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Commit | Line | Data |
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1 | ------------------------------------------------------------------------------- | |
2 | HACKING | |
3 | ------------------------------------------------------------------------------- | |
4 | ||
5 | Coding style | |
6 | ------------ | |
7 | ||
8 | This project is programmed using the Linux kernel coding style, see | |
9 | http://lxr.linux.no/linux/Documentation/CodingStyle for details. | |
10 | ||
11 | Please use the same style for any code contributions, thanks! | |
12 | ||
13 | ||
14 | Contributions | |
15 | ------------- | |
16 | ||
17 | - Patches should be sent to the development mailinglist at | |
18 | sigrok-devel@lists.sourceforge.net (please subscribe to the list first). | |
19 | ||
20 | https://lists.sourceforge.net/lists/listinfo/sigrok-devel | |
21 | ||
22 | - Alternatively, you can also clone the git repository and let us know | |
23 | from where to pull/review your changes. You can use gitorious.org, | |
24 | github.com, or any other public git hosting site. | |
25 | ||
26 | ||
27 | Adding a new hardware driver | |
28 | ---------------------------- | |
29 | ||
30 | The simple, scripted way (recommended): | |
31 | --------------------------------------- | |
32 | ||
33 | Use the 'new-driver' script from the sigrok-util repo: | |
34 | ||
35 | $ git clone git://sigrok.org/sigrok-util | |
36 | $ cd sigrok-util/source | |
37 | $ ./new-driver "Tondaj SL-814" | |
38 | ||
39 | The example above generates a patch file against the current libsigrok | |
40 | development git tree which adds a simple "stub" driver for your device | |
41 | (the Tondaj SL-814 sound level meter in this case). | |
42 | ||
43 | You can apply it like this: | |
44 | ||
45 | $ cd libsigrok | |
46 | $ git am 0001-tondaj-sl-814-Initial-driver-skeleton.patch | |
47 | ||
48 | You can now edit the files in the hardware/tondaj-sl-814 directory as needed | |
49 | and implement your driver based on the skeleton files there. That means your | |
50 | patch submission later will consist of at least two patches: the initial one | |
51 | adding the skeleton driver, and one or more additional patches that actually | |
52 | implement the respective driver code. | |
53 | ||
54 | ||
55 | The manual way: | |
56 | --------------- | |
57 | ||
58 | This is a rough overview of what you need to do in order to add a new driver | |
59 | (using the Tondaj SL-814 device as example). It's basically what the | |
60 | 'new-driver' script (see above) does for you: | |
61 | ||
62 | - configure.ac: | |
63 | - Add an --enable-tondaj-sl-814 option. | |
64 | - Add "hardware/tondaj-sl-814/Makefile" to the AC_CONFIG_FILES list. | |
65 | - Add and entry for the device in the "Enabled hardware drivers" list | |
66 | at the bottom of the file. | |
67 | - hardware/Makefile.am: Add "tondaj-sl-814" to the SUBDIRS variable. | |
68 | - hwdriver.c: Add a tondaj_sl_814_driver_info entry in two places. | |
69 | - hardware/tondaj-sl-814/ directory: Add the following files: | |
70 | Makefile.am, api.c, protocol.c, protocol.h | |
71 | ||
72 | See existing drivers or the 'new-driver' output for the details. | |
73 | ||
74 | ||
75 | Random notes | |
76 | ------------ | |
77 | ||
78 | - Don't do variable declarations in compound statements, only at the | |
79 | beginning of a function. | |
80 | ||
81 | - Generally avoid assigning values to variables at declaration time, | |
82 | especially so for complex and/or run-time dependent values. | |
83 | ||
84 | - Consistently use g_try_malloc() / g_try_malloc0(). Do not use standard | |
85 | malloc()/calloc() if it can be avoided (sometimes other libs such | |
86 | as libftdi can return malloc()'d memory, for example). | |
87 | ||
88 | - Always properly match allocations with the proper *free() functions. If | |
89 | glib's g_try_malloc()/g_try_malloc0() was used, use g_free() to free the | |
90 | memory. Otherwise use standard free(). Never use the wrong function! | |
91 | ||
92 | - Never use g_malloc() or g_malloc0(). These functions do not return NULL | |
93 | if not enough memory is available but rather lead to an exit() or segfault | |
94 | instead. This behaviour is not acceptable for libraries. | |
95 | Use g_try_malloc()/g_try_malloc0() instead and check the return value. | |
