Move the :install_paths library to //toolchain/base (#6457)

Previously this was kept in `//toolchain/install` so it would be near to the code that actually defines the installation layout. However, that creates somewhat unfortunate dependency cycles between `//toolchain/install` and other directories. Exacerbating this, a subsequent PR is likely to add dependencies on it from `//toolchain/base` itself that suggests that is the correct layering. This PR just moves the code mechanically with as few other edits as possible.
2026-10-05 22:02:55 +01:00 · 2025-12-03 17:14:34 +00:00
parent 4ddff65e8e
commit 5d0d443c98
31 changed files with 108 additions and 108 deletions
@@ -0,0 +1,252 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "toolchain/base/install_paths.h"
+
+#include <filesystem>
+#include <memory>
+#include <string>
+
+#include "clang/Basic/Version.h"
+#include "common/check.h"
+#include "common/filesystem.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
+#include "tools/cpp/runfiles/runfiles.h"
+
+namespace Carbon {
+
+// The location within our Bazel output tree of the prefix_root.
+static constexpr llvm::StringLiteral PrefixRoot =
+    "carbon/toolchain/install/prefix_root/";
+
+// Path within an install prefix for our marker of a valid install.
+static constexpr llvm::StringLiteral MarkerPath =
+    "lib/carbon/carbon_install.txt";
+
+auto InstallPaths::MakeExeRelative(llvm::StringRef exe_path) -> InstallPaths {
+  InstallPaths paths;
+
+  // Double check the exe was present.
+  auto exe_access_result = Filesystem::Cwd().Access(exe_path.str());
+  if (!exe_access_result.ok()) {
+    paths.SetError(llvm::Twine("Failed to test for access executable: ") +
+                   exe_access_result.error().ToString());
+    return paths;
+  } else if (!*exe_access_result) {
+    paths.SetError(llvm::Twine("Unable to access executable: ") + exe_path);
+    return paths;
+  }
+
+  return MakeFromFile(exe_path.str());
+}
+
+auto InstallPaths::MakeForBazelRunfiles(llvm::StringRef exe_path)
+    -> InstallPaths {
+  using bazel::tools::cpp::runfiles::Runfiles;
+  std::string runtimes_error;
+  std::unique_ptr<Runfiles> runfiles(
+      Runfiles::Create(exe_path.str(), &runtimes_error));
+  CARBON_CHECK(runfiles != nullptr, "Failed to find runtimes tree: {0}",
+               runtimes_error);
+
+  std::string relative_marker_path = (PrefixRoot.str() + MarkerPath).str();
+  std::filesystem::path runtimes_marker_path =
+      runfiles->Rlocation(relative_marker_path);
+
+  // Start from the marker, remove that filename, and walk up to find the
+  // install prefix.
+  return MakeFromFile(std::move(runtimes_marker_path));
+}
+
+auto InstallPaths::Make(llvm::StringRef install_prefix) -> InstallPaths {
+  InstallPaths paths(install_prefix.str());
+  auto open_result = Filesystem::Cwd().OpenDir(paths.prefix_);
+  if (!open_result.ok()) {
+    paths.SetError(open_result.error().ToString());
+  } else {
+    paths.prefix_dir_ = *std::move(open_result);
+    paths.CheckMarkerFile();
+  }
+  return paths;
+}
+
+auto InstallPaths::ReadPreludeManifest() const
+    -> ErrorOr<llvm::SmallVector<std::string>> {
+  return ReadManifest(core_package(), "prelude_manifest.txt");
+}
+
+auto InstallPaths::ReadClangHeadersManifest() const
+    -> ErrorOr<llvm::SmallVector<std::string>> {
+  return ReadManifest(prefix_ / "..", "clang_headers_manifest.txt");
+}
+
+auto InstallPaths::ReadManifest(std::filesystem::path manifest_path,
+                                std::filesystem::path manifest_file) const
+    -> ErrorOr<llvm::SmallVector<std::string>> {
+  // This is structured to avoid a vector copy on success.
+  ErrorOr<llvm::SmallVector<std::string>> result =
+      llvm::SmallVector<std::string>();
+
+  // TODO: It would be nice to adjust the manifests to be within the install
+  // prefix and use that open directory to access the manifest. Also to update
+  // callers to be able to use the relative paths via an open directory rather
+  // than having to form absolute paths for all the entries.
