diff options
Diffstat (limited to 'utils.c')
| -rw-r--r-- | utils.c | 1168 |
1 files changed, 1168 insertions, 0 deletions
@@ -0,0 +1,1168 @@ +/* + * utils.c: utilities + * + * Copyright (c) 2014, Přemysl Janouch <p.janouch@gmail.com> + * All rights reserved. + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY + * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION + * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +#define _POSIX_C_SOURCE 199309L +#define _XOPEN_SOURCE 600 + +#include <stdio.h> +#include <stdlib.h> +#include <stdarg.h> +#include <stdbool.h> +#include <stdint.h> +#include <string.h> +#include <ctype.h> +#include <locale.h> +#include <errno.h> + +#include <unistd.h> +#include <sys/stat.h> +#include <libgen.h> +#include <iconv.h> + +#include <getopt.h> +#include "siphash.h" + +#if defined __GNUC__ +#define ATTRIBUTE_PRINTF(x, y) __attribute__ ((format (printf, x, y))) +#else // ! __GNUC__ +#define ATTRIBUTE_PRINTF(x, y) +#endif // ! __GNUC__ + +#if defined __GNUC__ && __GNUC__ >= 4 +#define ATTRIBUTE_SENTINEL __attribute__ ((sentinel)) +#else // ! __GNUC__ || __GNUC__ < 4 +#define ATTRIBUTE_SENTINEL +#endif // ! __GNUC__ || __GNUC__ < 4 + +#define N_ELEMENTS(a) (sizeof (a) / sizeof ((a)[0])) + +#define BLOCK_START do { +#define BLOCK_END } while (0) + +// --- Logging ----------------------------------------------------------------- + +static void +log_message_stdio (const char *quote, const char *fmt, va_list ap) +{ + FILE *stream = stderr; + + fputs (quote, stream); + vfprintf (stream, fmt, ap); + fputs ("\n", stream); +} + +static void +log_message (const char *quote, const char *fmt, ...) ATTRIBUTE_PRINTF (2, 3); + +static void +log_message (const char *quote, const char *fmt, ...) +{ + va_list ap; + va_start (ap, fmt); + log_message_stdio (quote, fmt, ap); + va_end (ap); +} + +// `fatal' is reserved for unexpected failures that would harm further operation + +// TODO: colors (probably copy over from stracepkg) +#define print_fatal(...) log_message ("fatal: ", __VA_ARGS__) +#define print_error(...) log_message ("error: ", __VA_ARGS__) +#define print_warning(...) log_message ("warning: ", __VA_ARGS__) +#define print_status(...) log_message ("-- ", __VA_ARGS__) + +#define exit_fatal(...) \ + BLOCK_START \ + print_fatal (__VA_ARGS__); \ + exit (EXIT_FAILURE); \ + BLOCK_END + +// --- Debugging and assertions ------------------------------------------------ + +// We should check everything that may possibly fail with at least a soft +// assertion, so that any causes for problems don't slip us by silently. +// +// `g_soft_asserts_are_deadly' may be useful while running inside a debugger. + +static bool g_debug_mode; ///< Debug messages are printed +static bool g_soft_asserts_are_deadly; ///< soft_assert() aborts as well + +#define print_debug(...) \ + BLOCK_START \ + if (g_debug_mode) \ + log_message ("debug: ", __VA_ARGS__); \ + BLOCK_END + +static void +assertion_failure_handler (bool is_fatal, const char *file, int line, + const char *function, const char *condition) +{ + if (is_fatal) + { + print_fatal ("assertion failed [%s:%d in function %s]: %s", + file, line, function, condition); + abort (); + } + else + print_debug ("assertion failed [%s:%d in function %s]: %s", + file, line, function, condition); +} + +#define soft_assert(condition) \ + ((condition) ? true : \ + (assertion_failure_handler (g_soft_asserts_are_deadly, \ + __FILE__, __LINE__, __func__, #condition), false)) + +#define hard_assert(condition) \ + ((condition) ? (void) 0 : \ + assertion_failure_handler (true, \ + __FILE__, __LINE__, __func__, #condition)) + +// --- Safe memory management -------------------------------------------------- + +// When a memory allocation fails and we need the memory, we're usually pretty +// much fucked. Use the non-prefixed