[v2,03/10] reftable/basics: provide new `reftable_buf` interface

Message ID	0ddc8c0c896a006e4cc094390125efcec0b3cdff.1728910727.git.ps@pks.im (mailing list archive)
State	Superseded
Headers	show Received: from fout-a3-smtp.messagingengine.com (fout-a3-smtp.messagingengine.com [103.168.172.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6009819CD0E for <git@vger.kernel.org>; Mon, 14 Oct 2024 13:02:32 +0000 (UTC) Feedback-ID: i197146af:Fastmail Date: Mon, 14 Oct 2024 15:02:24 +0200 From: Patrick Steinhardt <ps@pks.im> To: git@vger.kernel.org Cc: Edward Thomson <ethomson@edwardthomson.com>, karthik nayak <karthik.188@gmail.com> Subject: [PATCH v2 03/10] reftable/basics: provide new `reftable_buf` interface Message-ID: <0ddc8c0c896a006e4cc094390125efcec0b3cdff.1728910727.git.ps@pks.im> References: <cover.1728629612.git.ps@pks.im> <cover.1728910726.git.ps@pks.im> Precedence: bulk MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <cover.1728910726.git.ps@pks.im>
Series	reftable: stop using `struct strbuf` \| expand [v2,00/10] reftable: stop using `struct strbuf` [v2,01/10] reftable: stop using `strbuf_addbuf()` [v2,02/10] reftable: stop using `strbuf_addf()` [v2,03/10] reftable/basics: provide new `reftable_buf` interface [v2,04/10] reftable: convert from `strbuf` to `reftable_buf` [v2,05/10] reftable/blocksource: adapt interface name [v2,06/10] t/unit-tests: check for `reftable_buf` allocation errors [v2,07/10] reftable/stack: adapt `format_name()` to handle allocation failures [v2,08/10] reftable/record: adapt `reftable_record_key()` to handle allocation failures [v2,09/10] reftable/stack: adapt `stack_filename()` to handle allocation failures [v2,10/10] reftable: handle trivial `reftable_buf` errors

diff --git a/reftable/basics.c b/reftable/basics.c index 9a949e5cf80..65ad761da0b 100644 --- a/reftable/basics.c +++ b/reftable/basics.c @@ -9,6 +9,7 @@ license that can be found in the LICENSE file or at #define REFTABLE_ALLOW_BANNED_ALLOCATORS #include "basics.h" #include "reftable-basics.h" +#include "reftable-error.h" static void *(*reftable_malloc_ptr)(size_t sz); static void *(*reftable_realloc_ptr)(void *, size_t); @@ -69,6 +70,79 @@ void reftable_set_alloc(void *(*malloc)(size_t), reftable_free_ptr = free; } +void reftable_buf_init(struct reftable_buf *buf) +{ + struct reftable_buf empty = REFTABLE_BUF_INIT; + *buf = empty; +} + +void reftable_buf_release(struct reftable_buf *buf) +{ + reftable_free(buf->buf); + reftable_buf_init(buf); +} + +void reftable_buf_reset(struct reftable_buf *buf) +{ + if (buf->alloc) { + buf->len = 0; + buf->buf[0] = '\0'; + } +} + +int reftable_buf_setlen(struct reftable_buf *buf, size_t len) +{ + if (len > buf->len) + return -1; + if (len == buf->len) + return 0; + buf->buf[len] = '\0'; + buf->len = len; + return 0; +} + +int reftable_buf_cmp(const struct reftable_buf *a, const struct reftable_buf *b) +{ + size_t len = a->len < b->len ? a->len : b->len; + if (len) { + int cmp = memcmp(a->buf, b->buf, len); + if (cmp) + return cmp; + } + return a->len < b->len ? -1 : a->len != b->len; +} + +int reftable_buf_add(struct reftable_buf *buf, const void *data, size_t len) +{ + size_t newlen = buf->len + len; + + if (newlen + 1 > buf->alloc) { + char *reallocated = buf->buf; + REFTABLE_ALLOC_GROW(reallocated, newlen + 1, buf->alloc); + if (!reallocated) + return REFTABLE_OUT_OF_MEMORY_ERROR; + buf->buf = reallocated; + } + + memcpy(buf->buf + buf->len, data, len); + buf->buf[newlen] = '\0'; + buf->len = newlen; + + return 0; +} + +int reftable_buf_addstr(struct reftable_buf *buf, const char *s) +{ + return reftable_buf_add(buf, s, strlen(s)); +} + +char *reftable_buf_detach(struct reftable_buf *buf) +{ + char *result = buf->buf; + reftable_buf_init(buf); + return result; +} + void put_be24(uint8_t *out, uint32_t i) { out[0] = (uint8_t)((i >> 16) & 0xff); diff --git a/reftable/basics.h b/reftable/basics.h index 4c9ef0fe6c5..bd33c34deae 100644 --- a/reftable/basics.h +++ b/reftable/basics.h @@ -16,6 +16,62 @@ license that can be found in the LICENSE file or at #include "system.h" #include "reftable-basics.h" +struct reftable_buf { + size_t alloc; + size_t len; + char *buf; +}; +#define REFTABLE_BUF_INIT { 0 } + +/* + * Initialize the buffer such that it is ready for use. This is equivalent to + * using REFTABLE_BUF_INIT for stack-allocated variables. + */ +void reftable_buf_init(struct reftable_buf *buf); + +/* + * Release memory associated with the buffer. The buffer is reinitialized such + * that it can be reused for subsequent operations. + */ +void reftable_buf_release(struct reftable_buf *buf); + +/* + * Reset the buffer such that it is effectively empty, without releasing the + * memory that this structure holds on to. This is equivalent to calling + * `reftable_buf_setlen(buf, 0)`. + */ +void reftable_buf_reset(struct reftable_buf *buf); + +/* + * Trim the buffer to a shorter length by updating the `len` member and writing + * a NUL byte to `buf[len]`. Returns 0 on success, -1 when `len` points outside + * of the array. + */ +int reftable_buf_setlen(struct reftable_buf *buf, size_t len); + +/* + * Lexicographically compare the two buffers. Returns 0 when both buffers have + * the same contents, -1 when `a` is lexicographically smaller than `b`, and 1 + * otherwise. + */ +int reftable_buf_cmp(const struct reftable_buf *a, const struct reftable_buf *b); + +/* + * Add the given bytes to the buffer. Returns 0 on success, + * REFTABLE_OUT_OF_MEMORY_ERROR on allocation failure. + */ +int reftable_buf_add(struct reftable_buf *buf, const void *data, size_t len); + +/* Equivalent to `reftable_buf_add(buf, s, strlen(s))`. */ +int reftable_buf_addstr(struct reftable_buf *buf, const char *s); + +/* + * Detach the buffer from the structure such that the underlying memory is now + * owned by the caller. The buffer is reinitialized such that it can be reused + * for subsequent operations. + */ +char *reftable_buf_detach(struct reftable_buf *buf); + /* Bigendian en/decoding of integers */ void put_be24(uint8_t *out, uint32_t i);

[v2,03/10] reftable/basics: provide new `reftable_buf` interface

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