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Add optional bidirectional interface to i3bar. (ver.2)

Patch status: superseded

Patch by enkore

Long description:

If the child specifies bidirectional:1 in the protocl header,
a JSON array will be streamed to it's stdin.
It consists of maps with at least one key (command).

Such a map is emitted if the user clicks on a status block. i.e.
{"command":"block_clicked","name":"some_block_name","instance":"optional_instance"}

The basic output format is like the rest of the i3bar protocol (i.e.
a new line after each element (map in this case))

The second version of this patch mainly introduced a better API for sending
commands.

To apply this patch, use:
curl http://cr.i3wm.org/patch/71/raw.patch | git am

b/docs/i3bar-protocol

@@ -51,7 +51,7 @@ consists of a single JSON hash:
 
 *All features example*:
 ------------------------------
-{ "version": 1, "stop_signal": 10, "cont_signal": 12 }
+{ "version": 1, "stop_signal": 10, "cont_signal": 12, "bidirectional": 1 }
 ------------------------------
 
 (Note that before i3 v4.3 the precise format had to be +{"version":1}+,
@@ -110,6 +110,9 @@ cont_signal::
 	Specify to i3bar the signal (as an integer)to send to continue your
 	processing.
 	The default value (if none is specified) is SIGCONT.
+bidirectional::
+	If specified and 1 i3bar will write a infinite array (same as above)
+	to your stdin.
 
 === Blocks in detail
 
@@ -183,3 +186,20 @@ An example of a block which uses all possible entries follows:
  "instance": "eth0"
 }
 ------------------------------------------
+
+=== Bidirectional communication
+
+If enabled i3bar will send you notifications about certain events, currently
+only one such notification is implmented: block_clicked.
+It is send if the user clicks on a block and looks like this:
+
+*Example*:
+------------------------------------------
+{
+ "command": "block_clicked",
+ "name": "ethernet",
+ "instance": "eth0",
+ "x": 1320,
+ "y": 1400
+}
+------------------------------------------

b/i3bar/include/child.h

@@ -33,6 +33,12 @@ typedef struct {
      * The signal requested by the client to inform it of theun hidden state of i3bar
      */
     int cont_signal;
+
+    /**
+     * Enable bi-directional communication, i.e. on-click events
+     */
+    bool bidirectional;
+    int bidirectional_init;
 } i3bar_child;
 
 /*
@@ -68,4 +74,10 @@ void stop_child(void);
  */
 void cont_child(void);
 
+/*
+ * ends the block_clicked command to the child
+ *
+ */
+void send_block_clicked(const char *name, const char *instance, int x, int y);
+
 #endif

b/i3bar/include/common.h

@@ -50,6 +50,10 @@ struct status_block {
     uint32_t x_offset;
     uint32_t x_append;
 
+    /* Optional */
+    char *name;
+    char *instance;
+
     TAILQ_ENTRY(status_block) blocks;
 };
 

b/i3bar/src/child.c

@@ -21,6 +21,7 @@
 #include <yajl/yajl_common.h>
 #include <yajl/yajl_parse.h>
 #include <yajl/yajl_version.h>
+#include <yajl/yajl_gen.h>
 
 #include "common.h"
 
@@ -35,6 +36,9 @@ ev_child *child_sig;
 yajl_callbacks callbacks;
 yajl_handle parser;
 
+/* JSON generator for stdout */
+yajl_gen gen;
+
 typedef struct parser_ctx {
     /* True if one of the parsed blocks was urgent */
     bool has_urgent;
@@ -141,6 +145,18 @@ static int stdin_string(void *context, const unsigned char *val, unsigned int le
             ctx->block.align = ALIGN_CENTER;
         }
     }
+    if (strcasecmp(ctx->last_map_key, "name") == 0) {
+        char *copy = (char*)malloc(len+1);
+        strncpy(copy, (const char *)val, len);
+        copy[len] = 0;
+        ctx->block.name = copy;
+    }
+    if (strcasecmp(ctx->last_map_key, "instance") == 0) {
+        char *copy = (char*)malloc(len+1);
+        strncpy(copy, (const char *)val, len);
+        copy[len] = 0;
+        ctx->block.instance = copy;
+    }
     return 1;
 }
 
@@ -322,6 +338,18 @@ void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
     cleanup();
 }
 
