Add opt-in session save and restore support

assets/config.conf

@@ -78,6 +78,17 @@ no_border_when_single=0
 axis_bind_apply_timeout=100
 focus_on_activate=1
 idleinhibit_ignore_visible=0
+# Restore and save session state across compositor restarts.
+# Disabled by default to preserve Mango's current behavior.
+# Minimized restore is currently unsupported.
+# Restore expects target outputs to already exist before clients map.
+session_restore=0
+# Relaunch mapping used when Mango cannot infer a launch command from a client.
+# Format: session_launch=app_id|command
+#    or: session_launch=app_id|title|command
+# session_launch=foot|foot
+# session_launch=foot|gamma|foot -a foot -T gamma -e sh -lc "sleep 600"
+# session_launch=org.kde.dolphin|dolphin .
 sloppyfocus=1
 warpcursor=1
 focus_cross_monitor=0

meson.build

@@ -97,6 +97,7 @@ endif
 executable('mango',
   'src/mango.c',
   'src/common/util.c',
+  'src/session/session.c',
   'src/ext-protocol/wlr_ext_workspace_v1.c',
   wayland_sources,
   dependencies : [

src/config/parse_config.h

@@ -52,6 +52,12 @@ typedef struct {
 	char *value;
 } ConfigEnv;
 
+typedef struct {
+	char app_id[256];
+	char title[512];
+	char command[1024];
+} ConfigSessionLaunchRule;
+
 typedef struct {
 	const char *id;
 	const char *title;
@@ -251,6 +257,7 @@ typedef struct {
 
 	uint32_t axis_bind_apply_timeout;
 	uint32_t focus_on_activate;
+	int32_t session_restore;
 	int32_t idleinhibit_ignore_visible;
 	int32_t sloppyfocus;
 	int32_t warpcursor;
@@ -352,6 +359,8 @@ typedef struct {
 
 	char **exec_once;
 	int32_t exec_once_count;
+	ConfigSessionLaunchRule *session_launch_rules;
+	int32_t session_launch_rules_count;
 
 	char *cursor_theme;
 	uint32_t cursor_size;
@@ -1426,6 +1435,71 @@ bool parse_option(Config *config, char *key, char *value) {
 		config->allow_shortcuts_inhibit = atoi(value);
 	} else if (strcmp(key, "allow_lock_transparent") == 0) {
 		config->allow_lock_transparent = atoi(value);
+	} else if (strcmp(key, "session_restore") == 0) {
+		config->session_restore = atoi(value);
+	} else if (strcmp(key, "session_launch") == 0) {
+		ConfigSessionLaunchRule rule = {0};
+		ConfigSessionLaunchRule *new_rules = NULL;
+		char *first_sep = strchr(value, '|');
+		char *second_sep = NULL;
+		size_t app_len, title_len = 0, cmd_len;
+
+		if (!first_sep) {
+			fprintf(stderr,
+					"\033[1m\033[31m[ERROR]:\033[33m Invalid session_launch "
+					"format. Expected app_id|command or "
+					"app_id|title|command\033[0m\n");
+			return false;
+		}
+
+		second_sep = strchr(first_sep + 1, '|');
+		app_len = (size_t)(first_sep - value);
+		if (second_sep) {
+			title_len = (size_t)(second_sep - (first_sep + 1));
+			cmd_len = strlen(second_sep + 1);
+		} else {
+			cmd_len = strlen(first_sep + 1);
+		}
+
+		if (app_len == 0 || cmd_len == 0 || app_len >= sizeof(rule.app_id) ||
+			cmd_len >= sizeof(rule.command) ||
+			title_len >= sizeof(rule.title)) {
+			fprintf(stderr,
+					"\033[1m\033[31m[ERROR]:\033[33m Invalid session_launch "
+					"entry length\033[0m\n");
+			return false;
+		}
+
+		memcpy(rule.app_id, value, app_len);
+		rule.app_id[app_len] = '\0';
+		if (second_sep) {
+			memcpy(rule.title, first_sep + 1, title_len);
+			rule.title[title_len] = '\0';
+			memcpy(rule.command, second_sep + 1, cmd_len + 1);
+		} else {
+			memcpy(rule.command, first_sep + 1, cmd_len + 1);
+		}
+		trim_whitespace(rule.app_id);
+		trim_whitespace(rule.title);
+		trim_whitespace(rule.command);
+		if (rule.app_id[0] == '\0' || rule.command[0] == '\0') {
+			fprintf(stderr,
+					"\033[1m\033[31m[ERROR]:\033[33m session_launch requires "
+					"both app_id and command\033[0m\n");
+			return false;
+		}
+
+		new_rules = realloc(config->session_launch_rules,
+							sizeof(*config->session_launch_rules) *
+								(config->session_launch_rules_count + 1));
+		if (!new_rules) {
+			fprintf(stderr,
+					"\033[1m\033[31m[ERROR]:\033[33m Failed to allocate "
+					"session_launch rules\033[0m\n");
+			return false;
+		}
+		config->session_launch_rules = new_rules;
+		config->session_launch_rules[config->session_launch_rules_count++] = rule;
 	} else if (strcmp(key, "no_border_when_single") == 0) {
 		config->no_border_when_single = atoi(value);
 	} else if (strcmp(key, "no_radius_when_single") == 0) {
@@ -2826,6 +2900,14 @@ void free_circle_layout(Config *config) {
 	config->circle_layout_count = 0; // 重置计数
 }
 
