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>
140 lines
2.8 KiB
C
140 lines
2.8 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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#include "system.h"
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#include "basics.h"
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#include "blocksource.h"
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#include "reftable-blocksource.h"
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#include "reftable-error.h"
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static void reftable_buf_return_block(void *b UNUSED, struct reftable_block *dest)
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{
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if (dest->len)
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memset(dest->data, 0xff, dest->len);
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reftable_free(dest->data);
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}
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static void reftable_buf_close(void *b UNUSED)
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{
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}
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static ssize_t reftable_buf_read_block(void *v, struct reftable_block *dest,
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uint64_t off, uint32_t size)
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{
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struct reftable_buf *b = v;
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assert(off + size <= b->len);
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REFTABLE_CALLOC_ARRAY(dest->data, size);
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if (!dest->data)
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return -1;
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memcpy(dest->data, b->buf + off, size);
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dest->len = size;
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return size;
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}
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static uint64_t reftable_buf_size(void *b)
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{
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return ((struct reftable_buf *)b)->len;
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}
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static struct reftable_block_source_vtable reftable_buf_vtable = {
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.size = &reftable_buf_size,
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.read_block = &reftable_buf_read_block,
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.return_block = &reftable_buf_return_block,
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.close = &reftable_buf_close,
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};
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void block_source_from_buf(struct reftable_block_source *bs,
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struct reftable_buf *buf)
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{
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assert(!bs->ops);
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bs->ops = &reftable_buf_vtable;
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bs->arg = buf;
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}
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struct file_block_source {
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uint64_t size;
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unsigned char *data;
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};
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static uint64_t file_size(void *b)
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{
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return ((struct file_block_source *)b)->size;
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}
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static void file_return_block(void *b UNUSED, struct reftable_block *dest UNUSED)
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{
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}
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static void file_close(void *v)
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{
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struct file_block_source *b = v;
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munmap(b->data, b->size);
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reftable_free(b);
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}
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static ssize_t file_read_block(void *v, struct reftable_block *dest, uint64_t off,
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uint32_t size)
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{
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struct file_block_source *b = v;
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assert(off + size <= b->size);
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dest->data = b->data + off;
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dest->len = size;
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return size;
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}
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static struct reftable_block_source_vtable file_vtable = {
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.size = &file_size,
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.read_block = &file_read_block,
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.return_block = &file_return_block,
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.close = &file_close,
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};
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int reftable_block_source_from_file(struct reftable_block_source *bs,
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const char *name)
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{
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struct file_block_source *p;
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struct stat st;
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int fd, err;
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fd = open(name, O_RDONLY);
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if (fd < 0) {
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if (errno == ENOENT)
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return REFTABLE_NOT_EXIST_ERROR;
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err = -1;
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goto out;
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}
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if (fstat(fd, &st) < 0) {
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err = REFTABLE_IO_ERROR;
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goto out;
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}
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REFTABLE_CALLOC_ARRAY(p, 1);
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if (!p) {
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err = REFTABLE_OUT_OF_MEMORY_ERROR;
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goto out;
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}
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p->size = st.st_size;
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p->data = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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assert(!bs->ops);
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bs->ops = &file_vtable;
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bs->arg = p;
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err = 0;
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out:
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if (fd >= 0)
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close(fd);
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if (err < 0)
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reftable_free(p);
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return 0;
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}
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