versions when there's a legitimate +// worry that an unrealistic amount of memory may be requested for allocation. + +// XXX: it's not a good idea to use print_message() as it may want to allocate +// further memory for printf() and the output streams. That may fail. + +static void * +xmalloc (size_t n) +{ + void *p = malloc (n); + if (!p) + exit_fatal ("malloc: %s", strerror (errno)); + return p; +} + +static void * +xcalloc (size_t n, size_t m) +{ + void *p = calloc (n, m); + if (!p && n && m) + exit_fatal ("calloc: %s", strerror (errno)); + return p; +} + +static void * +xrealloc (void *o, size_t n) +{ + void *p = realloc (o, n); + if (!p && n) + exit_fatal ("realloc: %s", strerror (errno)); + return p; +} + +static void * +xreallocarray (void *o, size_t n, size_t m) +{ + if (m && n > SIZE_MAX / m) + { + errno = ENOMEM; + exit_fatal ("reallocarray: %s", strerror (errno)); + } + return xrealloc (o, n * m); +} + +static char * +xstrdup (const char *s) +{ + return strcpy (xmalloc (strlen (s) + 1), s); +} + +static char * +xstrndup (const char *s, size_t n) +{ + size_t size = strlen (s); + if (n > size) + n = size; + + char *copy = xmalloc (n + 1); + memcpy (copy, s, n); + copy[n] = '\0'; + return copy; +} + +// --- Double-linked list helpers ---------------------------------------------- + +#define LIST_HEADER(type) \ + struct type *next; \ + struct type *prev; + +#define LIST_PREPEND(head, link) \ + BLOCK_START \ + (link)->prev = NULL; \ + (link)->next = (head); \ + if ((link)->next) \ + (link)->next->prev = (link); \ + (head) = (link); \ + BLOCK_END + +#define LIST_UNLINK(head, link) \ + BLOCK_START \ + if ((link)->prev) \ + (link)->prev->next = (link)->next; \ + else \ + (head) = (link)->next; \ + if ((link)->next) \ + (link)->next->prev = (link)->prev; \ + BLOCK_END + +#define LIST_APPEND_WITH_TAIL(head, tail, link) \ + BLOCK_START \ + (link)->prev = (tail); \ + (link)->next = NULL; \ + if ((link)->prev) \ + (link)->prev->next = (link); \ + else \ + (head) = (link); \ + (tail) = (link); \ + BLOCK_END + +#define LIST_UNLINK_WITH_TAIL(head, tail, link) \ + BLOCK_START \ + if ((tail) == (link)) \ + (tail) = (link)->prev; \ + LIST_UNLINK ((head), (link)); \ + BLOCK_END + +// --- Dynamically allocated string array -------------------------------------- + +struct str_vector +{ + char **vector; + size_t len; + size_t alloc; +}; + +static void +str_vector_init (struct str_vector *self) +{ + self->alloc = 4; + self->len = 0; + self->vector = xcalloc (sizeof *self->vector, self->alloc); +} + +static void +str_vector_free (struct str_vector *self) +{ + unsigned i; + for (i = 0; i < self->len; i++) + free (self->vector[i]); + + free (self->vector); + self->vector = NULL; +} + +static void +str_vector_add_owned (struct str_vector *self, char *s) +{ + self->vector[self->len] = s; + if (++self->len >= self->alloc) + self->vector = xreallocarray (self->vector, + sizeof *self->vector, (self->alloc <<= 1)); + self->vector[self->len] = NULL; +} + +static void +str_vector_add (struct str_vector *self, const char *s) +{ + str_vector_add_owned (self, xstrdup (s)); +} + +// --- Dynamically allocated strings ------------------------------------------- + +// Basically a string builder to abstract away manual memory management. + +struct str +{ + char *str; ///< String data, null terminated + size_t alloc; ///< How many bytes are allocated + size_t len; ///< How long the string actually is +}; + +static void +str_init (struct str *self) +{ + self->alloc = 16; + self->len = 0; + self->str = strcpy (xmalloc (self->alloc), ""); +} + +static void +str_free (struct str *self) +{ + free (self->str); + self->str = NULL; + self->alloc = 0; + self->len = 0; +} + +static void +str_reset (struct str *self) +{ + str_free (self); + str_init (self); +} + +static char * +str_steal (struct str *self) +{ + char *str = self->str; + self->str = NULL; + str_free (self); + return str; +} + +static void +str_ensure_space (struct str *self, size_t n) +{ + // We allocate at least one more byte for the terminating null character + size_t new_alloc = self->alloc; + while (new_alloc <= self->len + n) + new_alloc <<= 1; + if (new_alloc != self->alloc) + self->str = xrealloc (self->str, (self->alloc = new_alloc)); +} + +static void +str_append_data (struct str *self, const void *data, size_t n) +{ + str_ensure_space (self, n); + memcpy (self->str + self->len, data, n); + self->len += n; + self->str[self->len] = '\0'; +} + +static void +str_append_c (struct str *self, char c) +{ + str_append_data (self, &c, 1); +} + +static void +str_append (struct str *self, const char *s) +{ + str_append_data (self, s, strlen (s)); +} + +static void +str_append_str (struct str *self, const struct str *another) +{ + str_append_data (self, another->str, another->len); +} + +static int +str_append_vprintf (struct str *self, const char *fmt, va_list va) +{ + va_list ap; + int size; + + va_copy (ap, va); + size = vsnprintf (NULL, 0, fmt, ap); + va_end (ap); + + if (size < 0) + return -1; + + va_copy (ap, va); + str_ensure_space (self, size); + size = vsnprintf (self->str + self->len, self->alloc - self->len, fmt, ap); + va_end (ap); + + if (size > 0) + self->len += size; + + return size; +} + +static int +str_append_printf (struct str *self, const char *fmt, ...) + ATTRIBUTE_PRINTF (2, 3); + +static int +str_append_printf (struct str *self, const char *fmt, ...) +{ + va_list ap; + + va_start (ap, fmt); + int size = str_append_vprintf (self, fmt, ap); + va_end (ap); + return size; +} + +// --- Errors ------------------------------------------------------------------ + +// Error reporting utilities. Inspired by GError, only much simpler. + +struct error +{ + char *message; ///< Textual description of the event +}; + +static void +error_set (struct error **e, const char *message, ...) ATTRIBUTE_PRINTF (2, 3); + +static void +error_set (struct error **e, const char *message, ...) +{ + if (!e) + return; + + va_list ap; + va_start (ap, message); + int size = vsnprintf (NULL, 0, message, ap); + va_end (ap); + + hard_assert (size >= 0); + + struct error *tmp = xmalloc (sizeof *tmp); + tmp->message = xmalloc (size + 1); + + va_start (ap, message); + size = vsnprintf (tmp->message, size + 1, message, ap); + va_end (ap); + + hard_assert (size >= 0); + + soft_assert (*e == NULL); + *e = tmp; +} + +static void +error_free (struct error *e) +{ + free (e->message); + free (e); +} + +// --- String hash map --------------------------------------------------------- + +// The most basic <string, managed pointer> map (or associative array). + +struct str_map_link +{ + LIST_HEADER (str_map_link) + + void *data; ///< Payload + size_t key_length; ///< Length of the key without '\0' + char key[]; ///< The key for this link +}; + +struct str_map +{ + struct str_map_link **map; ///< The hash table data itself + size_t alloc; ///< Number of allocated entries + size_t len; ///< Number of entries in the table + void (*free) (void *); ///< Callback to destruct the payload + + /// Callback that transforms all key values for storage and comparison; + /// has to behave exactly like strxfrm(). + size_t (*key_xfrm) (char *dest, const char *src, size_t n); +}; + +#define STR_MAP_MIN_ALLOC 16 + +typedef void (*str_map_free_fn) (void *); + +static void +str_map_init (struct str_map *self) +{ + self->alloc = STR_MAP_MIN_ALLOC; + self->len = 0; + self->free = NULL; + self->key_xfrm = NULL; + self->map = xcalloc (self->alloc, sizeof *self->map); +} + +static void +str_map_free (struct str_map *self) +{ + struct str_map_link **iter, **end = self->map + self->alloc; + struct str_map_link *link, *tmp; + + for (iter = self->map; iter < end; iter++) + for (link = *iter; link; link = tmp) + { + tmp = link->next; + if (self->free) + self->free (link->data); + free (link); + } + + free (self->map); + self->map = NULL; +} + +static uint64_t +str_map_hash (const char *s, size_t len) +{ + static unsigned char key[16] = "SipHash 2-4 key!"; + return siphash (key, (const void *) s, len); +} + +static uint64_t +str_map_pos (struct str_map *self, const char *s) +{ + size_t mask = self->alloc - 1; + return str_map_hash (s, strlen (s)) & mask; +} + +static uint64_t +str_map_link_hash (struct str_map_link *self) +{ + return str_map_hash (self->key, self->key_length); +} + +static void +str_map_resize (struct str_map *self, size_t new_size) +{ + struct str_map_link **old_map = self->map; + size_t i, old_size = self->alloc; + + // Only powers of two, so that we don't need to compute the modulo + hard_assert ((new_size & (new_size - 1)) == 0); + size_t mask = new_size - 1; + + self->alloc = new_size; + self->map = xcalloc (self->alloc, sizeof *self->map); + for (i = 0; i < old_size; i++) + { + struct str_map_link *iter = old_map[i], *next_iter; + while (iter) + { + next_iter = iter->next; + uint64_t pos = str_map_link_hash (iter) & mask; + LIST_PREPEND (self->map[pos], iter); + iter = next_iter; + } + } + + free (old_map); +} + +static void +str_map_set_real (struct str_map *self, const char *key, void *value) +{ + uint64_t pos = str_map_pos (self, key); + struct str_map_link *iter = self->map[pos]; + for (; iter; iter = iter->next) + { + if (strcmp (key, iter->key)) + continue; + + // Storing the same data doesn't destroy it + if (self->free && value != iter->data) + self->free (iter->data); + + if (value) + { + iter->data = value; + return; + } + + LIST_UNLINK (self->map[pos], iter); + free (iter); + self->len--; + + // The array should be at least 1/4 full + if (self->alloc >= (STR_MAP_MIN_ALLOC << 2) + && self->len < (self->alloc >> 2)) + str_map_resize (self, self->alloc >> 2); + return; + } + + if (!value) + return; + + if (self->len >= self->alloc) + { + str_map_resize (self, self->alloc << 1); + pos = str_map_pos (self, key); + } + + // Link in a new element for the given <key, value> pair + size_t key_length = strlen (key); + struct str_map_link *link = xmalloc (sizeof *link + key_length + 1); + link->data = value; + link->key_length = key_length; + memcpy (link->key, key, key_length + 1); + + LIST_PREPEND (self->map[pos], link); + self->len++; +} + +static void +str_map_set (struct str_map *self, const char *key, void *value) +{ + if (!self->key_xfrm) + { + str_map_set_real (self, key, value); + return; + } + char tmp[self->key_xfrm (NULL, key, 0) + 1]; + self->key_xfrm (tmp, key, sizeof tmp); + str_map_set_real (self, tmp, value); +} + +static void * +str_map_find_real (struct str_map *self, const char *key) +{ + struct str_map_link *iter = self->map[str_map_pos (self, key)]; + for (; iter; iter = iter->next) + if (!strcmp (key, (const char *) iter + sizeof *iter)) + return iter->data; + return NULL; +} + +static void * +str_map_find (struct str_map *self, const char *key) +{ + if (!self->key_xfrm) + return str_map_find_real (self, key); + + char tmp[self->key_xfrm (NULL, key, 0) + 1]; + self->key_xfrm (tmp, key, sizeof tmp); + return str_map_find_real (self, tmp); +} + +// --- Utilities --------------------------------------------------------------- + +static void +split_str_ignore_empty (const char *s, char delimiter, struct str_vector *out) +{ + const char *begin = s, *end; + + while ((end = strchr (begin, delimiter))) + { + if (begin != end) + str_vector_add_owned (out, xstrndup (begin, end - begin)); + begin = ++end; + } + + if (*begin) + str_vector_add (out, begin); +} + +static char *xstrdup_printf (const char *format, ...) ATTRIBUTE_PRINTF (1, 2); + +static char * +xstrdup_printf (const char *format, ...) +{ + va_list ap; + va_start (ap, format); + int size = vsnprintf (NULL, 0, format, ap); + va_end (ap); + if (size < 0) + return NULL; + + char buf[size + 1]; + va_start (ap, format); + size = vsnprintf (buf, sizeof buf, format, ap); + va_end (ap); + if (size < 0) + return NULL; + + return xstrdup (buf); +} + +static char * +iconv_xstrdup (iconv_t conv, char *in, size_t in_len, size_t *out_len) +{ + char *buf, *buf_ptr; + size_t out_left, buf_alloc; + + buf = buf_ptr = xmalloc (out_left = buf_alloc = 64); + + char *in_ptr = in; + if (in_len == (size_t) -1) + in_len = strlen (in) + 1; + + while (iconv (conv, (char **) &in_ptr, &in_len, + (char **) &buf_ptr, &out_left) == (size_t) -1) + { + if (errno != E2BIG) + { + free (buf); + return NULL; + } + out_left += buf_alloc; + char *new_buf = xrealloc (buf, buf_alloc <<= 1); + buf_ptr += new_buf - buf; + buf = new_buf; + } + if (out_len) + *out_len = buf_alloc - out_left; + return buf; +} + +static bool +str_append_env_path (struct str *output, const char *var, bool only_absolute) +{ + const char *value = getenv (var); + + if (!value || (only_absolute && *value != '/')) + return false; + + str_append (output, value); + return true; +} + +static void +get_xdg_home_dir (struct str *output, const char *var, const char *def) +{ + str_reset (output); + if (!str_append_env_path (output, var, true)) + { + str_append_env_path (output, "HOME", false); + str_append_c (output, '/'); + str_append (output, def); + } +} + +static void +get_xdg_config_dirs (struct str_vector *out) +{ + struct str config_home; + str_init (&config_home); + get_xdg_home_dir (&config_home, "XDG_CONFIG_HOME", ".config"); + str_vector_add (out, config_home.str); + str_free (&config_home); + + const char *xdg_config_dirs; + if ((xdg_config_dirs = getenv ("XDG_CONFIG_DIRS"))) + split_str_ignore_empty (xdg_config_dirs, ':', out); +} + +static char * +resolve_config_filename (const char *filename) +{ + // Absolute path is absolute + if (*filename == '/') + return xstrdup (filename); + + struct str_vector paths; + str_vector_init (&paths); + get_xdg_config_dirs (&paths); + + struct str file; + str_init (&file); + + char *result = NULL; + for (unsigned i = 0; i < paths.len; i++) + { + // As per spec, relative paths are ignored + if (*paths.vector[i] != '/') + continue; + + str_reset (&file); + str_append_printf (&file, "%s/" PROGRAM_NAME "/%s", + paths.vector[i], filename); + + struct stat st; + if (!stat (file.str, &st)) + { + result = str_steal (&file); + break; + } + } + + str_vector_free (&paths); + str_free (&file); + return result; +} + +static bool +ensure_directory_existence (const char *path, struct error **e) +{ + struct stat st; + + if (stat (path, &st)) + { + if (mkdir (path, S_IRWXU | S_IRWXG | S_IRWXO)) + { + error_set (e, "cannot create directory `%s': %s", + path, strerror (errno)); + return false; + } + } + else if (!S_ISDIR (st.st_mode)) + { + error_set (e, "cannot create directory `%s': %s", + path, "file exists but is not a directory"); + return false; + } + return true; +} + +static bool +mkdir_with_parents (char *path, struct error **e) +{ + char *p = path; + + // XXX: This is prone to the TOCTTOU problem. The solution would be to + // rewrite the function using the {mkdir,fstat}at() functions from + // POSIX.1-2008, ideally returning a file descriptor to the open + // directory, with the current code as a fallback. Or to use chdir(). + while ((p = strchr (p + 1, '/'))) + { + *p = '\0'; + bool success = ensure_directory_existence (path, e); + *p = '/'; + + if (!success) + return false; + } + + return ensure_directory_existence (path, e); +} + +static bool +read_line (FILE *fp, struct str *s) +{ + int c; + bool at_end = true; + + str_reset (s); + while ((c = fgetc (fp)) != EOF) + { + at_end = false; + if (c == '\r') + continue; + if (c == '\n') + break; + str_append_c (s, c); + } + + return !at_end; +} + +// --- Configuration ----------------------------------------------------------- + +// The keys are stripped of surrounding whitespace, the values are not. + +struct config_item +{ + const char *key; + const char *default_value; + const char *description; +}; + +static void +load_config_defaults (struct str_map *config, const struct config_item *table) +{ + for (; table->key != NULL; table++) + if (table->default_value) + str_map_set (config, table->key, xstrdup (table->default_value)); + else + str_map_set (config, table->key, NULL); +} + +static bool +read_config_file (struct str_map *config, struct error **e) +{ + char *filename = resolve_config_filename (PROGRAM_NAME ".conf"); + if (!filename) + return true; + + FILE *fp = fopen (filename, "r"); + if (!fp) + { + error_set (e, "could not open `%s' for reading: %s", + filename, strerror (errno)); + free (filename); + return false; + } + + struct str line; + str_init (&line); + + bool errors = false; + for (unsigned line_no = 1; read_line (fp, &line); line_no++) + { + char *start = line.str; + if (*start == '#') + continue; + + while (isspace (*start)) + start++; + + char *end = strchr (start, '='); + if (end) + { + char *value = end + 1; + do + *end = '\0'; + while (isspace (*--end)); + + str_map_set (config, start, xstrdup (value)); + } + else if (*start) + { + error_set (e, "line %u in config: %s", line_no, "malformed input"); + errors = true; + break; + } + } + + str_free (&line); + fclose (fp); + free (filename); + return !errors; +} + +static char * +write_default_config (const char *filename, const char *prolog, + const struct config_item *table, struct error **e) +{ + struct str path, base; + + str_init (&path); + str_init (&base); + + if (filename) + { + char *tmp = xstrdup (filename); + str_append (&path, dirname (tmp)); + strcpy (tmp, filename); + str_append (&base, basename (tmp)); + free (tmp); + } + else + { + get_xdg_home_dir (&path, "XDG_CONFIG_HOME", ".config"); + str_append (&path, "/" PROGRAM_NAME); + str_append (&base, PROGRAM_NAME ".conf"); + } + + if (!mkdir_with_parents (path.str, e)) + goto error; + + str_append_c (&path, '/'); + str_append_str (&path, &base); + + FILE *fp = fopen (path.str, "w"); + if (!fp) + { + error_set (e, "could not open `%s' for writing: %s", + path.str, strerror (errno)); + goto error; + } + + if (prolog) + fputs (prolog, fp); + + errno = 0; + for (; table->key != NULL; table++) + { + fprintf (fp, "# %s\n", table->description); + if (table->default_value) + fprintf (fp, "%s=%s\n", table->key, table->default_value); + else + fprintf (fp, "#%s=\n", table->key); + } + fclose (fp); + if (errno) + { + error_set (e, "writing to `%s' failed: %s", path.str, strerror (errno)); + goto error; + } + + str_free (&base); + return str_steal (&path); + +error: + str_free (&base); + str_free (&path); + return NULL; + +} + +static void +call_write_default_config (const char *hint, const struct config_item *table) +{ + static const char *prolog = + "# " PROGRAM_NAME " " PROGRAM_VERSION " configuration file\n" + "#\n" + "# Relative paths are searched for in ${XDG_CONFIG_HOME:-~/.config}\n" + "# /" PROGRAM_NAME " as well as in $XDG_CONFIG_DIRS/" PROGRAM_NAME "\n" + "\n"; + + struct error *e = NULL; + char *filename = write_default_config (hint, prolog, table, &e); + if (!filename) + { + print_error ("%s", e->message); + error_free (e); + exit (EXIT_FAILURE); + } + print_status ("configuration written to `%s'", filename); + free (filename); +} + +// --- Option handler ---------------------------------------------------------- + +// Simple wrapper for the getopt_long API to make it easier to use and maintain. + +#define OPT_USAGE_ALIGNMENT_COLUMN 30 ///< Alignment