+  auto read_result =
+      Filesystem::Cwd().ReadFileToString(manifest_path / manifest_file);
+  if (!read_result.ok()) {
+    result = ErrorBuilder()
+             << "Loading manifest `" << (manifest_path / manifest_file)
+             << "`: " << read_result.error();
+    return result;
+  }
+
+  // The manifest should have one file per line.
+  llvm::StringRef buffer = *read_result;
+  while (true) {
+    auto [token, remainder] = llvm::getToken(buffer, "\n");
+    if (token.empty()) {
+      break;
+    }
+    result->push_back((manifest_path / std::string_view(token)).native());
+    buffer = remainder;
+  }
+
+  if (result->empty()) {
+    result = ErrorBuilder()
+             << "Manifest `" << (manifest_path / manifest_file) << "` is empty";
+  }
+  return result;
+}
+
+auto InstallPaths::MakeFromFile(std::filesystem::path file_path)
+    -> InstallPaths {
+  // TODO: Detect a Windows executable path and use custom logic to map to the
+  // correct install prefix for that platform.
+  //
+  // We assume an executable will be in a `bin` directory and this is a
+  // FHS-like install prefix. We remove the filename and walk up to find the
+  // expected install prefix.
+  std::error_code ec;
+  InstallPaths paths(std::filesystem::absolute(
+      std::move(file_path).remove_filename() / "../..", ec));
+  if (ec) {
+    paths.SetError(ec.message());
+    return paths;
+  }
+
+  auto open_result = Filesystem::Cwd().OpenDir(paths.prefix_);
+  if (!open_result.ok()) {
+    paths.SetError(open_result.error().ToString());
+    return paths;
+  }
+
+  paths.prefix_dir_ = *std::move(open_result);
+  paths.CheckMarkerFile();
+  return paths;
+}
+
+auto InstallPaths::SetError(llvm::Twine message) -> void {
+  // Use an empty prefix on error as that should use the working directory which
+  // is the least likely problematic.
+  prefix_ = "";
+  prefix_dir_ = Filesystem::Dir();
+  error_ = {message.str()};
+}
+
+auto InstallPaths::CheckMarkerFile() -> void {
+  if (!prefix_.is_absolute()) {
+    SetError(llvm::Twine("Not an absolute path: ") + prefix_.native());
+    return;
+  }
+
+  auto access_result = prefix_dir_.Access(MarkerPath.str());
+  if (!access_result.ok()) {
+    SetError(access_result.error().ToString());
+    return;
+  }
+  if (!*access_result) {
+    SetError(llvm::Twine("No install marker at path: ") +
+             (prefix_ / std::string_view(MarkerPath)).native());
+    return;
+  }
+
+  // Success!
+}
+
+auto InstallPaths::core_package() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/core";
+}
+
+auto InstallPaths::llvm_install_bin() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin/";
+}
+
+auto InstallPaths::clang_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin/clang";
+}
+
+auto InstallPaths::lld_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin/lld";
+}
+
+auto InstallPaths::ld_lld_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin/ld.lld";
+}
+
+auto InstallPaths::ld64_lld_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin/ld64.lld";
+}
+
+auto InstallPaths::llvm_tool_path(LLVMTool tool) const
+    -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/bin" / std::string_view(tool.bin_name());
+}
+
+auto InstallPaths::clang_resource_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/llvm/lib/clang/" CLANG_VERSION_MAJOR_STRING;
+}
+
+auto InstallPaths::runtimes_root() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/runtimes";
+}
+
+auto InstallPaths::libunwind_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/runtimes/libunwind";
+}
+
+auto InstallPaths::libcxx_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/runtimes/libcxx";
+}
+
+auto InstallPaths::libcxxabi_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/runtimes/libcxxabi";
+}
+
+auto InstallPaths::libc_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/runtimes/libc";
+}
+
+auto InstallPaths::digest_path() const -> std::filesystem::path {
+  // TODO: Adjust this to work equally well on Windows.
+  return prefix_ / "lib/carbon/install_digest.txt";
+}
+
+}  // namespace Carbon