+void child_write_output(void) {
+    if(child.bidirectional) {
+        const unsigned char *output;
+        size_t size;
+        yajl_gen_get_buf(gen, &output, &size);
+        fwrite(output, 1, size, stdout);
+        fwrite("\n", 1, 1, stdout);
+        fflush(stdout);
+        yajl_gen_clear(gen);    
+    }
+}
+
 /*
  * Start a child-process with the specified command and reroute stdin.
  * We actually start a $SHELL to execute the command so we don't have to care
@@ -347,10 +375,14 @@ void start_child(char *command) {
     parser = yajl_alloc(&callbacks, NULL, &parser_context);
 #endif
 
+    gen = yajl_gen_alloc(NULL);
+
     if (command != NULL) {
-        int fd[2];
+        int fd[4];
         if (pipe(fd) == -1)
             err(EXIT_FAILURE, "pipe(fd)");
+        if (pipe(&fd[2]) == -1)
+            err(EXIT_FAILURE, "pipe(fd)");
 
         child.pid = fork();
         switch (child.pid) {
@@ -358,10 +390,10 @@ void start_child(char *command) {
                 ELOG("Couldn't fork(): %s\n", strerror(errno));
                 exit(EXIT_FAILURE);
             case 0:
-                /* Child-process. Reroute stdout and start shell */
-                close(fd[0]);
+                /* Child-process. Reroute streams and start shell */
 
                 dup2(fd[1], STDOUT_FILENO);
+                dup2(fd[2], STDIN_FILENO);
 
                 static const char *shell = NULL;
 
@@ -371,9 +403,9 @@ void start_child(char *command) {
                 execl(shell, shell, "-c", command, (char*) NULL);
                 return;
             default:
-                /* Parent-process. Rerout stdin */
-                close(fd[1]);
+                /* Parent-process. Reroute streams */
 
+                dup2(fd[3], STDOUT_FILENO);
                 dup2(fd[0], STDIN_FILENO);
 
                 break;
@@ -396,6 +428,66 @@ void start_child(char *command) {
 }
 
 /*
+ * Internal helper functions for bidirectional comms
+ *
+ */
+void child_bidi_initialize(void) {
+    if(!child.bidirectional_init) {
+        yajl_gen_array_open(gen);
+        child_write_output();
+        child.bidirectional_init = 1;
+    }    
+}
+
+void child_bidi_key(const char *key) {
+    yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
+}
+
+void child_bidi_open(const char *command) {
+    child_bidi_initialize();
+
+    yajl_gen_map_open(gen);
+
+    child_bidi_key("command");
+    yajl_gen_string(gen, (const unsigned char *)command, strlen(command));
+}
+
+void child_bidi_close(void) {
+    yajl_gen_map_close(gen);
+    child_write_output();
+}
+
+/*
+ * sends the block_clicked command to the child
+ *
+ */
+void send_block_clicked(const char *name, const char *instance, int x, int y) {
+    if(child.bidirectional) {
+        child_bidi_open("block_clicked");
+
+        if(name) {
+            child_bidi_key("name");
+            yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
+        }
+
+        if(instance) {
+            child_bidi_key("instance");
+            yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
+        }
+
+        child_bidi_key("x");
+        yajl_gen_integer(gen, x);
+
+        child_bidi_key("y");
+        yajl_gen_integer(gen, y);
+
+        yajl_gen_map_close(gen);
+
+        child_write_output();
+    }
+}
+
+/*
  * kill()s the child-process (if any). Called when exit()ing.
  *
  */

b/i3bar/src/parse_json_header.c

@@ -31,6 +31,7 @@ static enum {
     KEY_VERSION,
     KEY_STOP_SIGNAL,
     KEY_CONT_SIGNAL,
+    KEY_BIDIRECTIONAL,
     NO_KEY
 } current_key;
 
@@ -51,6 +52,8 @@ static int header_integer(void *ctx, long val) {
         case KEY_CONT_SIGNAL:
             child->cont_signal = val;
             break;
+        case KEY_BIDIRECTIONAL:
+            child->bidirectional = val;
         default:
             break;
     }
@@ -71,6 +74,8 @@ static int header_map_key(void *ctx, const unsigned char *stringval, unsigned in
         current_key = KEY_STOP_SIGNAL;
     } else if (CHECK_KEY("cont_signal")) {
         current_key = KEY_CONT_SIGNAL;
+    } else if (CHECK_KEY("bidirectional")) {
+        current_key = KEY_BIDIRECTIONAL;
     }
     return 1;
 }

b/i3bar/src/xcb.c

@@ -160,7 +160,7 @@ void refresh_statusline(void) {
     xcb_poly_fill_rectangle(xcb_connection, statusline_pm, statusline_clear, 1, &rect);
 
