//===-- FileSpec.h ----------------------------------------------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLDB_UTILITY_FILESPEC_H
#define LLDB_UTILITY_FILESPEC_H

#include <functional>
#include <optional>
#include <string>

#include "lldb/Utility/Checksum.h"
#include "lldb/Utility/ConstString.h"

#include "llvm/ADT/StringRef.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"

#include <cstddef>
#include <cstdint>

namespace lldb_private {
class Stream;
}
namespace llvm {
class Triple;
}
namespace llvm {
class raw_ostream;
}
namespace llvm {
template <typename T> class SmallVectorImpl;
}

namespace lldb_private {

/// \class FileSpec FileSpec.h "lldb/Utility/FileSpec.h"
/// A file utility class.
///
/// A file specification class that divides paths up into a directory
/// and basename. These string values of the paths are put into uniqued string
/// pools for fast comparisons and efficient memory usage.
///
/// Another reason the paths are split into the directory and basename is to
/// allow efficient debugger searching. Often in a debugger the user types in
/// the basename of the file, for example setting a breakpoint by file and
/// line, or specifying a module (shared library) to limit the scope in which
/// to execute a command. The user rarely types in a full path. When the paths
/// are already split up, it makes it easy for us to compare only the
/// basenames of a lot of file specifications without having to split up the
/// file path each time to get to the basename.
class FileSpec {
public:
  using Style = llvm::sys::path::Style;

  FileSpec();

  /// Constructor with path.
  ///
  /// Takes a path to a file which can be just a filename, or a full path. If
  /// \a path is not nullptr or empty, this function will call
  /// FileSpec::SetFile (const char *path).
  ///
  /// \param[in] path
  ///     The full or partial path to a file.
  ///
  /// \param[in] style
  ///     The style of the path
  ///
  /// \param[in] checksum
  ///     The MD5 checksum of the path.
  ///
  /// \see FileSpec::SetFile (const char *path)
  explicit FileSpec(llvm::StringRef path, Style style = Style::native,
                    const Checksum &checksum = {});

  explicit FileSpec(llvm::StringRef path, const llvm::Triple &triple);

  bool DirectoryEquals(const FileSpec &other) const;

  bool FileEquals(const FileSpec &other) const;

  /// Equal to operator
  ///
  /// Tests if this object is equal to \a rhs.
  ///
  /// \param[in] rhs
  ///     A const FileSpec object reference to compare this object
  ///     to.
  ///
  /// \return
  ///     \b true if this object is equal to \a rhs, \b false
  ///     otherwise.
  bool operator==(const FileSpec &rhs) const;

  /// Not equal to operator
  ///
  /// Tests if this object is not equal to \a rhs.
  ///
  /// \param[in] rhs
  ///     A const FileSpec object reference to compare this object
  ///     to.
  ///
  /// \return
  ///     \b true if this object is equal to \a rhs, \b false
  ///     otherwise.
  bool operator!=(const FileSpec &rhs) const;

  /// Less than to operator
  ///
  /// Tests if this object is less than \a rhs.
  ///
  /// \param[in] rhs
  ///     A const FileSpec object reference to compare this object
  ///     to.
  ///
  /// \return
  ///     \b true if this object is less than \a rhs, \b false
  ///     otherwise.
  bool operator<(const FileSpec &rhs) const;

  /// Convert to pointer operator.
  ///
  /// This allows code to check a FileSpec object to see if it contains
  /// anything valid using code such as:
  ///
  /// \code
  /// FileSpec file_spec(...);
  /// if (file_spec)
  /// { ...
  /// \endcode
  ///
  /// \return
  ///     A pointer to this object if either the directory or filename
  ///     is valid, nullptr otherwise.
  explicit operator bool() const;

  /// Logical NOT operator.
  ///
  /// This allows code to check a FileSpec object to see if it is invalid
  /// using code such as:
  ///
  /// \code
  /// FileSpec file_spec(...);
  /// if (!file_spec)
  /// { ...
  /// \endcode
  ///
  /// \return
  ///     Returns \b true if the object has an empty directory and
  ///     filename, \b false otherwise.
  bool operator!() const;

  /// Clears the object state.
  ///
  /// Clear this object by releasing both the directory and filename string
  /// values and reverting them to empty strings.
  void Clear();

  /// Compare two FileSpec objects.
  ///
  /// If \a full is true, then both the directory and the filename must match.
  /// If \a full is false, then the directory names for \a lhs and \a rhs are
  /// only compared if they are both not empty. This allows a FileSpec object
  /// to only contain a filename and it can match FileSpec objects that have
  /// matching filenames with different paths.
  ///
  /// \param[in] lhs
  ///     A const reference to the Left Hand Side object to compare.
  ///
  /// \param[in] rhs
  ///     A const reference to the Right Hand Side object to compare.
  ///
  /// \param[in] full
  ///     If true, then both the directory and filenames will have to
  ///     match for a compare to return zero (equal to). If false
  ///     and either directory from \a lhs or \a rhs is empty, then
  ///     only the filename will be compared, else a full comparison
  ///     is done.
  ///
  /// \return -1 if \a lhs is less than \a rhs, 0 if \a lhs is equal to \a rhs,
  ///     1 if \a lhs is greater than \a rhs
  static int Compare(const FileSpec &lhs, const FileSpec &rhs, bool full);

  static bool Equal(const FileSpec &a, const FileSpec &b, bool full);

