1#pragma once
2
3// This module implements a configuration parser. Clients can query the
4// contents of a configuration file through the interface provided here.
5// The current implementation is read-only; mutations are only kept in
6// memory. This parser supports the INI file format.
7
8// Implementation notes:
9// - Key/value pairs that are not within a section are assumed to be under
10//   the |CONFIG_DEFAULT_SECTION| section.
11// - Multiple sections with the same name will be merged as if they were in
12//   a single section.
13// - Empty sections with no key/value pairs will be treated as if they do
14//   not exist. In other words, |config_has_section| will return false for
15//   empty sections.
16// - Duplicate keys in a section will overwrite previous values.
17// - All strings are case sensitive.
18
19#include <stdbool.h>
20
21// The default section name to use if a key/value pair is not defined within
22// a section.
23#define CONFIG_DEFAULT_SECTION "Global"
24
25typedef struct config_t config_t;
26typedef struct config_section_node_t config_section_node_t;
27
28// Creates a new config object with no entries (i.e. not backed by a file).
29// This function returns a config object or NULL on error. Clients must call
30// |config_free| on the returned handle when it is no longer required.
31config_t *config_new_empty(void);
32
33// Loads the specified file and returns a handle to the config file. If there
34// was a problem loading the file or allocating memory, this function returns
35// NULL. Clients must call |config_free| on the returned handle when it is no
36// longer required. |filename| must not be NULL and must point to a readable
37// file on the filesystem.
38config_t *config_new(const char *filename);
39
40// Frees resources associated with the config file. No further operations may
41// be performed on the |config| object after calling this function. |config|
42// may be NULL.
43void config_free(config_t *config);
44
45// Returns true if the config file contains a section named |section|. If
46// the section has no key/value pairs in it, this function will return false.
47// |config| and |section| must not be NULL.
48bool config_has_section(const config_t *config, const char *section);
49
50// Returns true if the config file has a key named |key| under |section|.
51// Returns false otherwise. |config|, |section|, and |key| must not be NULL.
52bool config_has_key(const config_t *config, const char *section, const char *key);
53
54// Returns the integral value for a given |key| in |section|. If |section|
55// or |key| do not exist, or the value cannot be fully converted to an integer,
56// this function returns |def_value|. |config|, |section|, and |key| must not
57// be NULL.
58int config_get_int(const config_t *config, const char *section, const char *key, int def_value);
59
60// Returns the boolean value for a given |key| in |section|. If |section|
61// or |key| do not exist, or the value cannot be converted to a boolean, this
62// function returns |def_value|. |config|, |section|, and |key| must not be NULL.
63bool config_get_bool(const config_t *config, const char *section, const char *key, bool def_value);
64
65// Returns the string value for a given |key| in |section|. If |section| or
66// |key| do not exist, this function returns |def_value|. The returned string
67// is owned by the config module and must not be freed. |config|, |section|,
68// and |key| must not be NULL. |def_value| may be NULL.
69const char *config_get_string(const config_t *config, const char *section, const char *key, const char *def_value);
70
71// Sets an integral value for the |key| in |section|. If |key| or |section| do
72// not already exist, this function creates them. |config|, |section|, and |key|
73// must not be NULL.
74void config_set_int(config_t *config, const char *section, const char *key, int value);
75
76// Sets a boolean value for the |key| in |section|. If |key| or |section| do
77// not already exist, this function creates them. |config|, |section|, and |key|
78// must not be NULL.
79void config_set_bool(config_t *config, const char *section, const char *key, bool value);
80
81// Sets a string value for the |key| in |section|. If |key| or |section| do
82// not already exist, this function creates them. |config|, |section|, |key|, and
83// |value| must not be NULL.
84void config_set_string(config_t *config, const char *section, const char *key, const char *value);
85
86// Removes |section| from the |config| (and, as a result, all keys in the section).
87// Returns true if |section| was found and removed from |config|, false otherwise.
88// Neither |config| nor |section| may be NULL.
89bool config_remove_section(config_t *config, const char *section);
90
91// Removes one specific |key| residing in |section| of the |config|. Returns true
92// if the section and key were found and the key was removed, false otherwise.
93// None of |config|, |section|, or |key| may be NULL.
94bool config_remove_key(config_t *config, const char *section, const char *key);
95
96// Returns an iterator to the first section in the config file. If there are no
97// sections, the iterator will equal the return value of |config_section_end|.
98// The returned pointer must be treated as an opaque handle and must not be freed.
99// The iterator is invalidated on any config mutating operation. |config| may not
100// be NULL.
101const config_section_node_t *config_section_begin(const config_t *config);
102
103// Returns an iterator to one past the last section in the config file. It does not
104// represent a valid section, but can be used to determine if all sections have been
105// iterated over. The returned pointer must be treated as an opaque handle and must
106// not be freed and must not be iterated on (must not call |config_section_next| on
107// it). |config| may not be NULL.
108const config_section_node_t *config_section_end(const config_t *config);
109
110// Moves |iter| to the next section. If there are no more sections, |iter| will
111// equal the value of |config_section_end|. |iter| may not be NULL and must be
112// a pointer returned by either |config_section_begin| or |config_section_next|.
113const config_section_node_t *config_section_next(const config_section_node_t *iter);
114
115// Returns the name of the section referred to by |iter|. The returned pointer is
116// owned by the config module and must not be freed by the caller. The pointer will
117// remain valid until |config_free| is called. |iter| may not be NULL and must not
118// equal the value returned by |config_section_end|.
119const char *config_section_name(const config_section_node_t *iter);
120
121// Saves |config| to a file given by |filename|. Note that this could be a destructive
122// operation: if |filename| already exists, it will be overwritten. The config
123// module does not preserve comments or formatting so if a config file was opened
124// with |config_new| and subsequently overwritten with |config_save|, all comments
125// and special formatting in the original file will be lost. Neither |config| nor
126// |filename| may be NULL.
127bool config_save(const config_t *config, const char *filename);
128