diff options
author | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2023-06-09 20:03:53 +0200 |
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committer | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2023-06-09 20:03:53 +0200 |
commit | 605fd3e3a2656438dc0283699fc4a4b44b8b71db (patch) | |
tree | c5f8fdc27315df401a2fbb17c1e5b7ba267160f3 /lib | |
parent | 115ba7e0830a00a7b0bce5887c8ffeba78e3ab53 (diff) |
libtar: overhaul buffer management in istream_t wrapper
As soon as we no longer have any data to read, unlock/drop the
parent iterator_t object. Also, make sure we get the buffer
count right, not all data might have been consumed yet when
precache is called. Remove the precache/read loop in the non-sparse
case, we have already established that there is data available. If
it is insufficient, the user will simply call precache again once
it's used up, which istream_get_buffered_data forwards to a precache
call in the underlying stream.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/tar/src/iterator.c | 89 |
1 files changed, 44 insertions, 45 deletions
diff --git a/lib/tar/src/iterator.c b/lib/tar/src/iterator.c index 442ddeb..66b5dfc 100644 --- a/lib/tar/src/iterator.c +++ b/lib/tar/src/iterator.c @@ -38,8 +38,8 @@ typedef struct { istream_t base; tar_iterator_t *parent; + int state; - bool eof; sqfs_u8 buffer[4096]; } tar_istream_t; @@ -76,6 +76,21 @@ static bool is_sparse_region(const tar_iterator_t *tar, sqfs_u64 *count) /*****************************************************************************/ +static void drop_parent(tar_istream_t *tar, int state) +{ + if (tar->parent != NULL) { + tar->parent->locked = false; + tar->parent = sqfs_drop(tar->parent); + + if (state != 0 && tar->parent->state == 0) + tar->parent->state = state; + } + + ((istream_t *)tar)->buffer_used = 0; + ((istream_t *)tar)->buffer = tar->buffer; + tar->state = state; +} + static const char *strm_get_filename(istream_t *strm) { return ((tar_istream_t *)strm)->parent->current.name; @@ -86,18 +101,21 @@ static int strm_precache(istream_t *strm) tar_istream_t *tar = (tar_istream_t *)strm; sqfs_u64 diff; - if (tar->eof) - goto out_eof; + if (tar->parent == NULL) + return tar->state; + + diff = (tar->parent->last_chunk - strm->buffer_used); + if (diff == 0 && strm->buffer_used > 0) + return tar->state; if (!tar->parent->last_sparse) { - int ret = istream_advance_buffer(tar->parent->stream, - tar->parent->last_chunk); + int ret = istream_advance_buffer(tar->parent->stream, diff); if (ret != 0) return ret; - tar->parent->record_size -= tar->parent->last_chunk; + tar->parent->record_size -= diff; } - tar->parent->offset += tar->parent->last_chunk; + tar->parent->offset += diff; if (tar->parent->offset >= tar->parent->file_size) goto out_eof; @@ -106,60 +124,41 @@ static int strm_precache(istream_t *strm) goto out_eof; if (tar->parent->last_sparse) { - if (diff > sizeof(tar->buffer)) - diff = sizeof(tar->buffer); - strm->buffer = tar->buffer; - memset(tar->buffer, 0, diff); + strm->buffer_used = (diff <= sizeof(tar->buffer)) ? + diff : sizeof(tar->buffer); } else { - const sqfs_u8 *ptr; size_t avail; int ret; - for (int i = 0; i < 2; ++i) { - ret = istream_get_buffered_data(tar->parent->stream, - &ptr, &avail); - if (ret > 0) - goto fail_borked; - if (ret < 0) - goto fail_io; + ret = istream_get_buffered_data(tar->parent->stream, + &strm->buffer, &avail); + if (ret > 0) + goto fail_borked; + if (ret < 0) + goto fail_io; - if (diff <= avail) - break; - ret = istream_precache(tar->parent->stream); - if (ret) - goto fail_io; - } - - if (diff > avail) - diff = avail; - - strm->buffer = ptr; + strm->buffer_used = (diff <= avail) ? diff : avail; } - strm->buffer_used = diff; - tar->parent->last_chunk = diff; - return 0; -fail_borked: - tar->parent->state = SQFS_ERROR_CORRUPTED; - return -1; + tar->parent->last_chunk = strm->buffer_used; + return tar->state; fail_io: - tar->parent->state = SQFS_ERROR_IO; - return -1; + drop_parent(tar, SQFS_ERROR_IO); + return tar->state; +fail_borked: + drop_parent(tar, SQFS_ERROR_CORRUPTED); + return tar->state; out_eof: - tar->eof = true; - strm->buffer_used = 0; - strm->buffer = tar->buffer; - tar->parent->locked = false; - return tar->parent->state < 0 ? -1 : 0; + drop_parent(tar, 0); + return tar->state; } static void strm_destroy(sqfs_object_t *obj) { tar_istream_t *tar = (tar_istream_t *)obj; - tar->parent->locked = false; - sqfs_drop(tar->parent); + drop_parent(tar, 0); free(tar); } |