screencast: add outputchooser with config option

Supports "dmenu" chooser type, which is called with a dmenu type list
piped to stdin, "simple" type, which recieves nothing on stdin and
default, which tries the hardcoded choosers.
Choosers are required to return the name of the choosen output as given
by the xdg-output protocol.

Thanks to piater for closing overlooked pipes.
Thanks to ericonr for suggestions regarding fork and pipes.

contrib/config.sample

@@ -1,3 +1,5 @@
 [screencast]
 output_name=
 max_fps=30
+chooser_cmd="slurp -f %o -o"
+chooser_type=simple

include/config.h

@@ -2,12 +2,15 @@
 #define CONFIG_H
 
 #include "logger.h"
+#include "screencast_common.h"
 
 struct config_screencast {
 	char *output_name;
 	double max_fps;
 	char *exec_before;
 	char *exec_after;
+	char *chooser_cmd;
+	enum xdpw_chooser_types chooser_type;
 };
 
 struct xdpw_config {

include/screencast_common.h

@@ -22,6 +22,18 @@ enum source_types {
   WINDOW = 2,
 };
 
+enum xdpw_chooser_types {
+  XDPW_CHOOSER_DEFAULT,
+  XDPW_CHOOSER_NONE,
+  XDPW_CHOOSER_SIMPLE,
+  XDPW_CHOOSER_DMENU,
+};
+
+struct xdpw_output_chooser {
+	enum xdpw_chooser_types type;
+	char *cmd;
+};
+
 struct xdpw_frame_damage {
 	uint32_t x;
 	uint32_t y;
@@ -113,4 +125,6 @@ enum spa_video_format xdpw_format_pw_from_wl_shm(
 	struct xdpw_screencast_instance *cast);
 enum spa_video_format xdpw_format_pw_strip_alpha(enum spa_video_format format);
 
+enum xdpw_chooser_types get_chooser_type(const char *chooser_type);
+const char *chooser_type_str(enum xdpw_chooser_types chooser_type);
 #endif /* SCREENCAST_COMMON_H */

include/wlr_screencast.h

@@ -22,6 +22,7 @@ struct xdpw_wlr_output *xdpw_wlr_output_find_by_name(struct wl_list *output_list
 struct xdpw_wlr_output *xdpw_wlr_output_first(struct wl_list *output_list);
 struct xdpw_wlr_output *xdpw_wlr_output_find(struct xdpw_screencast_context *ctx,
 	struct wl_output *out, uint32_t id);
+struct xdpw_wlr_output *xdpw_wlr_output_chooser(struct xdpw_screencast_context *ctx);
 
 void xdpw_wlr_frame_free(struct xdpw_screencast_instance *cast);
 void xdpw_wlr_register_cb(struct xdpw_screencast_instance *cast);

src/core/config.c

@@ -1,6 +1,7 @@
 #include "config.h"
 #include "xdpw.h"
 #include "logger.h"
+#include "screencast_common.h"
 
 #include <dictionary.h>
 #include <stdio.h>
@@ -11,6 +12,8 @@
 
 void print_config(enum LOGLEVEL loglevel, struct xdpw_config *config) {
 	logprint(loglevel, "config: outputname  %s", config->screencast_conf.output_name);
+	logprint(loglevel, "config: chooser_cmd: %s\n", config->screencast_conf.chooser_cmd);
+	logprint(loglevel, "config: chooser_type: %s\n", chooser_type_str(config->screencast_conf.chooser_type));
 }
 
 // NOTE: calling finish_config won't prepare the config to be read again from config file
@@ -22,6 +25,7 @@ void finish_config(struct xdpw_config *config) {
 	free(&config->screencast_conf.output_name);
 	free(&config->screencast_conf.exec_before);
 	free(&config->screencast_conf.exec_after);
+	free(&config->screencast_conf.chooser_cmd);
 }
 
 static void getstring_from_conffile(dictionary *d,
@@ -53,19 +57,6 @@ static bool file_exists(const char *path) {
 	return path && access(path, R_OK) != -1;
 }
 
