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//===-- File.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 liblldb_File_h_
#define liblldb_File_h_
#include "lldb/Host/PosixApi.h"
#include "lldb/Utility/IOObject.h"
#include "lldb/Utility/Status.h"
#include "lldb/lldb-private.h"
#include <mutex>
#include <stdarg.h>
#include <stdio.h>
#include <sys/types.h>
namespace lldb_private {
/// \class File File.h "lldb/Host/File.h"
/// A file class.
///
/// A file class that divides abstracts the LLDB core from host file
/// functionality.
class File : public IOObject {
public:
static int kInvalidDescriptor;
static FILE *kInvalidStream;
// NB this enum is used in the lldb platform gdb-remote packet
// vFile:open: and existing values cannot be modified.
enum OpenOptions {
eOpenOptionRead = (1u << 0), // Open file for reading
eOpenOptionWrite = (1u << 1), // Open file for writing
eOpenOptionAppend =
(1u << 2), // Don't truncate file when opening, append to end of file
eOpenOptionTruncate = (1u << 3), // Truncate file when opening
eOpenOptionNonBlocking = (1u << 4), // File reads
eOpenOptionCanCreate = (1u << 5), // Create file if doesn't already exist
eOpenOptionCanCreateNewOnly =
(1u << 6), // Can create file only if it doesn't already exist
eOpenOptionDontFollowSymlinks = (1u << 7),
eOpenOptionCloseOnExec =
(1u << 8) // Close the file when executing a new process
};
static mode_t ConvertOpenOptionsForPOSIXOpen(uint32_t open_options);
File()
: IOObject(eFDTypeFile, false), m_descriptor(kInvalidDescriptor),
m_stream(kInvalidStream), m_options(0), m_own_stream(false),
m_is_interactive(eLazyBoolCalculate),
m_is_real_terminal(eLazyBoolCalculate),
m_supports_colors(eLazyBoolCalculate) {}
File(FILE *fh, bool transfer_ownership)
: IOObject(eFDTypeFile, false), m_descriptor(kInvalidDescriptor),
m_stream(fh), m_options(0), m_own_stream(transfer_ownership),
m_is_interactive(eLazyBoolCalculate),
m_is_real_terminal(eLazyBoolCalculate),
m_supports_colors(eLazyBoolCalculate) {}
File(int fd, bool transfer_ownership)
: IOObject(eFDTypeFile, transfer_ownership), m_descriptor(fd),
m_stream(kInvalidStream), m_options(0), m_own_stream(false),
m_is_interactive(eLazyBoolCalculate),
m_is_real_terminal(eLazyBoolCalculate) {}
/// Destructor.
///
/// The destructor is virtual in case this class is subclassed.
~File() override;
bool IsValid() const override {
return DescriptorIsValid() || StreamIsValid();
}
/// Convert to pointer operator.
///
/// This allows code to check a File object to see if it contains anything
/// valid using code such as:
///
/// \code
/// File file(...);
/// if (file)
/// { ...
/// \endcode
///
/// \return
/// A pointer to this object if either the directory or filename
/// is valid, nullptr otherwise.
operator bool() const { return DescriptorIsValid() || StreamIsValid(); }
/// Logical NOT operator.
///
/// This allows code to check a File object to see if it is invalid using
/// code such as:
///
/// \code
/// File file(...);
/// if (!file)
/// { ...
/// \endcode
///
/// \return
/// Returns \b true if the object has an empty directory and
/// filename, \b false otherwise.
bool operator!() const { return !DescriptorIsValid() && !StreamIsValid(); }
/// Get the file spec for this file.
///
/// \return
/// A reference to the file specification object.
Status GetFileSpec(FileSpec &file_spec) const;
Status Close() override;
void Clear();
int GetDescriptor() const;
WaitableHandle GetWaitableHandle() override;
void SetDescriptor(int fd, bool transfer_ownership);
FILE *GetStream();
void SetStream(FILE *fh, bool transfer_ownership);
/// Read bytes from a file from the current file position.
///
/// NOTE: This function is NOT thread safe. Use the read function
/// that takes an "off_t &offset" to ensure correct operation in multi-
/// threaded environments.
///
/// \param[in] buf
/// A buffer where to put the bytes that are read.
///
/// \param[in,out] num_bytes
/// The number of bytes to read form the current file position
/// which gets modified with the number of bytes that were read.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Read(void *buf, size_t &num_bytes) override;
/// Write bytes to a file at the current file position.
///
/// NOTE: This function is NOT thread safe. Use the write function
/// that takes an "off_t &offset" to ensure correct operation in multi-
/// threaded environments.
///
/// \param[in] buf
/// A buffer where to put the bytes that are read.
///
/// \param[in,out] num_bytes
/// The number of bytes to write to the current file position
/// which gets modified with the number of bytes that were
/// written.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Write(const void *buf, size_t &num_bytes) override;
/// Seek to an offset relative to the beginning of the file.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in] offset
/// The offset to seek to within the file relative to the
/// beginning of the file.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
off_t SeekFromStart(off_t offset, Status *error_ptr = nullptr);
/// Seek to an offset relative to the current file position.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in] offset
/// The offset to seek to within the file relative to the
/// current file position.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
off_t SeekFromCurrent(off_t offset, Status *error_ptr = nullptr);
/// Seek to an offset relative to the end of the file.
