mirror of
https://github.com/git/git.git
synced 2024-12-03 06:53:53 +08:00
0283cd5161
strbuf_addf() has been reporting a negative return value of vsnprintf(3) as a bug sincef141bd804d
(Handle broken vsnprintf implementations in strbuf, 2007-11-13). Other functions copied that behavior:7b03c89ebd
(add xsnprintf helper function, 2015-09-24)5ef264dbdb
(strbuf.c: add `strbuf_insertf()` and `strbuf_vinsertf()`, 2019-02-25)8d25663d70
(mem-pool: add mem_pool_strfmt(), 2024-02-25) However, vsnprintf(3) can legitimately return a negative value if the formatted output would be longer than INT_MAX. Stop accusing it of being broken and just report the fact that formatting failed. Suggested-by: Jeff King <peff@peff.net> Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
219 lines
5.1 KiB
C
219 lines
5.1 KiB
C
/*
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* Memory Pool implementation logic.
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*/
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#include "git-compat-util.h"
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#include "mem-pool.h"
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#include "gettext.h"
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#define BLOCK_GROWTH_SIZE (1024 * 1024 - sizeof(struct mp_block))
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/*
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* The inner union is an approximation for C11's max_align_t, and the
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* struct + offsetof computes _Alignof. This can all just be replaced
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* with _Alignof(max_align_t) if/when C11 is part of the baseline.
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* Note that _Alignof(X) need not be the same as sizeof(X); it's only
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* required to be a (possibly trivial) factor. They are the same for
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* most architectures, but m68k for example has only 2-byte alignment
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* for its 4-byte and 8-byte types, so using sizeof would waste space.
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*
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* Add more types to the union if the current set is insufficient.
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*/
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struct git_max_alignment {
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char unalign;
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union {
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uintmax_t max_align_uintmax;
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void *max_align_pointer;
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} aligned;
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};
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#define GIT_MAX_ALIGNMENT offsetof(struct git_max_alignment, aligned)
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/*
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* Allocate a new mp_block and insert it after the block specified in
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* `insert_after`. If `insert_after` is NULL, then insert block at the
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* head of the linked list.
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*/
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static struct mp_block *mem_pool_alloc_block(struct mem_pool *pool,
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size_t block_alloc,
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struct mp_block *insert_after)
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{
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struct mp_block *p;
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pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
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p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
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p->next_free = (char *)p->space;
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p->end = p->next_free + block_alloc;
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if (insert_after) {
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p->next_block = insert_after->next_block;
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insert_after->next_block = p;
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} else {
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p->next_block = pool->mp_block;
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pool->mp_block = p;
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}
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return p;
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}
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void mem_pool_init(struct mem_pool *pool, size_t initial_size)
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{
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memset(pool, 0, sizeof(*pool));
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pool->block_alloc = BLOCK_GROWTH_SIZE;
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if (initial_size > 0)
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mem_pool_alloc_block(pool, initial_size, NULL);
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}
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void mem_pool_discard(struct mem_pool *pool, int invalidate_memory)
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{
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struct mp_block *block, *block_to_free;
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block = pool->mp_block;
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while (block)
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{
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block_to_free = block;
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block = block->next_block;
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if (invalidate_memory)
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memset(block_to_free->space, 0xDD, ((char *)block_to_free->end) - ((char *)block_to_free->space));
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free(block_to_free);
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}
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pool->mp_block = NULL;
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pool->pool_alloc = 0;
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}
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void *mem_pool_alloc(struct mem_pool *pool, size_t len)
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{
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struct mp_block *p = NULL;
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void *r;
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len = DIV_ROUND_UP(len, GIT_MAX_ALIGNMENT) * GIT_MAX_ALIGNMENT;
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if (pool->mp_block &&
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pool->mp_block->end - pool->mp_block->next_free >= len)
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p = pool->mp_block;
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if (!p) {
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if (len >= (pool->block_alloc / 2))
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p = mem_pool_alloc_block(pool, len, pool->mp_block);
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else
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p = mem_pool_alloc_block(pool, pool->block_alloc, NULL);
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}
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r = p->next_free;
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p->next_free += len;
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return r;
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}
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static char *mem_pool_strvfmt(struct mem_pool *pool, const char *fmt,
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va_list ap)
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{
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struct mp_block *block = pool->mp_block;
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char *next_free = block ? block->next_free : NULL;
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size_t available = block ? block->end - block->next_free : 0;
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va_list cp;
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int len, len2;
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size_t size;
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char *ret;
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va_copy(cp, ap);
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len = vsnprintf(next_free, available, fmt, cp);
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va_end(cp);
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if (len < 0)
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die(_("unable to format message: %s"), fmt);
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size = st_add(len, 1); /* 1 for NUL */
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ret = mem_pool_alloc(pool, size);
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/* Shortcut; relies on mem_pool_alloc() not touching buffer contents. */
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if (ret == next_free)
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return ret;
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len2 = vsnprintf(ret, size, fmt, ap);
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if (len2 != len)
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BUG("your vsnprintf is broken (returns inconsistent lengths)");
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return ret;
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}
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char *mem_pool_strfmt(struct mem_pool *pool, const char *fmt, ...)
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{
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va_list ap;
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char *ret;
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va_start(ap, fmt);
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ret = mem_pool_strvfmt(pool, fmt, ap);
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va_end(ap);
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return ret;
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}
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void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size)
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{
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size_t len = st_mult(count, size);
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void *r = mem_pool_alloc(pool, len);
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memset(r, 0, len);
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return r;
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}
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char *mem_pool_strdup(struct mem_pool *pool, const char *str)
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{
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size_t len = strlen(str) + 1;
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char *ret = mem_pool_alloc(pool, len);
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return memcpy(ret, str, len);
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}
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char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len)
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{
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char *p = memchr(str, '\0', len);
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size_t actual_len = (p ? p - str : len);
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char *ret = mem_pool_alloc(pool, actual_len+1);
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ret[actual_len] = '\0';
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return memcpy(ret, str, actual_len);
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}
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int mem_pool_contains(struct mem_pool *pool, void *mem)
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{
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struct mp_block *p;
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/* Check if memory is allocated in a block */
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for (p = pool->mp_block; p; p = p->next_block)
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if ((mem >= ((void *)p->space)) &&
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(mem < ((void *)p->end)))
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return 1;
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return 0;
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}
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void mem_pool_combine(struct mem_pool *dst, struct mem_pool *src)
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{
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struct mp_block *p;
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/* Append the blocks from src to dst */
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if (dst->mp_block && src->mp_block) {
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/*
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* src and dst have blocks, append
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* blocks from src to dst.
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*/
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p = dst->mp_block;
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while (p->next_block)
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p = p->next_block;
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p->next_block = src->mp_block;
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} else if (src->mp_block) {
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/*
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* src has blocks, dst is empty.
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*/
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dst->mp_block = src->mp_block;
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} else {
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/* src is empty, nothing to do. */
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}
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dst->pool_alloc += src->pool_alloc;
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src->pool_alloc = 0;
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src->mp_block = NULL;
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}
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