute src path to append to the root.
+  SmallString<256> absolute_src = src_path;
+  sys::fs::make_absolute(absolute_src);
+
+  // Canonicalize src to a native path to avoid mixed separator styles.
+  sys::path::native(absolute_src);
+
+  // Remove redundant leading "./" pieces and consecutive separators.
+  absolute_src = sys::path::remove_leading_dotslash(absolute_src);
+
+  // Canonicalize the source path by removing "..", "." components.
+  SmallString<256> virtual_path = absolute_src;
+  sys::path::remove_dots(virtual_path, /*remove_dot_dot=*/true);
+
+  // If a ".." component is present after a symlink component, remove_dots may
+  // lead to the wrong real destination path. Let the source be canonicalized
+  // like that but make sure we always use the real path for the destination.
+  SmallString<256> copy_from;
+  if (!GetRealPath(absolute_src, copy_from))
+    copy_from = virtual_path;
+
+  SmallString<256> dst_path = StringRef(root);
+  sys::path::append(dst_path, sys::path::relative_path(copy_from));
+
+  // Always map a canonical src path to its real path into the YAML, by doing
+  // this we map different virtual src paths to the same entry in the VFS
+  // overlay, which is a way to emulate symlink inside the VFS; this is also
+  // needed for correctness, not doing that can lead to module redefinition
+  // errors.
+  AddFileToMapping(virtual_path, dst_path);
+}
+
+/// Set the access and modification time for the given file from the given
+/// status object.
+static std::error_code
+CopyAccessAndModificationTime(StringRef filename,
+                              const sys::fs::file_status &stat) {
+  int fd;
+
+  if (auto ec =
+          sys::fs::openFileForWrite(filename, fd, sys::fs::CD_OpenExisting))
+    return ec;
+
+  if (auto ec = sys::fs::setLastAccessAndModificationTime(
+          fd, stat.getLastAccessedTime(), stat.getLastModificationTime()))
+    return ec;
+
+  if (auto ec = sys::Process::SafelyCloseFileDescriptor(fd))
+    return ec;
+
+  return {};
+}
+
+std::error_code FileCollector::CopyFiles(bool stop_on_error) {
+  for (auto &entry : m_vfs_writer.getMappings()) {
+    // Create directory tree.
+    if (std::error_code ec =
+            sys::fs::create_directories(sys::path::parent_path(entry.RPath),
+                                        /*IgnoreExisting=*/true)) {
+      if (stop_on_error)
+        return ec;
+    }
+
+    // Copy file over.
+    if (std::error_code ec = sys::fs::copy_file(entry.VPath, entry.RPath)) {
+      if (stop_on_error)
+        return ec;
+    }
+
+    // Copy over permissions.
+    if (auto perms = sys::fs::getPermissions(entry.VPath)) {
+      if (std::error_code ec = sys::fs::setPermissions(entry.RPath, *perms)) {
+        if (stop_on_error)
+          return ec;
+      }
+    }
+
+    // Copy over modification time.
+    sys::fs::file_status stat;
+    if (std::error_code ec = sys::fs::status(entry.VPath, stat)) {
+      if (stop_on_error)
+        return ec;
+      continue;
+    }
+    CopyAccessAndModificationTime(entry.RPath, stat);
+  }
+  return {};
+}
+
+std::error_code FileCollector::WriteMapping(const FileSpec &mapping_file) {
+  std::lock_guard<std::mutex> lock(m_mutex);
+
+  std::string root = m_overlay_root.GetPath();
+
+  m_vfs_writer.setOverlayDir(root);
+  m_vfs_writer.setCaseSensitivity(IsCaseSensitivePath(root));
+  m_vfs_writer.setUseExternalNames(false);
+
+  std::error_code ec;
+  raw_fd_ostream os(mapping_file.GetPath(), ec, sys::fs::F_Text);
+  if (ec)
+    return ec;
+
+  m_vfs_writer.write(os);
+
+  return {};
+}