Mercurial > dovecot > core-2.2
view src/lib/istream-sized.c @ 21681:9ef9988619b7
lib: Added i_stream_create_sized_range()
This is just a small wrapper to i_stream_create_sized() to specify stream's
start offset.
author | Timo Sirainen <timo.sirainen@dovecot.fi> |
---|---|
date | Tue, 01 Nov 2016 14:47:05 +0200 |
parents | 2e2563132d5f |
children | 7945fd42b09f |
line wrap: on
line source
/* Copyright (c) 2003-2017 Dovecot authors, see the included COPYING file */ #include "lib.h" #include "istream-private.h" #include "istream-sized.h" struct sized_istream { struct istream_private istream; istream_sized_callback_t *error_callback; void *error_context; uoff_t size; bool failed; }; static void i_stream_sized_destroy(struct iostream_private *stream) { struct sized_istream *sstream = (struct sized_istream *)stream; uoff_t v_offset; v_offset = sstream->istream.parent_start_offset + sstream->istream.istream.v_offset; if (sstream->istream.parent->seekable || v_offset > sstream->istream.parent->v_offset) { /* get to same position in parent stream */ i_stream_seek(sstream->istream.parent, v_offset); } i_stream_unref(&sstream->istream.parent); } static const char * i_stream_create_sized_default_error_callback( const struct istream_sized_error_data *data, void *context ATTR_UNUSED) { if (data->v_offset + data->new_bytes < data->wanted_size) { return t_strdup_printf("Stream is smaller than expected " "(%"PRIuUOFF_T" < %"PRIuUOFF_T")", data->v_offset + data->new_bytes, data->wanted_size); } else { return t_strdup_printf("Stream is larger than expected " "(%"PRIuUOFF_T" > %"PRIuUOFF_T", eof=%d)", data->v_offset + data->new_bytes, data->wanted_size, data->eof); } } static ssize_t i_stream_sized_read(struct istream_private *stream) { struct sized_istream *sstream = (struct sized_istream *)stream; struct istream_sized_error_data data; const char *error; uoff_t left; ssize_t ret; size_t pos; if (sstream->failed) { /* avoid duplicate errors */ stream->istream.stream_errno = EINVAL; return -1; } if (stream->istream.v_offset + (stream->pos - stream->skip) >= sstream->size) { stream->istream.eof = TRUE; return -1; } i_stream_seek(stream->parent, sstream->istream.parent_start_offset + stream->istream.v_offset); stream->pos -= stream->skip; stream->skip = 0; stream->buffer = i_stream_get_data(stream->parent, &pos); if (pos > stream->pos) ret = 0; else do { if ((ret = i_stream_read(stream->parent)) == -2) return -2; stream->istream.stream_errno = stream->parent->stream_errno; stream->istream.eof = stream->parent->eof; stream->buffer = i_stream_get_data(stream->parent, &pos); } while (pos <= stream->pos && ret > 0); i_zero(&data); data.v_offset = stream->istream.v_offset; data.new_bytes = pos; data.wanted_size = sstream->size; data.eof = stream->istream.eof; left = sstream->size - stream->istream.v_offset; if (pos == left) stream->istream.eof = TRUE; else if (pos > left) { error = sstream->error_callback(&data, sstream->error_context); io_stream_set_error(&stream->iostream, "%s", error); i_error("read(%s) failed: %s", i_stream_get_name(stream->parent), stream->iostream.error); pos = left; stream->istream.eof = TRUE; stream->istream.stream_errno = EINVAL; sstream->failed = TRUE; return -1; } else if (!stream->istream.eof) { /* still more to read */ } else if (stream->istream.stream_errno == ENOENT) { /* lost the file */ } else { error = sstream->error_callback(&data, sstream->error_context); io_stream_set_error(&stream->iostream, "%s", error); i_error("read(%s) failed: %s", i_stream_get_name(stream->parent), stream->iostream.error); stream->istream.stream_errno = EINVAL; } ret = pos > stream->pos ? (ssize_t)(pos - stream->pos) : (ret == 0 ? 0 : -1); stream->pos = pos; i_assert(ret != -1 || stream->istream.eof || stream->istream.stream_errno != 0); return ret; } static int i_stream_sized_stat(struct istream_private *stream, bool exact ATTR_UNUSED) { struct sized_istream *sstream = (struct sized_istream *)stream; const struct stat *st; /* parent stream may be base64-decoder. don't waste time decoding the entire stream, since we already know what the size is supposed to be. */ if (i_stream_stat(stream->parent, FALSE, &st) < 0) { stream->istream.stream_errno = stream->parent->stream_errno; return -1; } stream->statbuf = *st; stream->statbuf.st_size = sstream->size; return 0; } static struct sized_istream * i_stream_create_sized_common(struct istream *input, uoff_t size) { struct sized_istream *sstream; sstream = i_new(struct sized_istream, 1); sstream->size = size; sstream->istream.max_buffer_size = input->real_stream->max_buffer_size; sstream->istream.iostream.destroy = i_stream_sized_destroy; sstream->istream.read = i_stream_sized_read; sstream->istream.stat = i_stream_sized_stat; sstream->istream.istream.readable_fd = input->readable_fd; sstream->istream.istream.blocking = input->blocking; sstream->istream.istream.seekable = input->seekable; (void)i_stream_create(&sstream->istream, input, i_stream_get_fd(input)); return sstream; } struct istream *i_stream_create_sized(struct istream *input, uoff_t size) { struct sized_istream *sstream; sstream = i_stream_create_sized_common(input, size); sstream->error_callback = i_stream_create_sized_default_error_callback; sstream->error_context = sstream; return &sstream->istream.istream; } struct istream *i_stream_create_sized_range(struct istream *input, uoff_t offset, uoff_t size) { uoff_t orig_offset = input->v_offset; struct istream *ret; input->v_offset = offset; ret = i_stream_create_sized(input, size); input->v_offset = orig_offset; return ret; } #undef i_stream_create_sized_with_callback struct istream * i_stream_create_sized_with_callback(struct istream *input, uoff_t size, istream_sized_callback_t *error_callback, void *context) { struct sized_istream *sstream; sstream = i_stream_create_sized_common(input, size); sstream->error_callback = error_callback; sstream->error_context = context; return &sstream->istream.istream; }