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1 | /* Private implementation details of interface between gdb and its |
2 | extension languages. | |
3 | ||
4 | Copyright (C) 2013 Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #ifndef EXTENSION_PRIV_H | |
22 | #define EXTENSION_PRIV_H | |
23 | ||
24 | #include "extension.h" | |
25 | ||
26 | /* The return code for some API calls. */ | |
27 | ||
28 | enum ext_lang_rc | |
29 | { | |
30 | /* The operation completed successfully. */ | |
31 | EXT_LANG_RC_OK, | |
32 | ||
33 | /* The operation was not performed (e.g., no pretty-printer). */ | |
34 | EXT_LANG_RC_NOP, | |
35 | ||
36 | /* There was an error (e.g., Python error while printing a value). | |
37 | When an error occurs no further extension languages are tried. | |
38 | This is to preserve existing behaviour, and because it's convenient | |
39 | for Python developers. | |
40 | Note: This is different than encountering a memory error trying to read | |
41 | a value for pretty-printing. Here we're referring to, e.g., programming | |
42 | errors that trigger an exception in the extension language. */ | |
43 | EXT_LANG_RC_ERROR | |
44 | }; | |
45 | ||
46 | /* High level description of an extension/scripting language. | |
47 | An entry for each is compiled into GDB regardless of whether the support | |
48 | is present. This is done so that we can issue meaningful errors if the | |
49 | support is not compiled in. */ | |
50 | ||
51 | struct extension_language_defn | |
52 | { | |
53 | /* Enum of the extension language. */ | |
54 | enum extension_language language; | |
55 | ||
56 | /* The name of the extension language, lowercase. E.g., python. */ | |
57 | const char *name; | |
58 | ||
59 | /* The capitalized name of the extension language. | |
60 | For python this is "Python". For gdb this is "GDB". */ | |
61 | const char *capitalized_name; | |
62 | ||
63 | /* The file suffix of this extension language. E.g., ".py". */ | |
64 | const char *suffix; | |
65 | ||
66 | /* The suffix of per-objfile scripts to auto-load. | |
67 | E.g., When the program loads libfoo.so, look for libfoo.so-gdb.py. */ | |
68 | const char *auto_load_suffix; | |
69 | ||
70 | /* We support embedding external extension language code in GDB's own | |
71 | scripting language. We do this by having a special command that begins | |
72 | the extension language snippet, and terminate it with "end". | |
73 | This specifies the control type used to implement this. */ | |
74 | enum command_control_type cli_control_type; | |
75 | ||
76 | /* A pointer to the "methods" to load scripts in this language, | |
77 | or NULL if the support is not compiled into GDB. */ | |
78 | const struct extension_language_script_ops *script_ops; | |
79 | ||
80 | /* Either a pointer to the "methods" of the extension language interface | |
81 | or NULL if the support is not compiled into GDB. | |
82 | This is also NULL for GDB's own scripting language which is relatively | |
83 | primitive, and doesn't provide these features. */ | |
84 | const struct extension_language_ops *ops; | |
85 | }; | |
86 | ||
87 | /* The interface for loading scripts from external extension languages, | |
88 | as well as GDB's own scripting language. | |
89 | All of these methods are required to be implemented. */ | |
90 | ||
91 | struct extension_language_script_ops | |
92 | { | |
93 | /* Load a script. This is called, e.g., via the "source" command. | |
94 | If there's an error while processing the script this function may, | |
95 | but is not required to, throw an error. */ | |
96 | script_sourcer_func *script_sourcer; | |
97 | ||
98 | /* Load a script attached to an objfile. | |
99 | If there's an error while processing the script this function may, | |
100 | but is not required to, throw an error. */ | |
101 | objfile_script_sourcer_func *objfile_script_sourcer; | |
102 | ||
103 | /* Return non-zero if auto-loading scripts in this extension language | |
104 | is enabled. */ | |
105 | int (*auto_load_enabled) (const struct extension_language_defn *); | |
106 | }; | |
107 | ||
108 | /* The interface for making calls from GDB to an external extension | |
109 | language. This is for non-script-loading related functionality, like | |
110 | pretty-printing, etc. The reason these are separated out is GDB's own | |
111 | scripting language makes use of extension_language_script_opts, but it | |