///
/// NOTE: This function is NOT thread safe, other threads that
/// access this object might also change the current file position. For
/// thread safe reads and writes see the following functions: @see
/// File::Read (void *, size_t, off_t &) \see File::Write (const void *,
/// size_t, off_t &)
///
/// \param[in,out] offset
/// The offset to seek to within the file relative to the
/// end of the file which gets filled in with the resulting
/// absolute file offset.
///
/// \param[in] error_ptr
/// A pointer to a lldb_private::Status object that will be
/// filled in if non-nullptr.
///
/// \return
/// The resulting seek offset, or -1 on error.
off_t SeekFromEnd(off_t offset, Status *error_ptr = nullptr);
/// Read bytes from a file from the specified file offset.
///
/// NOTE: This function is thread safe in that clients manager their
/// own file position markers and reads on other threads won't mess up the
/// current read.
///
/// \param[in] dst
/// A buffer where to put the bytes that are read.
///
/// \param[in,out] num_bytes
/// The number of bytes to read form the current file position
/// which gets modified with the number of bytes that were read.
///
/// \param[in,out] offset
/// The offset within the file from which to read \a num_bytes
/// bytes. This offset gets incremented by the number of bytes
/// that were read.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Read(void *dst, size_t &num_bytes, off_t &offset);
/// Read bytes from a file from the specified file offset.
///
/// NOTE: This function is thread safe in that clients manager their
/// own file position markers and reads on other threads won't mess up the
/// current read.
///
/// \param[in,out] num_bytes
/// The number of bytes to read form the current file position
/// which gets modified with the number of bytes that were read.
///
/// \param[in,out] offset
/// The offset within the file from which to read \a num_bytes
/// bytes. This offset gets incremented by the number of bytes
/// that were read.
///
/// \param[in] null_terminate
/// Ensure that the data that is read is terminated with a NULL
/// character so that the data can be used as a C string.
///
/// \param[out] data_buffer_sp
/// A data buffer to create and fill in that will contain any
/// data that is read from the file. This buffer will be reset
/// if an error occurs.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Read(size_t &num_bytes, off_t &offset, bool null_terminate,
lldb::DataBufferSP &data_buffer_sp);
/// Write bytes to a file at the specified file offset.
///
/// NOTE: This function is thread safe in that clients manager their
/// own file position markers, though clients will need to implement their
/// own locking externally to avoid multiple people writing to the file at
/// the same time.
///
/// \param[in] src
/// A buffer containing the bytes to write.
///
/// \param[in,out] num_bytes
/// The number of bytes to write to the file at offset \a offset.
/// \a num_bytes gets modified with the number of bytes that
/// were read.
///
/// \param[in,out] offset
/// The offset within the file at which to write \a num_bytes
/// bytes. This offset gets incremented by the number of bytes
/// that were written.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Write(const void *src, size_t &num_bytes, off_t &offset);
/// Flush the current stream
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Flush();
/// Sync to disk.
///
/// \return
/// An error object that indicates success or the reason for
/// failure.
Status Sync();
/// Get the permissions for a this file.
///
/// \return
/// Bits logical OR'ed together from the permission bits defined
/// in lldb_private::File::Permissions.
uint32_t GetPermissions(Status &error) const;
/// Return true if this file is interactive.
///
/// \return
/// True if this file is a terminal (tty or pty), false
/// otherwise.
bool GetIsInteractive();
/// Return true if this file from a real terminal.
///
/// Just knowing a file is a interactive isn't enough, we also need to know
/// if the terminal has a width and height so we can do cursor movement and
/// other terminal manipulations by sending escape sequences.
///
/// \return
/// True if this file is a terminal (tty, not a pty) that has
/// a non-zero width and height, false otherwise.
bool GetIsRealTerminal();
bool GetIsTerminalWithColors();
/// Output printf formatted output to the stream.
///
/// Print some formatted output to the stream.
///
/// \param[in] format
/// A printf style format string.
///
/// \param[in] ...
/// Variable arguments that are needed for the printf style
/// format string \a format.
size_t Printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
size_t PrintfVarArg(const char *format, va_list args);
void SetOptions(uint32_t options) { m_options = options; }
static bool DescriptorIsValid(int descriptor) { return descriptor >= 0; };
protected:
bool DescriptorIsValid() const { return DescriptorIsValid(m_descriptor); }
bool StreamIsValid() const { return m_stream != kInvalidStream; }
void CalculateInteractiveAndTerminal();
// Member variables
int m_descriptor;
FILE *m_stream;
uint32_t m_options;
bool m_own_stream;
LazyBool m_is_interactive;
LazyBool m_is_real_terminal;
LazyBool m_supports_colors;
std::mutex offset_access_mutex;
private:
DISALLOW_COPY_AND_ASSIGN(File);
};
} // namespace lldb_private
#endif // liblldb_File_h_