+void free_session_launch_rules(Config *config) {
+	if (config->session_launch_rules) {
+		free(config->session_launch_rules);
+		config->session_launch_rules = NULL;
+	}
+	config->session_launch_rules_count = 0;
+}
+
 void free_baked_points(void) {
 	if (baked_points_move) {
 		free(baked_points_move);
@@ -3096,6 +3178,7 @@ void free_config(void) {
 
 	// 释放 circle_layout
 	free_circle_layout(&config);
+	free_session_launch_rules(&config);
 
 	// 释放动画资源
 	free_baked_points();
@@ -3171,6 +3254,7 @@ void override_config(void) {
 	config.axis_bind_apply_timeout =
 		CLAMP_INT(config.axis_bind_apply_timeout, 0, 1000);
 	config.focus_on_activate = CLAMP_INT(config.focus_on_activate, 0, 1);
+	config.session_restore = CLAMP_INT(config.session_restore, 0, 1);
 	config.idleinhibit_ignore_visible =
 		CLAMP_INT(config.idleinhibit_ignore_visible, 0, 1);
 	config.sloppyfocus = CLAMP_INT(config.sloppyfocus, 0, 1);
@@ -3275,6 +3359,9 @@ void set_value_default() {
 
 	config.axis_bind_apply_timeout = 100;
 	config.focus_on_activate = 1;
+	config.session_restore = 0;
+	config.session_launch_rules = NULL;
+	config.session_launch_rules_count = 0;
 	config.new_is_master = 1;
 	config.default_mfact = 0.55f;
 	config.default_nmaster = 1;
@@ -3511,6 +3598,8 @@ bool parse_config(void) {
 	config.exec_count = 0;
 	config.exec_once = NULL;
 	config.exec_once_count = 0;
+	config.session_launch_rules = NULL;
+	config.session_launch_rules_count = 0;
 	config.scroller_proportion_preset = NULL;
 	config.scroller_proportion_preset_count = 0;
 	config.circle_layout = NULL;

src/mango.c

@@ -407,6 +407,7 @@ struct Client {
 	float focused_opacity;
 	float unfocused_opacity;
 	char oldmonname[128];
+	char session_launch_command[1024];
 	int32_t noblur;
 	double master_mfact_per, master_inner_per, stack_inner_per;
 	double old_master_mfact_per, old_master_inner_per, old_stack_inner_per;
@@ -941,6 +942,7 @@ struct Pertag {
 };
 
 #include "config/parse_config.h"
+#include "session/session.h"
 
 static struct wl_signal mango_print_status;
 
@@ -1011,6 +1013,257 @@ static struct wl_event_source *sync_keymap;
 #include "layout/horizontal.h"
 #include "layout/vertical.h"
 