  /// Match FileSpec \a pattern against FileSpec \a file. If \a pattern has a
  /// directory component, then the \a file must have the same directory
  /// component. Otherwise, just it matches just the filename. An empty \a
  /// pattern matches everything.
  static bool Match(const FileSpec &pattern, const FileSpec &file);

  /// Attempt to guess path style for a given path string. It returns a style,
  /// if it was able to make a reasonable guess, or std::nullopt if it wasn't.
  /// The guess will be correct if the input path was a valid absolute path on
  /// the system which produced it. On other paths the result of this function
  /// is unreliable (e.g. "c:\foo.txt" is a valid relative posix path).
  static std::optional<Style> GuessPathStyle(llvm::StringRef absolute_path);

  /// Case sensitivity of path.
  ///
  /// \return
  ///     \b true if the file path is case sensitive (POSIX), false
  ///		if case insensitive (Windows).
  bool IsCaseSensitive() const { return is_style_posix(m_style); }

  /// Dump this object to a Stream.
  ///
  /// Dump the object to the supplied stream \a s. If the object contains a
  /// valid directory name, it will be displayed followed by a directory
  /// delimiter, and the filename.
  ///
  /// \param[in] s
  ///     The stream to which to dump the object description.
  void Dump(llvm::raw_ostream &s) const;

  Style GetPathStyle() const;

  /// Directory string const get accessor.
  ///
  /// \return
  ///     A const reference to the directory string object.
  const ConstString &GetDirectory() const { return m_directory; }

  /// Directory string set accessor.
  ///
  /// \param[in] directory
  ///     The value to replace the directory with.
  void SetDirectory(ConstString directory);
  void SetDirectory(llvm::StringRef directory);

  /// Clear the directory in this object.
  void ClearDirectory();


  /// Filename string const get accessor.
  ///
  /// \return
  ///     A const reference to the filename string object.
  const ConstString &GetFilename() const { return m_filename; }

  /// Filename string set accessor.
  ///
  /// \param[in] filename
  ///     The const string to replace the directory with.
  void SetFilename(ConstString filename);
  void SetFilename(llvm::StringRef filename);

  /// Clear the filename in this object.
  void ClearFilename();

  /// Returns true if the filespec represents an implementation source file
  /// (files with a ".c", ".cpp", ".m", ".mm" (many more) extension).
  ///
  /// \return
  ///     \b true if the FileSpec represents an implementation source
  ///     file, \b false otherwise.
  bool IsSourceImplementationFile() const;

  /// Returns true if the filespec represents a relative path.
  ///
  /// \return
  ///     \b true if the filespec represents a relative path,
  ///     \b false otherwise.
  bool IsRelative() const;

  /// Returns true if the filespec represents an absolute path.
  ///
  /// \return
  ///     \b true if the filespec represents an absolute path,
  ///     \b false otherwise.
  bool IsAbsolute() const;

  /// Make the FileSpec absolute by treating it relative to \a dir. Absolute
  /// FileSpecs are never changed by this function.
  void MakeAbsolute(const FileSpec &dir);

  /// Temporary helper for FileSystem change.
  void SetPath(llvm::StringRef p) { SetFile(p); }

  /// Extract the full path to the file.
  ///
  /// Extract the directory and path into a fixed buffer. This is needed as
  /// the directory and path are stored in separate string values.
  ///
  /// \param[out] path
  ///     The buffer in which to place the extracted full path.
  ///
  /// \param[in] max_path_length
  ///     The maximum length of \a path.
  ///
  /// \return
  ///     Returns the number of characters that would be needed to
  ///     properly copy the full path into \a path. If the returned
  ///     number is less than \a max_path_length, then the path is
  ///     properly copied and terminated. If the return value is
  ///     >= \a max_path_length, then the path was truncated (but is
  ///     still NULL terminated).
  size_t GetPath(char *path, size_t max_path_length,
                 bool denormalize = true) const;

  /// Extract the full path to the file.
  ///
  /// Extract the directory and path into a std::string, which is returned.
  ///
  /// \return
  ///     Returns a std::string with the directory and filename
  ///     concatenated.
  std::string GetPath(bool denormalize = true) const;

  /// Get the full path as a ConstString.
  ///
  /// This method should only be used when you need a ConstString or the
  /// const char * from a ConstString to ensure permanent lifetime of C string.
  /// Anyone needing the path temporarily should use the GetPath() method that
  /// returns a std:string.
  ConstString GetPathAsConstString(bool denormalize = true) const;

  /// Extract the full path to the file.
  ///
  /// Extract the directory and path into an llvm::SmallVectorImpl<>
  void GetPath(llvm::SmallVectorImpl<char> &path,
               bool denormalize = true) const;