112 | makes no use of these. There is no (current) intention to split | |
113 | extension_language_ops up any further. | |
114 | All of these methods are optional and may be NULL, except where | |
115 | otherwise indicated. */ | |
116 | ||
117 | struct extension_language_ops | |
118 | { | |
119 | /* Called at the end of gdb initialization to give the extension language | |
120 | an opportunity to finish up. This is useful for things like adding | |
121 | new commands where one has to wait until gdb itself is initialized. */ | |
122 | void (*finish_initialization) (const struct extension_language_defn *); | |
123 | ||
124 | /* Return non-zero if the extension language successfully initialized. | |
125 | This method is required. */ | |
126 | int (*initialized) (const struct extension_language_defn *); | |
127 | ||
128 | /* Process a sequence of commands embedded in GDB's own scripting language. | |
129 | E.g., | |
130 | python | |
131 | print 42 | |
132 | end */ | |
133 | void (*eval_from_control_command) (const struct extension_language_defn *, | |
134 | struct command_line *); | |
135 | ||
136 | /* Type-printing support: | |
137 | start_type_printers, apply_type_printers, free_type_printers. | |
138 | These methods are optional and may be NULL, but if one of them is | |
139 | implemented then they all must be. */ | |
140 | ||
141 | /* Called before printing a type. */ | |
142 | void (*start_type_printers) (const struct extension_language_defn *, | |
143 | struct ext_lang_type_printers *); | |
144 | ||
145 | /* Try to pretty-print TYPE. If successful the pretty-printed type is | |
146 | stored in *PRETTIED_TYPE, and the caller must free it. | |
147 | Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the type | |
148 | is not recognized, and EXT_LANG_RC_ERROR if an error was encountered. | |
149 | This function has a bit of a funny name, since it actually applies | |
150 | recognizers, but this seemed clearer given the start_type_printers | |
151 | and free_type_printers functions. */ | |
152 | enum ext_lang_rc (*apply_type_printers) | |
153 | (const struct extension_language_defn *, | |
154 | const struct ext_lang_type_printers *, | |
155 | struct type *, char **prettied_type); | |
156 | ||
157 | /* Called after a type has been printed to give the type pretty-printer | |
158 | mechanism an opportunity to clean up. */ | |
159 | void (*free_type_printers) (const struct extension_language_defn *, | |
160 | struct ext_lang_type_printers *); | |
161 | ||
162 | /* Try to pretty-print a value of type TYPE located at VALADDR | |
163 | + EMBEDDED_OFFSET, which came from the inferior at address ADDRESS | |
164 | + EMBEDDED_OFFSET, onto stdio stream STREAM according to OPTIONS. | |
165 | VAL is the whole object that came from ADDRESS. VALADDR must point to | |
166 | the head of VAL's contents buffer. | |
167 | Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the value | |
168 | is not recognized, and EXT_LANG_RC_ERROR if an error was encountered. */ | |
169 | enum ext_lang_rc (*apply_val_pretty_printer) | |
170 | (const struct extension_language_defn *, | |
171 | struct type *type, const gdb_byte *valaddr, | |
172 | int embedded_offset, CORE_ADDR address, | |
173 | struct ui_file *stream, int recurse, | |
174 | const struct value *val, const struct value_print_options *options, | |
175 | const struct language_defn *language); | |
176 | ||
177 | /* GDB access to the "frame filter" feature. | |
178 | FRAME is the source frame to start frame-filter invocation. FLAGS is an | |
179 | integer holding the flags for printing. The following elements of | |
180 | the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS: | |
181 | PRINT_LEVEL is a flag indicating whether to print the frame's | |
182 | relative level in the output. PRINT_FRAME_INFO is a flag that | |
183 | indicates whether this function should print the frame | |
184 | information, PRINT_ARGS is a flag that indicates whether to print | |
185 | frame arguments, and PRINT_LOCALS, likewise, with frame local | |
186 | variables. ARGS_TYPE is an enumerator describing the argument | |
187 | format, OUT is the output stream to print. FRAME_LOW is the | |
188 | beginning of the slice of frames to print, and FRAME_HIGH is the | |
189 | upper limit of the frames to count. Returns SCR_BT_ERROR on error, | |
190 | or SCR_BT_COMPLETED on success. */ | |
191 | enum ext_lang_bt_status (*apply_frame_filter) | |
192 | (const struct extension_language_defn *, | |