     /* Draw the text of each block. */
-    uint32_t x = 0;
+    uint32_t x = 0; 
     TAILQ_FOREACH(block, &statusline_head, blocks) {
         if (i3string_get_num_bytes(block->full_text) == 0)
             continue;
@@ -306,6 +306,7 @@ void handle_button(xcb_button_press_event_t *event) {
     }
 
     int32_t x = event->event_x >= 0 ? event->event_x : 0;
+    int32_t original_x = x;
 
     DLOG("Got Button %d\n", event->detail);
 
@@ -321,6 +322,36 @@ void handle_button(xcb_button_press_event_t *event) {
                 x -= cur_ws->name_width + 11;
             }
             if (cur_ws == NULL) {
+                /* No workspace button was pressed.
+                 * Check if a status block has been clicked.
+                 * This of course only has an effect,
+                 * if the child reported bidirectional protocol usage. */
+
+                /* First calculate width of tray area */
+                trayclient *trayclient;
+                int tray_width = 0;
+                TAILQ_FOREACH_REVERSE(trayclient, walk->trayclients, tc_head, tailq) {
+                    if (!trayclient->mapped)
+                        continue;
+                    tray_width += (font.height + 2);
+                }
+
+                int block_x = 0, last_block_x;
+                int offset = (walk->rect.w - (statusline_width + tray_width)) - 10;
+                
+                x = original_x - offset > 0 ? original_x - offset : 0;
+
+                struct status_block *block;
+
+                TAILQ_FOREACH(block, &statusline_head, blocks) {
+                    last_block_x = block_x;
+                    block_x += block->width + block->x_offset + block->x_append;
+
+                    if(x <= block_x && x >= last_block_x) {
+                        send_block_clicked(block->name, block->instance, event->event_x, event->event_y);
+                        return;
+                    }
+                }
                 return;
             }
             break;

102	@@ -50,6 +50,10 @@ struct status_block {
103	uint32_t x_offset;
104	uint32_t x_append;
105
106	+ /* Optional */
107	+ char *name;
108	+ char *instance;
109	+
110	TAILQ_ENTRY(status_block) blocks;
111	};
112

