ClangFormat: Support remote filesystems

Change-Id: Ic5c06a826154e1bee92e3c283ab508177e86c428
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>

src/plugins/clangformat/clangformatbaseindenter.cpp

@@ -5,6 +5,7 @@
 #include "clangformatconstants.h"
 #include "clangformatsettings.h"
 #include "clangformatutils.h"
+#include "llvmfilesystem.h"
 
 #include <coreplugin/icore.h>
 #include <projectexplorer/editorconfiguration.h>
@@ -25,6 +26,8 @@
 
 namespace ClangFormat {
 
+Internal::LlvmFileSystemAdapter llvmFileSystemAdapter;
+
 namespace {
 void adjustFormatStyleForLineBreak(clang::format::FormatStyle &style,
                                    ReplacementsToKeep replacementsToKeep)
@@ -735,8 +738,8 @@ void ClangFormatBaseIndenter::autoIndent(const QTextCursor &cursor,
 
 clang::format::FormatStyle ClangFormatBaseIndenter::styleForFile() const
 {
-    llvm::Expected<clang::format::FormatStyle> styleFromProjectFolder
-        = clang::format::getStyle("file", m_fileName.path().toStdString(), "none");
+    llvm::Expected<clang::format::FormatStyle> styleFromProjectFolder = clang::format::getStyle(
+        "file", m_fileName.toFSPathString().toStdString(), "none", "", &llvmFileSystemAdapter);
 
     const ProjectExplorer::Project *projectForFile
         = ProjectExplorer::SessionManager::projectForFile(m_fileName);
@@ -748,7 +751,7 @@ clang::format::FormatStyle ClangFormatBaseIndenter::styleForFile() const
               ? projectForFile->editorConfiguration()->codeStyle("Cpp")->currentPreferences()
               : TextEditor::TextEditorSettings::codeStyle("Cpp")->currentPreferences();
 
-    if (overrideStyleFile || !styleFromProjectFolder
+    if (!styleFromProjectFolder || overrideStyleFile
         || *styleFromProjectFolder == clang::format::getNoStyle()) {
         Utils::FilePath filePath = filePathToCurrentSettings(preferences);
 