for option descriptions + +enum +{ + OPT_OPTIONAL_ARG = (1 << 0), ///< The argument is optional + OPT_LONG_ONLY = (1 << 1) ///< Ignore the short name in opt_string +}; + +// All options need to have both a short name, and a long name. The short name +// is what is returned from opt_handler_get(). It is possible to define a value +// completely out of the character range combined with the OPT_LONG_ONLY flag. +// +// When `arg_hint' is defined, the option is assumed to have an argument. + +struct opt +{ + int short_name; ///< The single-letter name + const char *long_name; ///< The long name + const char *arg_hint; ///< Option argument hint + int flags; ///< Option flags + const char *description; ///< Option description +}; + +struct opt_handler +{ + int argc; ///< The number of program arguments + char **argv; ///< Program arguments + + const char *arg_hint; ///< Program arguments hint + const char *description; ///< Description of the program + + const struct opt *opts; ///< The list of options + size_t opts_len; ///< The length of the option array + + struct option *options; ///< The list of options for getopt + char *opt_string; ///< The `optstring' for getopt +}; + +static void +opt_handler_free (struct opt_handler *self) +{ + free (self->options); + free (self->opt_string); +} + +static void +opt_handler_init (struct opt_handler *self, int argc, char **argv, + const struct opt *opts, const char *arg_hint, const char *description) +{ + memset (self, 0, sizeof *self); + self->argc = argc; + self->argv = argv; + self->arg_hint = arg_hint; + self->description = description; + + size_t len = 0; + for (const struct opt *iter = opts; iter->long_name; iter++) + len++; + + self->opts = opts; + self->opts_len = len; + self->options = xcalloc (len + 1, sizeof *self->options); + + struct str opt_string; + str_init (&opt_string); + + for (size_t i = 0; i < len; i++) + { + const struct opt *opt = opts + i; + struct option *mapped = self->options + i; + + mapped->name = opt->long_name; + if (!opt->arg_hint) + mapped->has_arg = no_argument; + else if (opt->flags & OPT_OPTIONAL_ARG) + mapped->has_arg = optional_argument; + else + mapped->has_arg = required_argument; + mapped->val = opt->short_name; + + if (opt->flags & OPT_LONG_ONLY) + continue; + + str_append_c (&opt_string, opt->short_name); + if (opt->arg_hint) + { + str_append_c (&opt_string, ':'); + if (opt->flags & OPT_OPTIONAL_ARG) + str_append_c (&opt_string, ':'); + } + } + + self->opt_string = str_steal (&opt_string); +} + +static void +opt_handler_usage (struct opt_handler *self, FILE *stream) +{ + struct str usage; + str_init (&usage); + + str_append_printf (&usage, "Usage: %s [OPTION]... %s\n", + self->argv[0], self->arg_hint ? self->arg_hint : ""); + str_append_printf (&usage, "%s\n\n", self->description); + + for (size_t i = 0; i < self->opts_len; i++) + { + struct str row; + str_init (&row); + + const struct opt *opt = self->opts + i; + if (!(opt->flags & OPT_LONG_ONLY)) + str_append_printf (&row, " -%c, ", opt->short_name); + else + str_append (&row, " "); + str_append_printf (&row, "--%s", opt->long_name); + if (opt->arg_hint) + str_append_printf (&row, (opt->flags & OPT_OPTIONAL_ARG) + ? " [%s]" : " %s", opt->arg_hint); + + // TODO: keep the indent if there are multiple lines + if (row.len + 2 <= OPT_USAGE_ALIGNMENT_COLUMN) + { + str_append (&row, " "); + str_append_printf (&usage, "%-*s%s\n", + OPT_USAGE_ALIGNMENT_COLUMN, row.str, opt->description); + } + else + str_append_printf (&usage, "%s\n%-*s%s\n", row.str, + OPT_USAGE_ALIGNMENT_COLUMN, "", opt->description); + + str_free (&row); + } + + fputs (usage.str, stream); + str_free (&usage); +} + +static int +opt_handler_get (struct opt_handler *self) +{ + return getopt_long (self->argc, self->argv, + self->opt_string, self->options, NULL); +} |