117	@@ -21,6 +21,7 @@
118	#include <yajl/yajl_common.h>
119	#include <yajl/yajl_parse.h>
120	#include <yajl/yajl_version.h>
121	+#include <yajl/yajl_gen.h>
122
123	#include "common.h"
124
125	@@ -35,6 +36,9 @@ ev_child *child_sig;
126	yajl_callbacks callbacks;
127	yajl_handle parser;
128
129	+/* JSON generator for stdout */
130	+yajl_gen gen;
131	+
132	typedef struct parser_ctx {
133	/* True if one of the parsed blocks was urgent */
134	bool has_urgent;
135	@@ -141,6 +145,18 @@ static int stdin_string(void context, const unsigned char val, unsigned int le
136	ctx->block.align = ALIGN_CENTER;
137	}
138	}
139	+ if (strcasecmp(ctx->last_map_key, "name") == 0) {
140	+ char copy = (char)malloc(len+1);
141	+ strncpy(copy, (const char *)val, len);
142	+ copy[len] = 0;
143	+ ctx->block.name = copy;
144	+ }
145	+ if (strcasecmp(ctx->last_map_key, "instance") == 0) {
146	+ char copy = (char)malloc(len+1);
147	+ strncpy(copy, (const char *)val, len);
148	+ copy[len] = 0;
149	+ ctx->block.instance = copy;
150	+ }
151	return 1;
152	}
153
154	@@ -322,6 +338,18 @@ void child_sig_cb(struct ev_loop loop, ev_child watcher, int revents) {
155	cleanup();
156	}
157
158	+void child_write_output(void) {
159	+ if(child.bidirectional) {
160	+ const unsigned char *output;
161	+ size_t size;
162	+ yajl_gen_get_buf(gen, &output, &size);
163	+ fwrite(output, 1, size, stdout);
164	+ fwrite("\n", 1, 1, stdout);
165	+ fflush(stdout);
166	+ yajl_gen_clear(gen);
167	+ }
168	+}
169	+
170	/*
171	* Start a child-process with the specified command and reroute stdin.
172	* We actually start a $SHELL to execute the command so we don't have to care
173	@@ -347,10 +375,14 @@ void start_child(char *command) {
174	parser = yajl_alloc(&callbacks, NULL, &parser_context);
175	#endif
176
177	+ gen = yajl_gen_alloc(NULL);
178	+
179	if (command != NULL) {
180	- int fd[2];
181	+ int fd[4];
182	if (pipe(fd) == -1)
183	err(EXIT_FAILURE, "pipe(fd)");
184	+ if (pipe(&fd[2]) == -1)
185	+ err(EXIT_FAILURE, "pipe(fd)");
186
187	child.pid = fork();
188	switch (child.pid) {
189	@@ -358,10 +390,10 @@ void start_child(char *command) {
190	ELOG("Couldn't fork(): %s\n", strerror(errno));
191	exit(EXIT_FAILURE);
192	case 0:
193	- /* Child-process. Reroute stdout and start shell */
194	- close(fd[0]);
195	+ /* Child-process. Reroute streams and start shell */
196
197	dup2(fd[1], STDOUT_FILENO);
198	+ dup2(fd[2], STDIN_FILENO);
199
200	static const char *shell = NULL;
201
202	@@ -371,9 +403,9 @@ void start_child(char *command) {
203	execl(shell, shell, "-c", command, (char*) NULL);
204	return;
205	default:
206	- /* Parent-process. Rerout stdin */
207	- close(fd[1]);
208	+ /* Parent-process. Reroute streams */
209
210	+ dup2(fd[3], STDOUT_FILENO);
211	dup2(fd[0], STDIN_FILENO);
212
213	break;
214	@@ -396,6 +428,66 @@ void start_child(char *command) {
215	}
216
217	/*
218	+ * Internal helper functions for bidirectional comms
219	+ *
220	+ */
221	+void child_bidi_initialize(void) {
222	+ if(!child.bidirectional_init) {
223	+ yajl_gen_array_open(gen);
224	+ child_write_output();
225	+ child.bidirectional_init = 1;
226	+ }
227	+}
228	+
229	+void child_bidi_key(const char *key) {
230	+ yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
231	+}
232	+
233	+void child_bidi_open(const char *command) {
234	+ child_bidi_initialize();
235	+
236	+ yajl_gen_map_open(gen);
237	+
238	+ child_bidi_key("command");
239	+ yajl_gen_string(gen, (const unsigned char *)command, strlen(command));
240	+}
241	+
242	+void child_bidi_close(void) {
243	+ yajl_gen_map_close(gen);
244	+ child_write_output();
245	+}
246	+
247	+/*
248	+ * sends the block_clicked command to the child
249	+ *
250	+ */
251	+void send_block_clicked(const char name, const char instance, int x, int y) {
252	+ if(child.bidirectional) {
253	+ child_bidi_open("block_clicked");
254	+
255	+ if(name) {
256	+ child_bidi_key("name");
257	+ yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
258	+ }
259	+
260	+ if(instance) {
261	+ child_bidi_key("instance");
262	+ yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
263	+ }
264	+
265	+ child_bidi_key("x");
266	+ yajl_gen_integer(gen, x);
267	+
268	+ child_bidi_key("y");
269	+ yajl_gen_integer(gen, y);
270	+
271	+ yajl_gen_map_close(gen);
272	+
273	+ child_write_output();
274	+ }
275	+}
276	+
277	+/*
278	* kill()s the child-process (if any). Called when exit()ing.
279	*
280	*/

285	@@ -31,6 +31,7 @@ static enum {
286	KEY_VERSION,
287	KEY_STOP_SIGNAL,
288	KEY_CONT_SIGNAL,
289	+ KEY_BIDIRECTIONAL,
290	NO_KEY
291	} current_key;
292
293	@@ -51,6 +52,8 @@ static int header_integer(void *ctx, long val) {
294	case KEY_CONT_SIGNAL:
295	child->cont_signal = val;
296	break;
297	+ case KEY_BIDIRECTIONAL:
298	+ child->bidirectional = val;
299	default:
300	break;
301	}
302	@@ -71,6 +74,8 @@ static int header_map_key(void ctx, const unsigned char stringval, unsigned in
303	current_key = KEY_STOP_SIGNAL;
304	} else if (CHECK_KEY("cont_signal")) {
305	current_key = KEY_CONT_SIGNAL;
306	+ } else if (CHECK_KEY("bidirectional")) {
307	+ current_key = KEY_BIDIRECTIONAL;
308	}
309	return 1;
310	}