src/plugins/clangformat/llvmfilesystem.h

@@ -0,0 +1,171 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include <utils/filepath.h>
+#include <utils/qtcassert.h>
+
+#include <llvm/Support/VirtualFileSystem.h>
+
+namespace ClangFormat::Internal {
+
+using namespace llvm;
+using namespace llvm::vfs;
+using namespace llvm::sys::fs;
+using namespace Utils;
+
+class LlvmFileAdapter : public File
+{
+public:
+    LlvmFileAdapter(const Twine &Path)
+        : m_path(FilePath::fromString(QString::fromStdString(Path.str())))
+    {}
+    /// Destroy the file after closing it (if open).
+    /// Sub-classes should generally call close() inside their destructors.  We
+    /// cannot do that from the base class, since close is virtual.
+    ~LlvmFileAdapter() { close(); }
+
+    /// Get the status of the file.
+    ErrorOr<Status> status() override
+    {
+        Q_UNIMPLEMENTED();
+        return std::make_error_code(std::errc::not_supported);
+    }
+
+    /// Get the name of the file
+    ErrorOr<std::string> getName() override
+    {
+        Q_UNIMPLEMENTED();
+        return std::make_error_code(std::errc::not_supported);
+    }
+
+    /// Get the contents of the file as a \p MemoryBuffer.
+    ErrorOr<std::unique_ptr<MemoryBuffer>> getBuffer(const Twine &Name,
+                                                     int64_t FileSize = -1,
+                                                     bool RequiresNullTerminator = true,
+                                                     bool IsVolatile = false) override
+    {
+        Q_UNUSED(RequiresNullTerminator);
+        Q_UNUSED(IsVolatile);
+
+        const FilePath path = FilePath::fromString(QString::fromStdString(Name.str()));
+        const std::optional<QByteArray> contents = path.fileContents(FileSize, 0);
+        QTC_ASSERT(contents, return std::error_code());
+
+        return MemoryBuffer::getMemBufferCopy(contents->data(), Name);
+    }
+
+    /// Closes the file.
+    std::error_code close() override { return {}; }
+
+protected:
+    // Set the file's underlying path.
+    void setPath(const Twine &Path) override
+    {
+        m_path = FilePath::fromString(QString::fromStdString(Path.str()));
+    }
+
+    FilePath m_path;
+};
+
+class LlvmFileSystemAdapter : public FileSystem
+{
+public:
+    LlvmFileSystemAdapter()
+        : m_workingDirectory(FilePath::currentWorkingPath())
+    {}
+
+    ErrorOr<Status> status(const Twine &Path) override
+    {
+        const Utils::FilePath path = FilePath::fromString(QString::fromStdString(Path.str()));
+
+        QFileInfo fInfo(QString::fromStdString(Path.str()));
+        if (!fInfo.exists())
+            return std::error_code();
+
+        const std::chrono::seconds modInSeconds = std::chrono::seconds(
+            fInfo.lastModified().toSecsSinceEpoch());
+        const std::chrono::time_point<std::chrono::system_clock> modTime(modInSeconds);
+        file_type type = file_type::status_error;
+        if (fInfo.isDir())
+            type = file_type::directory_file;
+        else if (fInfo.isFile())
+            type = file_type::regular_file;
+        else
+            QTC_ASSERT(false, return std::error_code());
+
+        Status result(Path, {0, 0}, modTime, 0, 0, fInfo.size(), type, perms::all_perms);
+        return result;
+    };
+
+    virtual ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override
+    {
+        return std::make_unique<LlvmFileAdapter>(Path);
+    }
+
+    /// Get a directory_iterator for \p Dir.
+    /// \note The 'end' iterator is directory_iterator().
+    vfs::directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override
+    {
+        Q_UNIMPLEMENTED();
+        return {};
+    }
+
+    /// Set the working directory. This will affect all following operations on
+    /// this file system and may propagate down for nested file systems.
+    std::error_code setCurrentWorkingDirectory(const Twine &Path) override
+    {
+        Q_UNUSED(Path);
+        Q_UNIMPLEMENTED();
+        return std::make_error_code(std::errc::not_supported);
+    }
+
+    /// Get the working directory of this file system.
+    ErrorOr<std::string> getCurrentWorkingDirectory() const override
+    {
+        Q_UNIMPLEMENTED();
+        return std::make_error_code(std::errc::not_supported);
+    }
+
+    /// Gets real path of \p Path e.g. collapse all . and .. patterns, resolve
+    /// symlinks. For real file system, this uses `llvm::sys::fs::real_path`.
+    /// This returns errc::operation_not_permitted if not implemented by subclass.
+    std::error_code getRealPath(const Twine &Path, SmallVectorImpl<char> &Output) const override
+    {
+        Q_UNUSED(Path);
+        Q_UNUSED(Output);
+
+        Q_UNIMPLEMENTED();
+        return std::make_error_code(std::errc::not_supported);
+    }
+
+    /// Is the file mounted on a local filesystem?
+    std::error_code isLocal(const Twine &Path, bool &Result) override
+    {
+        const FilePath filePath = FilePath::fromString(QString::fromStdString(Path.str()));
+        Result = !filePath.needsDevice();
+        return {};
+    }
+
+    std::error_code makeAbsolute(SmallVectorImpl<char> &Path) const override
+    {
+        if (Path.empty()) {
+            const std::string asString = m_workingDirectory.toFSPathString().toStdString();
+            Path.assign(asString.begin(), asString.end());
+            return {};
+        }
+        const FilePath filePath = FilePath::fromString(QString::fromStdString(Path.data()));
+        if (filePath.isRelativePath()) {
+            const std::string asString
+                = m_workingDirectory.resolvePath(filePath).toFSPathString().toStdString();
+            Path.assign(asString.begin(), asString.end());
+        }
+        return {};
+    }
+
+private:
+    FilePath m_workingDirectory;
+};
+
+} // namespace ClangFormat::Internal