193 | struct frame_info *frame, int flags, enum ext_lang_frame_args args_type, | |
194 | struct ui_out *out, int frame_low, int frame_high); | |
195 | ||
196 | /* Update values held by the extension language when OBJFILE is discarded. | |
197 | New global types must be created for every such value, which must then be | |
198 | updated to use the new types. | |
199 | This function typically just iterates over all appropriate values and | |
200 | calls preserve_one_value for each one. | |
201 | COPIED_TYPES is used to prevent cycles / duplicates and is passed to | |
202 | preserve_one_value. */ | |
203 | void (*preserve_values) (const struct extension_language_defn *, | |
204 | struct objfile *objfile, htab_t copied_types); | |
205 | ||
206 | /* Return non-zero if there is a stop condition for the breakpoint. | |
207 | This is used to implement the restriction that a breakpoint may have | |
208 | at most one condition. */ | |
209 | int (*breakpoint_has_cond) (const struct extension_language_defn *, | |
210 | struct breakpoint *); | |
211 | ||
212 | /* Return a value of enum ext_lang_bp_stop indicating if there is a stop | |
213 | condition for the breakpoint, and if so whether the program should | |
214 | stop. This is called when the program has stopped at the specified | |
215 | breakpoint. | |
216 | While breakpoints can have at most one condition, this is called for | |
217 | every extension language, even if another extension language has a | |
218 | "stop" method: other kinds of breakpoints may be implemented using | |
219 | this method, e.g., "finish breakpoints" in Python. */ | |
220 | enum ext_lang_bp_stop (*breakpoint_cond_says_stop) | |
221 | (const struct extension_language_defn *, struct breakpoint *); | |
222 | ||
223 | /* The next three are used to connect GDB's SIGINT handling with the | |
224 | extension language's. | |
225 | ||
226 | Terminology: If an extension language can use GDB's SIGINT handling then | |
227 | we say the extension language has "cooperative SIGINT handling". | |
228 | Python is an example of this. | |
229 | ||
230 | These need not be implemented, but if one of them is implemented | |
231 | then they all must be. */ | |
232 | ||
233 | /* Clear the SIGINT indicator. */ | |
234 | void (*clear_quit_flag) (const struct extension_language_defn *); | |
235 | ||
236 | /* Set the SIGINT indicator. | |
237 | This is called by GDB's SIGINT handler and must be async-safe. */ | |
238 | void (*set_quit_flag) (const struct extension_language_defn *); | |
239 | ||
240 | /* Return non-zero if a SIGINT has occurred. | |
241 | This is expected to also clear the indicator. */ | |
242 | int (*check_quit_flag) (const struct extension_language_defn *); | |
243 | ||
244 | /* Called before gdb prints its prompt, giving extension languages an | |
245 | opportunity to change it with set_prompt. | |
246 | Returns EXT_LANG_RC_OK if the prompt was changed, EXT_LANG_RC_NOP if | |
247 | the prompt was not changed, and EXT_LANG_RC_ERROR if an error was | |
248 | encountered. | |
249 | Extension languages are called in order, and once the prompt is | |
250 | changed or an error occurs no further languages are called. */ | |
251 | enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *, | |
252 | const char *current_gdb_prompt); | |
253 | }; | |
254 | ||
255 | /* State necessary to restore a signal handler to its previous value. */ | |
256 | ||
257 | struct signal_handler | |
258 | { | |
259 | /* Non-zero if "handler" has been set. */ | |
260 | int handler_saved; | |
261 | ||
262 | /* The signal handler. */ | |
263 | RETSIGTYPE (*handler) (); | |
264 | }; | |
265 | ||
266 | /* State necessary to restore the currently active extension language | |
267 | to is previous value. */ | |
268 | ||
269 | struct active_ext_lang_state | |
270 | { | |
271 | /* The previously active extension language. */ | |
272 | const struct extension_language_defn *ext_lang; | |
273 | ||
274 | /* Its SIGINT handler. */ | |
275 | struct signal_handler sigint_handler; | |
276 | }; | |
277 | ||
278 | extern const struct extension_language_defn *get_active_ext_lang (void); | |
279 | ||
280 | extern struct active_ext_lang_state *set_active_ext_lang | |
281 | (const struct extension_language_defn *); | |
282 | ||
283 | extern void restore_active_ext_lang (struct active_ext_lang_state *previous); | |
284 | ||
285 | #endif /* EXTENSION_PRIV_H */ |