315	@@ -160,7 +160,7 @@ void refresh_statusline(void) {
316	xcb_poly_fill_rectangle(xcb_connection, statusline_pm, statusline_clear, 1, &rect);
317
318	/* Draw the text of each block. */
319	- uint32_t x = 0;
320	+ uint32_t x = 0;
321	TAILQ_FOREACH(block, &statusline_head, blocks) {
322	if (i3string_get_num_bytes(block->full_text) == 0)
323	continue;
324	@@ -306,6 +306,7 @@ void handle_button(xcb_button_press_event_t *event) {
325	}
326
327	int32_t x = event->event_x >= 0 ? event->event_x : 0;
328	+ int32_t original_x = x;
329
330	DLOG("Got Button %d\n", event->detail);
331
332	@@ -321,6 +322,36 @@ void handle_button(xcb_button_press_event_t *event) {
333	x -= cur_ws->name_width + 11;
334	}
335	if (cur_ws == NULL) {
336	+ /* No workspace button was pressed.
337	+ * Check if a status block has been clicked.
338	+ * This of course only has an effect,
339	+ * if the child reported bidirectional protocol usage. */
340	+
341	+ /* First calculate width of tray area */
342	+ trayclient *trayclient;
343	+ int tray_width = 0;
344	+ TAILQ_FOREACH_REVERSE(trayclient, walk->trayclients, tc_head, tailq) {
345	+ if (!trayclient->mapped)
346	+ continue;
347	+ tray_width += (font.height + 2);
348	+ }
349	+
350	+ int block_x = 0, last_block_x;
351	+ int offset = (walk->rect.w - (statusline_width + tray_width)) - 10;
352	+
353	+ x = original_x - offset > 0 ? original_x - offset : 0;
354	+
355	+ struct status_block *block;
356	+
357	+ TAILQ_FOREACH(block, &statusline_head, blocks) {
358	+ last_block_x = block_x;
359	+ block_x += block->width + block->x_offset + block->x_append;
360	+
361	+ if(x <= block_x && x >= last_block_x) {
362	+ send_block_clicked(block->name, block->instance, event->event_x, event->event_y);
363	+ return;
364	+ }
365	+ }
366	return;
367	}
368	break;

30	@@ -51,7 +51,7 @@ consists of a single JSON hash:
31
32	All features example:
33	------------------------------
34	-{ "version": 1, "stop_signal": 10, "cont_signal": 12 }
35	+{ "version": 1, "stop_signal": 10, "cont_signal": 12, "bidirectional": 1 }
36	------------------------------
37
38	(Note that before i3 v4.3 the precise format had to be +{"version":1}+,
39	@@ -110,6 +110,9 @@ cont_signal::
40	Specify to i3bar the signal (as an integer)to send to continue your
41	processing.
42	The default value (if none is specified) is SIGCONT.
43	+bidirectional::
44	+ If specified and 1 i3bar will write a infinite array (same as above)
45	+ to your stdin.
46
47	=== Blocks in detail
48
49	@@ -183,3 +186,20 @@ An example of a block which uses all possible entries follows:
50	"instance": "eth0"
51	}
52	------------------------------------------
53	+
54	+=== Bidirectional communication
55	+
56	+If enabled i3bar will send you notifications about certain events, currently
57	+only one such notification is implmented: block_clicked.
58	+It is send if the user clicks on a block and looks like this:
59	+
60	+Example:
61	+------------------------------------------
62	+{
63	+ "command": "block_clicked",
64	+ "name": "ethernet",
65	+ "instance": "eth0",
66	+ "x": 1320,
67	+ "y": 1400
68	+}
69	+------------------------------------------

74	@@ -33,6 +33,12 @@ typedef struct {
75	* The signal requested by the client to inform it of theun hidden state of i3bar
76	*/
77	int cont_signal;
78	+
79	+ /**
80	+ * Enable bi-directional communication, i.e. on-click events
81	+ */
82	+ bool bidirectional;
83	+ int bidirectional_init;
84	} i3bar_child;
85
86	/*
87	@@ -68,4 +74,10 @@ void stop_child(void);
88	*/
89	void cont_child(void);
90
91	+/*
92	+ * ends the block_clicked command to the child
93	+ *
94	+ */
95	+void send_block_clicked(const char name, const char instance, int x, int y);
96	+
97	#endif