7c4c1cbc0b
The `block_source_read_block()` function and its implementations return an integer as a result that reflects either the number of bytes read, or an error. As such its return type, a signed integer, isn't wrong, but it doesn't give the reader a good hint what it actually returns. Refactor the function to return an `ssize_t` instead, which is typical for functions similar to read(3p) and should thus give readers a better signal what they can expect as a result. Adjust callers to better handle the returned value to avoid warnings with -Wsign-compare. One of these callers is `reader_get_block()`, whose return value is only ever used by its callers to figure out whether or not the read was successful. So instead of bubbling up the `ssize_t` there, too, we adapt it to only indicate success or errors. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
53 lines
1.4 KiB
C
53 lines
1.4 KiB
C
/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#ifndef REFTABLE_BLOCKSOURCE_H
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#define REFTABLE_BLOCKSOURCE_H
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#include <stdint.h>
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/* block_source is a generic wrapper for a seekable readable file.
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*/
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struct reftable_block_source {
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struct reftable_block_source_vtable *ops;
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void *arg;
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};
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/* a contiguous segment of bytes. It keeps track of its generating block_source
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* so it can return itself into the pool. */
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struct reftable_block {
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uint8_t *data;
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size_t len;
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struct reftable_block_source source;
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};
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/* block_source_vtable are the operations that make up block_source */
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struct reftable_block_source_vtable {
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/* returns the size of a block source */
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uint64_t (*size)(void *source);
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/*
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* Reads a segment from the block source. It is an error to read beyond
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* the end of the block.
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*/
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ssize_t (*read_block)(void *source, struct reftable_block *dest,
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uint64_t off, uint32_t size);
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/* mark the block as read; may return the data back to malloc */
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void (*return_block)(void *source, struct reftable_block *blockp);
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/* release all resources associated with the block source */
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void (*close)(void *source);
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};
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/* opens a file on the file system as a block_source */
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int reftable_block_source_from_file(struct reftable_block_source *block_src,
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const char *name);
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#endif
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