+static void session_write_json_string(FILE *out, const char *str) {
+	const unsigned char *p = (const unsigned char *)(str ? str : "");
+
+	fputc('"', out);
+	for (; *p != '\0'; ++p) {
+		switch (*p) {
+		case '\\':
+			fputs("\\\\", out);
+			break;
+		case '"':
+			fputs("\\\"", out);
+			break;
+		case '\n':
+			fputs("\\n", out);
+			break;
+		case '\r':
+			fputs("\\r", out);
+			break;
+		case '\t':
+			fputs("\\t", out);
+			break;
+		default:
+			if (*p < 0x20)
+				fprintf(out, "\\u%04x", *p);
+			else
+				fputc(*p, out);
+		}
+	}
+	fputc('"', out);
+}
+
+const char *mango_session_client_appid(Client *c) { return client_get_appid(c); }
+
+const char *mango_session_client_title(Client *c) { return client_get_title(c); }
+
+const char *mango_session_client_monitor(Client *c) {
+	return (c && c->mon && c->mon->wlr_output) ? c->mon->wlr_output->name : "";
+}
+
+const char *mango_session_lookup_launch_command(const char *app_id,
+												const char *title) {
+	if (!app_id || app_id[0] == '\0')
+		return "";
+
+	for (int32_t i = 0; i < config.session_launch_rules_count; ++i) {
+		ConfigSessionLaunchRule *rule = &config.session_launch_rules[i];
+		if (strcmp(rule->app_id, app_id) != 0)
+			continue;
+		if (rule->title[0] == '\0')
+			continue;
+		if (title && strcmp(rule->title, title) == 0)
+			return rule->command;
+	}
+
+	for (int32_t i = 0; i < config.session_launch_rules_count; ++i) {
+		ConfigSessionLaunchRule *rule = &config.session_launch_rules[i];
+		if (strcmp(rule->app_id, app_id) == 0 && rule->title[0] == '\0')
+			return rule->command;
+	}
+
+	return "";
+}
+
+void mango_session_remember_client_launch_command(Client *c, const char *command) {
+	if (!c)
+		return;
+
+	memset(c->session_launch_command, 0, sizeof(c->session_launch_command));
+	if (!command || command[0] == '\0')
+		return;
+
+	strncpy(c->session_launch_command, command,
+			sizeof(c->session_launch_command) - 1);
+	c->session_launch_command[sizeof(c->session_launch_command) - 1] = '\0';
+}
+
+void mango_session_spawn_command(const char *command) {
+	if (!command || command[0] == '\0')
+		return;
+
+	if (fork() == 0) {
+		signal(SIGSEGV, SIG_IGN);
+		signal(SIGABRT, SIG_IGN);
+		signal(SIGILL, SIG_IGN);
+
+		dup2(STDERR_FILENO, STDOUT_FILENO);
+		setsid();
+
+		execlp("sh", "sh", "-c", command, (char *)NULL);
+		execlp("bash", "bash", "-c", command, (char *)NULL);
+		_exit(EXIT_FAILURE);
+	}
+}
+
+static bool session_client_should_save(Client *c) {
+	const char *appid;
+
+	if (!c || c->iskilling || !c->mon || c->tags == 0)
+		return false;
+	if (client_is_unmanaged(c) || client_is_x11_popup(c))
+		return false;
+	if (client_get_parent(c) != NULL)
+		return false;
+	if (c->is_in_scratchpad || c->is_scratchpad_show || c->isnamedscratchpad)
+		return false;
+	if (c->swallowing || c->swallowedby)
+		return false;
+
+	appid = client_get_appid(c);
+	return appid && appid[0] != '\0' && strcmp(appid, "broken") != 0;
+}
+
+int32_t mango_session_is_config_enabled(void) { return config.session_restore; }
+
+static const char *session_client_launch_command(Client *c) {
+	const char *appid;
+	const char *title;
+	const char *mapped_command;
+
+	if (c && c->session_launch_command[0] != '\0')
+		return c->session_launch_command;
+
+	appid = client_get_appid(c);
+
+	if (!appid || appid[0] == '\0' || strcmp(appid, "broken") == 0)
+		return "";
+
+	title = client_get_title(c);
+	mapped_command = mango_session_lookup_launch_command(appid, title);
+	if (mapped_command && mapped_command[0] != '\0')
