1214aa841b
The reftable format is usually used with files for storage. However, we abstract away this using the blocksource data structure. This has two advantages: * log blocks are zlib compressed, and handling them is simplified if we can discard byte segments from within the block layer. * for unittests, it is useful to read and write in-memory. The blocksource allows us to abstract the data away from on-disk files. Signed-off-by: Han-Wen Nienhuys <hanwen@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
149 lines
3.0 KiB
C
149 lines
3.0 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 strbuf_return_block(void *b, struct reftable_block *dest)
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{
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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 strbuf_close(void *b)
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{
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}
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static int strbuf_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 strbuf *b = v;
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assert(off + size <= b->len);
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dest->data = reftable_calloc(size);
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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 strbuf_size(void *b)
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{
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return ((struct strbuf *)b)->len;
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}
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static struct reftable_block_source_vtable strbuf_vtable = {
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.size = &strbuf_size,
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.read_block = &strbuf_read_block,
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.return_block = &strbuf_return_block,
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.close = &strbuf_close,
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};
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void block_source_from_strbuf(struct reftable_block_source *bs,
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struct strbuf *buf)
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{
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assert(!bs->ops);
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bs->ops = &strbuf_vtable;
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bs->arg = buf;
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}
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static void malloc_return_block(void *b, struct reftable_block *dest)
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{
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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 struct reftable_block_source_vtable malloc_vtable = {
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.return_block = &malloc_return_block,
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};
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static struct reftable_block_source malloc_block_source_instance = {
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.ops = &malloc_vtable,
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};
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struct reftable_block_source malloc_block_source(void)
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{
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return malloc_block_source_instance;
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}
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struct file_block_source {
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int fd;
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uint64_t size;
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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, struct reftable_block *dest)
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{
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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 file_close(void *b)
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{
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int fd = ((struct file_block_source *)b)->fd;
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if (fd > 0) {
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close(fd);
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((struct file_block_source *)b)->fd = 0;
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}
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reftable_free(b);
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}
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static int 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 = reftable_malloc(size);
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if (pread(b->fd, dest->data, size, off) != size)
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return -1;
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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 stat st = { 0 };
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int err = 0;
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int fd = open(name, O_RDONLY);
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struct file_block_source *p = NULL;
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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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}
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return -1;
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}
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err = fstat(fd, &st);
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if (err < 0)
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return -1;
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p = reftable_calloc(sizeof(struct file_block_source));
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p->size = st.st_size;
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p->fd = fd;
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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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return 0;
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}
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