-static char *config_path(const char *prefix, const char *filename) {
-	if (!prefix || !prefix[0] || !filename || !filename[0]) {
-		return NULL;
-	}
-
-	char *config_folder = "xdg-desktop-portal-wlr";
-
-	size_t size = 3 + strlen(prefix) + strlen(config_folder) + strlen(filename);
-	char *path = calloc(size, sizeof(char));
-	snprintf(path, size, "%s/%s/%s", prefix, config_folder, filename);
-	return path;
-}
-
 static void config_parse_file(const char *configfile, struct xdpw_config *config) {
 	dictionary *d = NULL;
 	if (configfile) {
@@ -83,12 +74,32 @@ static void config_parse_file(const char *configfile, struct xdpw_config *config
 	getdouble_from_conffile(d, "screencast:max_fps", &config->screencast_conf.max_fps, 0);
 	getstring_from_conffile(d, "screencast:exec_before", &config->screencast_conf.exec_before, NULL);
 	getstring_from_conffile(d, "screencast:exec_after", &config->screencast_conf.exec_after, NULL);
+	getstring_from_conffile(d, "screencast:chooser_cmd", &config->screencast_conf.chooser_cmd, NULL);
+	if (!config->screencast_conf.chooser_type) {
+		char *chooser_type = NULL;
+		getstring_from_conffile(d, "screencast:chooser_type", &chooser_type, "default");
+		config->screencast_conf.chooser_type = get_chooser_type(chooser_type);
+		free(chooser_type);
+	}
 
 	iniparser_freedict(d);
 	logprint(DEBUG, "config: config file parsed");
 	print_config(DEBUG, config);
 }
 
+static char *config_path(const char *prefix, const char *filename) {
+	if (!prefix || !prefix[0] || !filename || !filename[0]) {
+		return NULL;
+	}
+
+	char *config_folder = "xdg-desktop-portal-wlr";
+
+	size_t size = 3 + strlen(prefix) + strlen(config_folder) + strlen(filename);
+	char *path = calloc(size, sizeof(char));
+	snprintf(path, size, "%s/%s/%s", prefix, config_folder, filename);
+	return path;
+}
+
 static char *get_config_path(void) {
 	const char *home = getenv("HOME");
 	size_t size_fallback = 1 + strlen(home) + strlen("/.config");

src/core/logger.c

@@ -28,7 +28,7 @@ enum LOGLEVEL get_loglevel(const char *level) {
 	}
 
 	fprintf(stderr, "Could not understand log level %s\n", level);
-	abort();
+	exit(1);
 }
 
 static const char *print_loglevel(enum LOGLEVEL loglevel) {

src/core/main.c

@@ -74,6 +74,7 @@ int main(int argc, char *argv[]) {
 			break;
 		case 'o':
 			config.screencast_conf.output_name = strdup(optarg);
+			config.screencast_conf.chooser_type = XDPW_CHOOSER_NONE;
 			break;
 		case 'c':
 			configfile = strdup(optarg);

src/screencast/screencast.c

@@ -77,7 +77,7 @@ void xdpw_screencast_instance_destroy(struct xdpw_screencast_instance *cast) {
 	free(cast);
 }
 
