1 files changed, 72 insertions, 0 deletions
diff --git a/src/nvim/os/fileio.h b/src/nvim/os/fileio.h
new file mode 100644
index 0000000000..2cffd5c851
--- /dev/null
+++ b/src/nvim/os/fileio.h
@@ -0,0 +1,72 @@
+#ifndef NVIM_OS_FILEIO_H
+#define NVIM_OS_FILEIO_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "nvim/func_attr.h"
+#include "nvim/rbuffer.h"
+
+/// Structure used to read from/write to file
+typedef struct {
+  int fd;  ///< File descriptor.
+  int _error;  ///< Error code for use with RBuffer callbacks or zero.
+  RBuffer *rv;  ///< Read or write buffer.
+  bool wr;  ///< True if file is in write mode.
+  bool eof;  ///< True if end of file was encountered.
+} FileDescriptor;
+
+/// file_open() flags
+typedef enum {
+  kFileReadOnly = 1,  ///< Open file read-only. Default.
+  kFileCreate = 2,  ///< Create file if it does not exist yet.
+                    ///< Implies kFileWriteOnly.
+  kFileWriteOnly = 4,  ///< Open file for writing only.
+                       ///< Cannot be used with kFileReadOnly.
+  kFileNoSymlink = 8,  ///< Do not allow symbolic links.
+  kFileCreateOnly = 16,  ///< Only create the file, failing if it already
+                         ///< exists. Implies kFileWriteOnly. Cannot be used
+                         ///< with kFileCreate.
+  kFileTruncate = 32,  ///< Truncate the file if it exists.
+                       ///< Implies kFileWriteOnly. Cannot be used with
+                       ///< kFileCreateOnly.
+} FileOpenFlags;
+
+static inline bool file_eof(const FileDescriptor *const fp)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
+
+/// Check whether end of file was encountered
+///
+/// @param[in]  fp  File to check.
+///
+/// @return true if it was, false if it was not or read operation was never
+///         performed.
+static inline bool file_eof(const FileDescriptor *const fp)
+{
+  return fp->eof && rbuffer_size(fp->rv) == 0;
+}
+
+static inline int file_fd(const FileDescriptor *const fp)
+  REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
+
+/// Return the file descriptor associated with the FileDescriptor structure
+///
+/// @param[in]  fp  File to check.
+///
+/// @return File descriptor.
+static inline int file_fd(const FileDescriptor *const fp)
+{
+  return fp->fd;
+}
+
+enum {
+  /// Read or write buffer size
+  ///
+  /// Currently equal to (IOSIZE - 1), but they do not need to be connected.
+  kRWBufferSize = 1024
+};
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/fileio.h.generated.h"
+#endif
+#endif  // NVIM_OS_FILEIO_H