+		return mapped_command;
+
+	/* First relaunch pass: use app_id as the best-effort launch command.
+	 * Explicit config mappings will override this for wrappers and PWAs. */
+	return appid;
+}
+
+int32_t mango_session_write_snapshot(FILE *out) {
+	Client *c;
+	int32_t count = 0;
+
+	fputs("[\n", out);
+	wl_list_for_each(c, &clients, link) {
+		const char *monitor_name;
+		const char *appid;
+		const char *launch_command;
+		const char *title;
+		const char *separator;
+
+		if (!session_client_should_save(c))
+			continue;
+
+		monitor_name =
+			(c->mon && c->mon->wlr_output) ? c->mon->wlr_output->name : "";
+		appid = client_get_appid(c);
+		launch_command = session_client_launch_command(c);
+		title = client_get_title(c);
+		separator = count == 0 ? "" : ",\n";
+
+		fputs(separator, out);
+		fputs("  {\n", out);
+		fputs("    \"app_id\": ", out);
+		session_write_json_string(out, appid);
+		fputs(",\n    \"title\": ", out);
+		session_write_json_string(out, title);
+		fprintf(out,
+				",\n    \"pid\": %d,\n    \"monitor\": ",
+				client_get_pid(c));
+		session_write_json_string(out, monitor_name);
+		fputs(",\n    \"launch_command\": ", out);
+		session_write_json_string(out, launch_command);
+		fprintf(out,
+				",\n    \"tags\": %u,\n    \"is_floating\": %d,\n    "
+				"\"is_fullscreen\": %d,\n    \"is_minimized\": %d,\n    "
+				"\"geom\": {\"x\": %d, \"y\": %d, \"width\": %d, \"height\": %d},"
+				"\n    \"float_geom\": {\"x\": %d, \"y\": %d, \"width\": %d, "
+				"\"height\": %d}\n  }",
+				c->tags, c->isfloating, c->isfullscreen, c->isminimized, c->geom.x,
+				c->geom.y, c->geom.width, c->geom.height, c->float_geom.x,
+				c->float_geom.y, c->float_geom.width, c->float_geom.height);
+		count++;
+	}
+	fputs("\n]\n", out);
+
+	return count;
+}
+
+void mango_session_apply_restore_entry(Client *c,
+									   const SessionRestoreEntry *entry) {
+	Monitor *target = NULL, *m = NULL;
+	uint32_t tags;
+
+	if (!c || !entry || !c->mon)
+		return;
+
+	tags = entry->tags;
+	if (tags == 0)
+		tags = c->tags ? c->tags : c->mon->tagset[c->mon->seltags];
+
+	if (entry->monitor[0] != '\0') {
+		wl_list_for_each(m, &mons, link) {
+			if (!m->wlr_output->enabled)
+				continue;
+			if (strcmp(m->wlr_output->name, entry->monitor) == 0) {
+				target = m;
+				break;
+			}
+		}
+	}
+
+	if (target && target != c->mon) {
+		setmon(c, target, tags, false);
+	} else {
+		c->tags = tags;
+	}
+
+	arrange(c->mon, false, false);
+
+	if (entry->is_floating) {
+		c->float_geom = (struct wlr_box){
+			.x = entry->float_geom.x,
+			.y = entry->float_geom.y,
+			.width = entry->float_geom.width,
+			.height = entry->float_geom.height,
+		};
+		if (c->float_geom.width <= 0 || c->float_geom.height <= 0) {
+			c->float_geom = (struct wlr_box){
+				.x = entry->geom.x,
+				.y = entry->geom.y,
+				.width = entry->geom.width,
+				.height = entry->geom.height,
+			};
+		}
+		c->geom = c->float_geom;
+		setfloating(c, 1);
+		resize(c, c->geom, 0);
+	} else if (c->isfloating) {
+		setfloating(c, 0);
+	}
+
+	if (entry->is_fullscreen && !c->isfullscreen) {
+		setfullscreen(c, 1);
+	} else if (!entry->is_fullscreen && c->isfullscreen) {
+		setfullscreen(c, 0);
+	}
+
+	/* Skip minimized restore for now to avoid introducing new focus changes. */
+	client_update_oldmonname_record(c, c->mon);
+	printstatus();
+}
+
 void client_change_mon(Client *c, Monitor *m) {
 	setmon(c, m, c->tags, true);
 	if (c->isfloating) {
@@ -2264,6 +2517,8 @@ void cleanuplisteners(void) {
 }
 