-int setup_outputs(struct xdpw_screencast_context *ctx, struct xdpw_session *sess, bool with_cursor) {
+bool setup_outputs(struct xdpw_screencast_context *ctx, struct xdpw_session *sess, bool with_cursor) {
 
 	struct xdpw_wlr_output *output, *tmp_o;
 	wl_list_for_each_reverse_safe(output, tmp_o, &ctx->output_list, link) {
@@ -86,19 +86,10 @@ int setup_outputs(struct xdpw_screencast_context *ctx, struct xdpw_session *sess
 	}
 
 	struct xdpw_wlr_output *out;
-	if (ctx->state->config->screencast_conf.output_name) {
-		out = xdpw_wlr_output_find_by_name(&ctx->output_list,
-				ctx->state->config->screencast_conf.output_name);
-		if (!out) {
-			logprint(ERROR, "wlroots: no such output");
-			abort();
-		}
-	} else {
-		out = xdpw_wlr_output_first(&ctx->output_list);
-		if (!out) {
-			logprint(ERROR, "wlroots: no output found");
-			abort();
-		}
+	out = xdpw_wlr_output_chooser(ctx);
+	if (!out) {
+		logprint(ERROR, "wlroots: no output found");
+		return false;
 	}
 
 	struct xdpw_screencast_instance *cast, *tmp_c;
@@ -130,7 +121,7 @@ int setup_outputs(struct xdpw_screencast_context *ctx, struct xdpw_session *sess
 	logprint(INFO, "wlroots: output: %s",
 		sess->screencast_instance->target_output->name);
 
-	return 0;
+	return true;
 
 }
 
@@ -310,22 +301,23 @@ static int method_screencast_select_sources(sd_bus_message *msg, void *data,
 		return ret;
 	}
 
-	ret = -1;
+	bool output_selection_canceled = 1;
 	wl_list_for_each_reverse_safe(sess, tmp_s, &state->xdpw_sessions, link) {
 		if (strcmp(sess->session_handle, session_handle) == 0) {
 				logprint(DEBUG, "dbus: select sources: found matching session %s", sess->session_handle);
-				ret = setup_outputs(ctx, sess, cursor_embedded);
+				output_selection_canceled = !setup_outputs(ctx, sess, cursor_embedded);
 		}
 	}
-	if (ret < 0) {
-		return ret;
-	}
 
 	ret = sd_bus_message_new_method_return(msg, &reply);
 	if (ret < 0) {
 		return ret;
 	}
-	ret = sd_bus_message_append(reply, "ua{sv}", PORTAL_RESPONSE_SUCCESS, 0);
+	if (output_selection_canceled) {
+		ret = sd_bus_message_append(reply, "ua{sv}", PORTAL_RESPONSE_CANCELLED, 0);
+	} else {
+		ret = sd_bus_message_append(reply, "ua{sv}", PORTAL_RESPONSE_SUCCESS, 0);
+	}
 	if (ret < 0) {
 		return ret;
 	}

src/screencast/screencast_common.c

@@ -52,3 +52,32 @@ enum spa_video_format xdpw_format_pw_strip_alpha(enum spa_video_format format) {
 		return SPA_VIDEO_FORMAT_UNKNOWN;
 	}
 }
+
+enum xdpw_chooser_types get_chooser_type(const char *chooser_type) {
+	if (!chooser_type || strcmp(chooser_type, "default") == 0) {
+		return XDPW_CHOOSER_DEFAULT;
+	} else if (strcmp(chooser_type, "none") == 0) {
+		return XDPW_CHOOSER_NONE;
+	} else if (strcmp(chooser_type, "simple") == 0) {
+		return XDPW_CHOOSER_SIMPLE;
+	} else if (strcmp(chooser_type, "dmenu") == 0) {
+		return XDPW_CHOOSER_DMENU;
+	}
+	fprintf(stderr, "Could not understand chooser type %s\n", chooser_type);
+	exit(1);
+}
+
+const char *chooser_type_str(enum xdpw_chooser_types chooser_type) {
+	switch (chooser_type) {
+	case XDPW_CHOOSER_DEFAULT:
+		return "default";
+	case XDPW_CHOOSER_NONE:
+		return "none";
+	case XDPW_CHOOSER_SIMPLE:
+		return "simple";
+	case XDPW_CHOOSER_DMENU:
+		return "dmenu";
+	}
+	fprintf(stderr, "Could not find chooser type %d\n", chooser_type);
+	abort();
+}