96 | ||
97 | - You should never print any messages (neither to stdout nor stderr nor | |
98 | elsewhere) "manually" via e.g. printf() or g_log() or similar functions. | |
99 | Only sr_err()/sr_warn()/sr_info()/sr_dbg()/sr_spew() should be used. | |
100 | ||
101 | - Use glib's gboolean / TRUE / FALSE for boolean types consistently. | |
102 | Do not use <stdbool.h> and its true / false, and do not invent private | |
103 | definitions for this either. | |
104 | ||
105 | - Consistently use the same naming convention for #include guards in headers: | |
106 | <PROJECTNAME>_<PATH_TO_FILE>_<FILE> | |
107 | This ensures that all #include guards are always unique and consistent. | |
108 | Examples: LIBSIGROK_LIBSIGROK_H, LIBSIGROK_HARDWARE_MIC_985XX_PROTOCOL_H | |
109 | ||
110 | - Consistently use the same naming convention for API functions: | |
111 | <libprefix>_<groupname>_<action>(). | |
112 | ||
113 | Examples: | |
114 | sr_log_loglevel_set(), sr_log_loglevel_get(), sr_log_handler_set(), | |
115 | sr_log_handler_set_default(), and so on. | |
116 | Or: | |
117 | sr_session_new(), sr_session_destroy(), sr_session_load(), and so on. | |
118 | ||
119 | Getter/setter function names should usually end with "_get" or "_set". | |
120 | Functions creating new "objects" should end with "_new". | |
121 | Functions destroying "objects" should end with "_destroy". | |
122 | Functions adding or removing items (e.g. from lists) should end with | |
123 | either "_add" or "_remove". | |
124 | Functions operating on all items from a list (not on only one of them), | |
125 | should end with "_all", e.g. "_remove_all", "_get_all", and so on. | |
126 | Use "_remove_all" in favor of "_clear" for consistency. | |
127 | ||
128 | - All enums should generally use an explicit start number of 10000. | |
129 | If there are multiple "categories" in the enum entries, each category | |
130 | should be 10000 entries apart from the next one. The start of categories | |
131 | are thus 10000, 20000, 30000, and so on. | |
132 | ||
133 | Adding items to an enum MUST always append to a "category", never add | |
134 | items in the middle of a category. The order of items MUST NOT be changed. | |
135 | Any of the above would break the ABI. | |
136 | ||
137 | The enum item 0 is special and is used as terminator in some lists, thus | |
138 | enums should not use this for "valid" entries (and start at 10000 instead). | |
139 | ||
140 | ||
141 | Doxygen | |
142 | ------- | |
143 | ||
144 | - In Doxygen comments, put an empty line between the block of @param lines | |
145 | and the final @return line. The @param lines themselves (if there is more | |
146 | than one) are not separated by empty lines. | |
147 | ||
148 | - Mark private functions (SR_PRIV) with /** @private */, so that Doxygen | |
149 | doesn't include them in the output. Functions that are "static" anyway | |
150 | don't need to be marked like this. | |
151 | ||
152 | - Mark private variables/#defines with /** @cond PRIVATE */ and | |
153 | /** @endcond */, so that Doxygen doesn't include them in the output. | |
154 | Variables that are "static" don't need to be marked like this. | |
155 | ||
156 | - Mark all public API functions (SR_API) with a @since tag which indicates | |
157 | in which release the respective function was added (e.g. "@since 0.1.0"). | |
158 | ||
159 | If the function has existed before, but its API changed later, the @since | |
160 | tag should mention only the release when the API last changed. | |
161 | ||
162 | Example: The sr_foo() call was added in 0.1.0, but the API changed in | |
163 | the later 0.2.0 release. The docs should read "@since 0.2.0" in that case. | |
164 | ||
165 | Non-public functions (static ones, and those marked SR_PRIV) don't need | |
166 | to have @since markers. | |
167 | ||
168 | The @since tag should be the last one, i.e. it should come after @param, | |
169 | @return, @see, and so on. | |
170 | ||
171 | ||
172 | Testsuite | |
173 | --------- | |
174 | ||
175 | You can run the libsigrok testsuite using: | |
176 | ||
177 | $ make check | |
178 | ||
179 | ||
180 | Release engineering | |
181 | ------------------- | |
182 | ||
183 | See | |
184 | ||
185 | http://sigrok.org/wiki/Developers/Release_process | |
186 | ||
187 | for a list of items that need to be done when releasing a new tarball. | |
188 |