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Add optional bidirectional interface to i3bar.

Patch status: superseded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))

To apply this patch, use:
curl http://cr.i3wm.org/patch/69/raw.patch | git am

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);
 
+/*
+ * sends a command to the child, if bidirectional communication is enabled.
+ *
+ */
+void send_child_command(const char *command, const char *name, const char *instance);
+
 #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 +428,38 @@ void start_child(char *command) {
 }
 
 /*
+ * sends a command to the child, if bidirectional communication is enabled.
+ *
+ */
+void send_child_command(const char *command, const char *name, const char *instance) {
+    if(child.bidirectional) {
+        if(!child.bidirectional_init) {
+            yajl_gen_array_open(gen);
+            child_write_output();
+            child.bidirectional_init = 1;
+        }
+        yajl_gen_map_open(gen);
+
+        yajl_gen_string(gen, (const unsigned char *)"command", strlen("command"));
+        yajl_gen_string(gen, (const unsigned char *)command, strlen(command));
+
+        if(name) {
+            yajl_gen_string(gen, (const unsigned char *)"name", strlen("name"));
+            yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
+        }
+
+        if(instance) {
+            yajl_gen_string(gen, (const unsigned char *)"instance", strlen("instance"));
+            yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
+        }
+
+        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 +322,40 @@ 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);
+                }
+
+                /* Since we iterated over *all* buttons above (else we won't be here)
+                   we can calculate this width easily */
+                int workspace_button_width = (original_x - x);
+
+                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_child_command("block_clicked", block->name, block->instance);
+                        break;
+                    }
+                }
                 return;
             }
             break;

69	@@ -21,6 +21,7 @@
70	#include <yajl/yajl_common.h>
71	#include <yajl/yajl_parse.h>
72	#include <yajl/yajl_version.h>
73	+#include <yajl/yajl_gen.h>
74
75	#include "common.h"
76
77	@@ -35,6 +36,9 @@ ev_child *child_sig;
78	yajl_callbacks callbacks;
79	yajl_handle parser;
80
81	+/* JSON generator for stdout */
82	+yajl_gen gen;
83	+
84	typedef struct parser_ctx {
85	/* True if one of the parsed blocks was urgent */
86	bool has_urgent;
87	@@ -141,6 +145,18 @@ static int stdin_string(void context, const unsigned char val, unsigned int le
88	ctx->block.align = ALIGN_CENTER;
89	}
90	}
91	+ if (strcasecmp(ctx->last_map_key, "name") == 0) {
92	+ char copy = (char)malloc(len+1);
93	+ strncpy(copy, (const char *)val, len);
94	+ copy[len] = 0;
95	+ ctx->block.name = copy;
96	+ }
97	+ if (strcasecmp(ctx->last_map_key, "instance") == 0) {
98	+ char copy = (char)malloc(len+1);
99	+ strncpy(copy, (const char *)val, len);
100	+ copy[len] = 0;
101	+ ctx->block.instance = copy;
102	+ }
103	return 1;
104	}
105
106	@@ -322,6 +338,18 @@ void child_sig_cb(struct ev_loop loop, ev_child watcher, int revents) {
107	cleanup();
108	}
109
110	+void child_write_output(void) {
111	+ if(child.bidirectional) {
112	+ const unsigned char *output;
113	+ size_t size;
114	+ yajl_gen_get_buf(gen, &output, &size);
115	+ fwrite(output, 1, size, stdout);
116	+ fwrite("\n", 1, 1, stdout);
117	+ fflush(stdout);
118	+ yajl_gen_clear(gen);
119	+ }
120	+}
121	+
122	/*
123	* Start a child-process with the specified command and reroute stdin.
124	* We actually start a $SHELL to execute the command so we don't have to care
125	@@ -347,10 +375,14 @@ void start_child(char *command) {
126	parser = yajl_alloc(&callbacks, NULL, &parser_context);
127	#endif
128
129	+ gen = yajl_gen_alloc(NULL);
130	+
131	if (command != NULL) {
132	- int fd[2];
133	+ int fd[4];
134	if (pipe(fd) == -1)
135	err(EXIT_FAILURE, "pipe(fd)");
136	+ if (pipe(&fd[2]) == -1)
137	+ err(EXIT_FAILURE, "pipe(fd)");
138
139	child.pid = fork();
140	switch (child.pid) {
141	@@ -358,10 +390,10 @@ void start_child(char *command) {
142	ELOG("Couldn't fork(): %s\n", strerror(errno));
143	exit(EXIT_FAILURE);
144	case 0:
145	- /* Child-process. Reroute stdout and start shell */
146	- close(fd[0]);
147	+ /* Child-process. Reroute streams and start shell */
148
149	dup2(fd[1], STDOUT_FILENO);
150	+ dup2(fd[2], STDIN_FILENO);
151
152	static const char *shell = NULL;
153
154	@@ -371,9 +403,9 @@ void start_child(char *command) {
155	execl(shell, shell, "-c", command, (char*) NULL);
156	return;
157	default:
158	- /* Parent-process. Rerout stdin */
159	- close(fd[1]);
160	+ /* Parent-process. Reroute streams */
161
162	+ dup2(fd[3], STDOUT_FILENO);
163	dup2(fd[0], STDIN_FILENO);
164
165	break;
166	@@ -396,6 +428,38 @@ void start_child(char *command) {
167	}
168
169	/*
170	+ * sends a command to the child, if bidirectional communication is enabled.
171	+ *
172	+ */
173	+void send_child_command(const char command, const char name, const char *instance) {
174	+ if(child.bidirectional) {
175	+ if(!child.bidirectional_init) {
176	+ yajl_gen_array_open(gen);
177	+ child_write_output();
178	+ child.bidirectional_init = 1;
179	+ }
180	+ yajl_gen_map_open(gen);
181	+
182	+ yajl_gen_string(gen, (const unsigned char *)"command", strlen("command"));
183	+ yajl_gen_string(gen, (const unsigned char *)command, strlen(command));
184	+
185	+ if(name) {
186	+ yajl_gen_string(gen, (const unsigned char *)"name", strlen("name"));
187	+ yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
188	+ }
189	+
190	+ if(instance) {
191	+ yajl_gen_string(gen, (const unsigned char *)"instance", strlen("instance"));
192	+ yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
193	+ }
194	+
195	+ yajl_gen_map_close(gen);
196	+
197	+ child_write_output();
198	+ }
199	+}
200	+
201	+/*
202	* kill()s the child-process (if any). Called when exit()ing.
203	*
204	*/

