#164 render a brief change message to set as $WD_MESSAGE for the command

inc/displ.h

@@ -35,6 +35,8 @@ struct Displ {
 	char *zxdg_output_manager_interface;
 
 	enum ConfigState config_state;
+
+	char *delta_message;
 };
 
 void displ_init(void);

inc/info.h

@@ -5,6 +5,7 @@
 #include <stddef.h>
 
 #include "cfg.h"
+#include "displ.h"
 #include "head.h"
 #include "slist.h"
 #include "log.h"
@@ -35,5 +36,8 @@ void info_user_mode_string(struct UserMode *user_mode, char *buf, size_t nbuf);
 
 void info_mode_string(struct Mode *mode, char *buf, size_t nbuf);
 
+// length 1024 * 64, consumer frees
+char *render_deltas_brief(const enum ConfigState config_state, const struct SList * const heads);
+
 #endif // INFO_H
 

src/info.c

@@ -1,5 +1,6 @@
 #include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <wayland-util.h>
 
 #include "info.h"
@@ -443,3 +444,84 @@ void print_heads(enum LogThreshold t, enum InfoEvent event, struct SList *heads)
 	}
 }
 
+char *render_deltas_brief(const enum ConfigState config_state, const struct SList * const heads) {
+	if (!heads) {
+		return NULL;
+	}
+
+	static const int len = 1024 * 64;
+
+	char *buf = (char*)calloc(len, sizeof(char));
+	char *bufp = buf;
+
+	for (const struct SList *i = heads; i; i = i->nex) {
+		const struct Head * head = i->val;
+
+		if (head->current.enabled && !head->desired.enabled) {
+			bufp += snprintf(bufp, len - (bufp - buf), "%s: disabled\n", head->name);
+			continue;
+		}
+
+		// mode changes happen in their own operation
+		if (head_current_mode_not_desired(head)) {
+			bufp += snprintf(bufp, len - (bufp - buf), "%s%s:\n  mode: %dx%d@%dHz -> %dx%d@%dHz\n", // line up with vrr
+					head->name,
+					(!head->current.enabled && head->desired.enabled) ? ": enabled" : "",
+					head->current.mode->width,
+					head->current.mode->height,
+					mhz_to_hz_rounded(head->current.mode->refresh_mhz),
+					head->desired.mode->width,
+					head->desired.mode->height,
+					mhz_to_hz_rounded(head->desired.mode->refresh_mhz)
+					);
+			continue;
+		}
+
+		if (!head->current.enabled && head->desired.enabled) {
+			bufp += snprintf(bufp, len - (bufp - buf), "%s: enabled\n", head->name);
+			continue;
+		}
+
+		// adaptive sync changes happen in their own operation
+		if (head_current_adaptive_sync_not_desired(head)) {
+			bufp += snprintf(bufp, len - (bufp - buf), "%s:\n  VRR:  %s\n", // line up with mode
+					head->name,
+					head->desired.adaptive_sync == ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_ENABLED ? "on" : "off"
+					);
+			continue;
+		}
+
+		if (head_current_not_desired(head)) {
+			bufp += snprintf(bufp, len - (bufp - buf), "%s:\n", head->name);
+
+			if (head->current.scale != head->desired.scale) {
+				bufp += snprintf(bufp, len - (bufp - buf), "  scale:     %.3f -> %.3f\n",
+						wl_fixed_to_double(head->current.scale),
+						wl_fixed_to_double(head->desired.scale)
+						);
+			}
+
+			if (head->current.transform != head->desired.transform) {
+				bufp += snprintf(bufp, len - (bufp - buf), "  transform: %s -> %s\n",
+						head->current.transform ? transform_name(head->current.transform) : "none",
+						head->desired.transform ? transform_name(head->desired.transform) : "none"
+						);
+			}
+
+			if (head->current.x != head->desired.x || head->current.y != head->desired.y) {
+				bufp += snprintf(bufp, len - (bufp - buf), "  position:  %d,%d -> %d,%d\n",
+						head->current.x, head->current.y,
+						head->desired.x, head->desired.y
+						);
+			}
+		}
+	}
+
+	// strip trailing newline
+	if (bufp > buf) {
+		*(bufp - 1) = '\0';
+	}
+
+	return buf;
+}
+

src/layout.c

@@ -327,6 +327,9 @@ void apply(void) {
 
 	zwlr_output_configuration_v1_apply(zwlr_config);
 
+	free(displ->delta_message);
+	displ->delta_message = render_deltas_brief(displ->config_state, heads_changing);
+
 	displ->config_state = OUTSTANDING;
 
 	slist_free(&heads_changing);
@@ -365,7 +368,7 @@ void handle_success(void) {
 		log_info("\nExecuting CHANGE_SUCCESS_CMD:");
 		log_info("  %s", cfg->change_success_cmd);
 
-		spawn_sh_cmd(cfg->change_success_cmd, "handle_success");
+		spawn_sh_cmd(cfg->change_success_cmd, displ->delta_message);
 	}
 
 	log_info("\nChanges successful");
@@ -435,6 +438,9 @@ void layout(void) {
 			break;
 	}
 
+	free(displ->delta_message);
+	displ->delta_message = NULL;
+
 	desire();
 	apply();
 }

src/process.c

@@ -4,6 +4,7 @@
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/file.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -105,9 +106,13 @@ void pid_file_create(void) {
 }
 
 void spawn_sh_cmd(const char * const command, char * const message) {
+	if (!command || !message)
+		return;
 
 	// experiments show that environment variable length tops out at 128k: variable itself plus contents
-	// message[1024 * 120] = '\0';
+	if (strlen(message) > 1024 * 120) {
+		message[1024 * 120] = '\0';
+	}
 
 	pid_t pid = fork();
 	if (pid < 0) {

tst/info/print-head-arrived-all.log

@@ -1,11 +1,11 @@
 
-name Arrived:
+name1 Arrived:
   info:
-    name:      'name'
-    make:      'make'
-    model:     'model'
-    serial:    'serial_number'
-    desc:      'description'
+    name:      'name1'
+    make:      'make1'
+    model:     'model1'
+    serial:    'serial_number1'
+    desc:      'description1'
     width:     1mm
     height:    2mm
     dpi:       2540.00 @ 100x200

tst/info/print-head-deltas-disable.log

@@ -1,5 +1,5 @@
 
-name Changing:
+name1 Changing:
   from:
     scale:     2.000 (26.458)
     position:  700,800

tst/info/print-head-deltas-enable.log

@@ -1,5 +1,5 @@
 
-name Changing:
+name1 Changing:
   from:
     mode:      100x200@30Hz (30,000mHz) (preferred)
     VRR:       off

tst/info/print-head-deltas-mode.log

@@ -1,5 +1,5 @@
 
-name Changing:
+name1 Changing:
   from:
     scale:     2.000 (26.458)
     position:  700,800

tst/info/print-head-deltas-other.log

@@ -1,5 +1,5 @@
 
-name Changing:
+name1 Changing:
   from:
     scale:     2.000 (26.458)
     position:  700,800

tst/info/print-head-deltas-vrr.log

@@ -1,5 +1,5 @@
 
-name Changing:
+name1 Changing:
   from:
     scale:     2.000 (26.458)
     position:  700,800

tst/info/print-head-departed-ok.log

@@ -1,5 +1,5 @@
 
-name Departed:
-    name:      'name'
-    desc:      'description'
+name1 Departed:
+    name:      'name1'
+    desc:      'description1'