  /// Extract the extension of the file.
  ///
  /// Returns a ConstString that represents the extension of the filename for
  /// this FileSpec object. If this object does not represent a file, or the
  /// filename has no extension, ConstString(nullptr) is returned. The dot
  /// ('.') character is the first character in the returned string.
  ///
  /// \return Returns the extension of the file as a StringRef.
  llvm::StringRef GetFileNameExtension() const;

  /// Return the filename without the extension part
  ///
  /// Returns a ConstString that represents the filename of this object
  /// without the extension part (e.g. for a file named "foo.bar", "foo" is
  /// returned)
  ///
  /// \return Returns the filename without extension as a ConstString object.
  ConstString GetFileNameStrippingExtension() const;

  /// Get the memory cost of this object.
  ///
  /// Return the size in bytes that this object takes in memory. This returns
  /// the size in bytes of this object, not any shared string values it may
  /// refer to.
  ///
  /// \return
  ///     The number of bytes that this object occupies in memory.
  size_t MemorySize() const;

  /// Change the file specified with a new path.
  ///
  /// Update the contents of this object with a new path. The path will be
  /// split up into a directory and filename and stored as uniqued string
  /// values for quick comparison and efficient memory usage.
  ///
  /// \param[in] path
  ///     A full, partial, or relative path to a file.
  ///
  /// \param[in] style
  ///     The style for the given path.
  ///
  /// \param[in] checksum
  ///     The checksum for the given path.
  void SetFile(llvm::StringRef path, Style style,
               const Checksum &checksum = {});

  /// Change the file specified with a new path.
  ///
  /// Update the contents of this object with a new path. The path will be
  /// split up into a directory and filename and stored as uniqued string
  /// values for quick comparison and efficient memory usage.
  ///
  /// \param[in] path
  ///     A full, partial, or relative path to a file.
  ///
  /// \param[in] triple
  ///     The triple which is used to set the Path style.
  void SetFile(llvm::StringRef path, const llvm::Triple &triple);

  FileSpec CopyByAppendingPathComponent(llvm::StringRef component) const;
  FileSpec CopyByRemovingLastPathComponent() const;

  void PrependPathComponent(llvm::StringRef component);
  void PrependPathComponent(const FileSpec &new_path);

  void AppendPathComponent(llvm::StringRef component);
  void AppendPathComponent(const FileSpec &new_path);

  /// Removes the last path component by replacing the current path with its
  /// parent. When the current path has no parent, this is a no-op.
  ///
  /// \return
  ///     A boolean value indicating whether the path was updated.
  bool RemoveLastPathComponent();

  /// Gets the components of the FileSpec's path.
  /// For example, given the path:
  ///   /System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation
  ///
  /// This function returns:
  ///   {"System", "Library", "PrivateFrameworks", "UIFoundation.framework",
  ///   "UIFoundation"}
  /// \return
  ///   A std::vector of llvm::StringRefs for each path component.
  ///   The lifetime of the StringRefs is tied to the lifetime of the FileSpec.
  std::vector<llvm::StringRef> GetComponents() const;

  /// Return the checksum for this FileSpec or all zeros if there is none.
  const Checksum &GetChecksum() const { return m_checksum; };

protected:
  // Convenience method for setting the file without changing the style.
  void SetFile(llvm::StringRef path);

  /// Called anytime m_directory or m_filename is changed to clear any cached
  /// state in this object.
  void PathWasModified() {
    m_checksum = Checksum();
    m_absolute = Absolute::Calculate;
  }

  enum class Absolute : uint8_t {
    Calculate,
    Yes,
    No
  };

  /// The unique'd directory path.
  ConstString m_directory;

  /// The unique'd filename path.
  ConstString m_filename;

  /// The optional MD5 checksum of the file.
  Checksum m_checksum;

  /// Cache whether this path is absolute.
  mutable Absolute m_absolute = Absolute::Calculate;

  /// The syntax that this path uses. (e.g. Windows / Posix)
  Style m_style;
};

/// Dump a FileSpec object to a stream
Stream &operator<<(Stream &s, const FileSpec &f);
} // namespace lldb_private

namespace llvm {

/// Implementation of format_provider<T> for FileSpec.
///
/// The options string of a FileSpec has the grammar:
///
///   file_spec_options   :: (empty) | F | D
///
///   =======================================================
///   |  style  |     Meaning          |      Example       |
///   -------------------------------------------------------
///   |         |                      |  Input   |  Output |
///   =======================================================
///   |    F    | Only print filename  | /foo/bar |   bar   |
///   |    D    | Only print directory | /foo/bar |  /foo/  |
///   | (empty) | Print file and dir   |          |         |
///   =======================================================
///
/// Any other value is considered an invalid format string.
///
template <> struct format_provider<lldb_private::FileSpec> {
  static void format(const lldb_private::FileSpec &F, llvm::raw_ostream &Stream,
                     StringRef Style);
};

} // namespace llvm

#endif // LLDB_UTILITY_FILESPEC_H