209	@@ -31,6 +31,7 @@ static enum {
210	KEY_VERSION,
211	KEY_STOP_SIGNAL,
212	KEY_CONT_SIGNAL,
213	+ KEY_BIDIRECTIONAL,
214	NO_KEY
215	} current_key;
216
217	@@ -51,6 +52,8 @@ static int header_integer(void *ctx, long val) {
218	case KEY_CONT_SIGNAL:
219	child->cont_signal = val;
220	break;
221	+ case KEY_BIDIRECTIONAL:
222	+ child->bidirectional = val;
223	default:
224	break;
225	}
226	@@ -71,6 +74,8 @@ static int header_map_key(void ctx, const unsigned char stringval, unsigned in
227	current_key = KEY_STOP_SIGNAL;
228	} else if (CHECK_KEY("cont_signal")) {
229	current_key = KEY_CONT_SIGNAL;
230	+ } else if (CHECK_KEY("bidirectional")) {
231	+ current_key = KEY_BIDIRECTIONAL;
232	}
233	return 1;
234	}

239	@@ -160,7 +160,7 @@ void refresh_statusline(void) {
240	xcb_poly_fill_rectangle(xcb_connection, statusline_pm, statusline_clear, 1, &rect);
241
242	/* Draw the text of each block. */
243	- uint32_t x = 0;
244	+ uint32_t x = 0;
245	TAILQ_FOREACH(block, &statusline_head, blocks) {
246	if (i3string_get_num_bytes(block->full_text) == 0)
247	continue;
248	@@ -306,6 +306,7 @@ void handle_button(xcb_button_press_event_t *event) {
249	}
250
251	int32_t x = event->event_x >= 0 ? event->event_x : 0;
252	+ int32_t original_x = x;
253
254	DLOG("Got Button %d\n", event->detail);
255
256	@@ -321,6 +322,40 @@ void handle_button(xcb_button_press_event_t *event) {
257	x -= cur_ws->name_width + 11;
258	}
259	if (cur_ws == NULL) {
260	+ /* No workspace button was pressed.
261	+ * Check if a status block has been clicked.
262	+ * This of course only has an effect,
263	+ * if the child reported bidirectional protocol usage. */
264	+
265	+ /* First calculate width of tray area */
266	+ trayclient *trayclient;
267	+ int tray_width = 0;
268	+ TAILQ_FOREACH_REVERSE(trayclient, walk->trayclients, tc_head, tailq) {
269	+ if (!trayclient->mapped)
270	+ continue;
271	+ tray_width += (font.height + 2);
272	+ }
273	+
274	+ /* Since we iterated over all buttons above (else we won't be here)
275	+ we can calculate this width easily */
276	+ int workspace_button_width = (original_x - x);
277	+
278	+ int block_x = 0, last_block_x;
279	+ int offset = (walk->rect.w - (statusline_width + tray_width)) - 10;
280	+
281	+ x = original_x - offset > 0 ? original_x - offset : 0;
282	+
283	+ struct status_block *block;
284	+
285	+ TAILQ_FOREACH(block, &statusline_head, blocks) {
286	+ last_block_x = block_x;
287	+ block_x += block->width + block->x_offset + block->x_append;
288	+
289	+ if(x <= block_x && x >= last_block_x) {
290	+ send_child_command("block_clicked", block->name, block->instance);
291	+ break;
292	+ }
293	+ }
294	return;
295	}
296	break;

26	@@ -33,6 +33,12 @@ typedef struct {
27	* The signal requested by the client to inform it of theun hidden state of i3bar
28	*/
29	int cont_signal;
30	+
31	+ /**
32	+ * Enable bi-directional communication, i.e. on-click events
33	+ */
34	+ bool bidirectional;
35	+ int bidirectional_init;
36	} i3bar_child;
37
38	/*
39	@@ -68,4 +74,10 @@ void stop_child(void);
40	*/
41	void cont_child(void);
42
43	+/*
44	+ * sends a command to the child, if bidirectional communication is enabled.
45	+ *
46	+ */
47	+void send_child_command(const char command, const char name, const char *instance);
48	+
49	#endif

54	@@ -50,6 +50,10 @@ struct status_block {
55	uint32_t x_offset;
56	uint32_t x_append;
57
58	+ /* Optional */
59	+ char *name;
60	+ char *instance;
61	+
62	TAILQ_ENTRY(status_block) blocks;
63	};
64