diff options
Diffstat (limited to 'ctdb/common')
| -rw-r--r-- | ctdb/common/line.c | 145 | ||||
| -rw-r--r-- | ctdb/common/line.h | 62 |
2 files changed, 207 insertions, 0 deletions
diff --git a/ctdb/common/line.c b/ctdb/common/line.c new file mode 100644 index 00000000000..c4c6726875b --- /dev/null +++ b/ctdb/common/line.c @@ -0,0 +1,145 @@ +/* + Line based I/O over fds + + Copyright (C) Amitay Isaacs 2018 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ + +#include "replace.h" + +#include <talloc.h> + +#include "lib/util/sys_rw.h" + +#include "common/line.h" + +struct line_read_state { + line_process_fn_t callback; + void *private_data; + char *buf; + size_t hint, len, offset; + int num_lines; +}; + +static bool line_read_one(char *buf, size_t start, size_t len, size_t *pos) +{ + size_t i; + + for (i=start; i<len; i++) { + if (buf[i] == '\n' || buf[i] == '\0') { + *pos = i; + return true; + } + } + + return false; +} + +static int line_read_process(struct line_read_state *state) +{ + size_t start = 0; + size_t pos = 0; + + while (1) { + int ret; + bool ok; + + ok = line_read_one(state->buf, start, state->offset, &pos); + if (! ok) { + break; + } + + state->buf[pos] = '\0'; + state->num_lines += 1; + + ret = state->callback(state->buf + start, state->private_data); + if (ret != 0) { + return ret; + } + + start = pos+1; + } + + if (pos > 0) { + if (pos+1 < state->offset) { + memmove(state->buf, + state->buf + pos+1, + state->offset - (pos+1)); + } + state->offset -= (pos+1); + } + + return 0; +} + +int line_read(int fd, + size_t length, + TALLOC_CTX *mem_ctx, + line_process_fn_t callback, + void *private_data, + int *num_lines) +{ + struct line_read_state state; + + if (length < 32) { + length = 32; + } + + state = (struct line_read_state) { + .callback = callback, + .private_data = private_data, + .hint = length, + }; + + while (1) { + ssize_t n; + int ret; + + if (state.offset == state.len) { + state.len += state.hint; + state.buf = talloc_realloc_size(mem_ctx, + state.buf, + state.len); + if (state.buf == NULL) { + return ENOMEM; + } + } + + n = sys_read(fd, + state.buf + state.offset, + state.len - state.offset); + if (n < 0) { + return errno; + } + if (n == 0) { + break; + } + + state.offset += n; + + ret = line_read_process(&state); + if (ret != 0) { + if (num_lines != NULL) { + *num_lines = state.num_lines; + } + return ret; + } + } + + if (num_lines != NULL) { + *num_lines = state.num_lines; + } + return 0; +} diff --git a/ctdb/common/line.h b/ctdb/common/line.h new file mode 100644 index 00000000000..6b67f1e92e1 --- /dev/null +++ b/ctdb/common/line.h @@ -0,0 +1,62 @@ +/* + Line based I/O over fds + + Copyright (C) Amitay Isaacs 2018 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef __CTDB_LINE_H__ +#define __CTDB_LINE_H__ + +#include <talloc.h> + +/** + * @file line.h + * + * @brief Line based I/O over pipes and sockets + */ + +/** + * @brief The callback routine called to process a line + * + * @param[in] line The line read + * @param[in] private_data Private data for callback + * @return 0 to continue processing lines, non-zero to stop reading + */ +typedef int (*line_process_fn_t)(char *line, void *private_data); + +/** + * @brief Read a line (terminated by \n or \0) + * + * If there is any read error on fd, then errno will be returned. + * If callback function returns a non-zero value, then that value will be + * returned. + * + * @param[in] fd The file descriptor + * @param[in] length The expected length of a line (this is only a hint) + * @param[in] mem_ctx Talloc memory context + * @param[in] callback Callback function called when a line is read + * @param[in] private_data Private data for callback + * @param[out] num_lines Number of lines read so far + * @return 0 on on success, errno on failure + */ +int line_read(int fd, + size_t length, + TALLOC_CTX *mem_ctx, + line_process_fn_t callback, + void *private_data, + int *num_lines); + +#endif /* __CTDB_LINE_H__ */ |