src/lib/istream-private.h

	istream-private.h revision 82ea464c113f43aaa2b2e23de334cf3081c332be
#ifndef ISTREAM_PRIVATE_H
#define ISTREAM_PRIVATE_H

#include "istream.h"
#include "iostream-private.h"

#define I_STREAM_MIN_SIZE IO_BLOCK_SIZE

struct io;

struct istream_private {
/* inheritance: */
    struct iostream_private iostream;

/* methods: */
    ssize_t (*read)(struct istream_private *stream);
    void (*seek)(struct istream_private *stream,
             uoff_t v_offset, bool mark);
    void (*sync)(struct istream_private *stream);
    int (*stat)(struct istream_private *stream, bool exact);
    int (*get_size)(struct istream_private *stream, bool exact, uoff_t *size_r);
    void (*switch_ioloop)(struct istream_private *stream);
    struct istream_snapshot *
        (*snapshot)(struct istream_private *stream,
                struct istream_snapshot *prev_snapshot);

/* data: */
    struct istream istream;

    int fd;
    uoff_t start_offset;
    struct stat statbuf;
    /* added by io_add_istream() -> i_stream_set_io() */
    struct io *io;

    const unsigned char *buffer;
    unsigned char *w_buffer; /* may be NULL */

    size_t buffer_size, max_buffer_size, init_buffer_size;
    size_t skip, pos, try_alloc_limit;

    struct istream *parent; /* for filter streams */
    uoff_t parent_start_offset;

    /* parent stream's expected offset is kept here. i_stream_read()
       always seeks parent stream to here before calling read(). */
    uoff_t parent_expected_offset;

    struct memarea *memarea;
    struct istream_snapshot *prev_snapshot;
    /* increased every time the stream is changed (e.g. seek, read).
       this way streams can check if their parent streams have been
       accessed behind them. */
    unsigned int access_counter;

    string_t *line_str; /* for i_stream_next_line() if w_buffer == NULL */
    bool line_crlf:1;
    bool return_nolf_line:1;
    bool stream_size_passthrough:1; /* stream is parent's size */
    bool nonpersistent_buffers:1;
};

struct istream_snapshot {
    struct istream_snapshot *prev_snapshot;
    struct memarea *old_memarea;
};

struct istream * ATTR_NOWARN_UNUSED_RESULT
i_stream_create(struct istream_private *stream, struct istream *parent, int fd)
    ATTR_NULL(2);
/* Initialize parent lazily after i_stream_create() has already been called. */
void i_stream_init_parent(struct istream_private *_stream,
              struct istream *parent);

void i_stream_compress(struct istream_private *stream);
void i_stream_grow_buffer(struct istream_private *stream, size_t bytes);
bool ATTR_NOWARN_UNUSED_RESULT
i_stream_try_alloc(struct istream_private *stream,
           size_t wanted_size, size_t *size_r);
void *i_stream_alloc(struct istream_private *stream, size_t size);
/* Free memory allocated by i_stream_*alloc() */
void i_stream_free_buffer(struct istream_private *stream);
ssize_t i_stream_read_copy_from_parent(struct istream *istream);
void i_stream_default_seek_nonseekable(struct istream_private *stream,
                       uoff_t v_offset, bool mark);

/* Default snapshot handling: use memarea if it exists, otherwise snapshot
   parent stream. */
struct istream_snapshot *
i_stream_default_snapshot(struct istream_private *stream,
              struct istream_snapshot *prev_snapshot);
void i_stream_snapshot_free(struct istream_snapshot **snapshot);

void i_stream_set_io(struct istream *stream, struct io *io);
void i_stream_unset_io(struct istream *stream, struct io *io);

#endif