git

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/*
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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 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 strbuf_close(void *b UNUSED)
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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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	REFTABLE_CALLOC_ARRAY(dest->data, 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 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 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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	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 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 = 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;
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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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		return -1;
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	}
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	if (fstat(fd, &st) < 0) {
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		close(fd);
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		return REFTABLE_IO_ERROR;
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	}
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	REFTABLE_CALLOC_ARRAY(p, 1);
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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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	close(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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