 void cleanup(void) {
+	session_save_now(true);
+	session_shutdown();
 	cleanuplisteners();
 #ifdef XWAYLAND
 	wlr_xwayland_destroy(xwayland);
@@ -4208,6 +4463,7 @@ mapnotify(struct wl_listener *listener, void *data) {
 	// make sure the animation is open type
 	c->is_pending_open_animation = true;
 	resize(c, c->geom, 0);
+	session_handle_client_mapped(c);
 	printstatus();
 }
 
@@ -4978,6 +5234,7 @@ run(char *startup_cmd) {
 
 	run_exec();
 	run_exec_once();
+	session_maybe_restore_startup();
 
 	/* Run the Wayland event loop. This does not return until you exit the
 	 * compositor. Starting the backend rigged up all of the necessary event
@@ -5494,6 +5751,7 @@ void setup(void) {
 	setenv("_JAVA_AWT_WM_NONREPARENTING", "1", 1);
 
 	parse_config();
+	session_init();
 	if (cli_debug_log) {
 		config.log_level = WLR_DEBUG;
 	}

src/session/session.c

@@ -0,0 +1,489 @@
+#include "session.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "../common/util.h"
+
+extern int32_t mango_session_is_config_enabled(void);
+extern int32_t mango_session_write_snapshot(FILE *out);
+extern const char *mango_session_client_appid(Client *c);
+extern const char *mango_session_client_title(Client *c);
+extern const char *mango_session_client_monitor(Client *c);
+extern const char *mango_session_lookup_launch_command(const char *app_id,
+													   const char *title);
+extern void mango_session_remember_client_launch_command(Client *c,
+														 const char *command);
+extern void mango_session_spawn_command(const char *command);
+extern void mango_session_apply_restore_entry(Client *c,
+											  const SessionRestoreEntry *entry);
+
+typedef struct {
+	SessionRestoreEntry entry;
+	bool used;
+} PendingSessionEntry;
+
+static PendingSessionEntry *pending_entries;
+static size_t pending_count;
+static bool restore_started;
+
+static bool mkdir_p(const char *dir) {
+	char tmp[PATH_MAX];
+	size_t len;
+
+	if (!dir || dir[0] == '\0')
+		return false;
+
+	len = strlen(dir);
+	if (len >= sizeof(tmp))
+		return false;
+
+	memcpy(tmp, dir, len + 1);
+
+	for (char *p = tmp + 1; *p != '\0'; ++p) {
+		if (*p != '/')
+			continue;
+		*p = '\0';
+		if (mkdir(tmp, 0755) < 0 && errno != EEXIST)
+			return false;
+		*p = '/';
+	}
+
+	return mkdir(tmp, 0755) == 0 || errno == EEXIST;
+}
+
+static char *session_data_dir(void) {
+	const char *xdg_data = getenv("XDG_DATA_HOME");
+	if (xdg_data && xdg_data[0] != '\0')
+		return string_printf("%s/mango", xdg_data);
+
+	const char *home = getenv("HOME");
+	if (!home || home[0] == '\0')
+		return NULL;
+
+	return string_printf("%s/.local/share/mango", home);
+}
+
+static char *session_file_path(void) {
+	char *dir = session_data_dir();
+	char *path;
+	if (!dir)
+		return NULL;
+	path = string_printf("%s/session.json", dir);
+	free(dir);
+	return path;
+}
+
+static void free_pending_entries(void) {
+	free(pending_entries);
+	pending_entries = NULL;
+	pending_count = 0;
+}
+
+static const char *skip_ws(const char *p) {
+	while (p && (*p == ' ' || *p == '\n' || *p == '\r' || *p == '\t'))
+		++p;
+	return p;
+}
+
+static const char *find_matching_brace(const char *start) {
+	int depth = 0;
+	bool in_string = false;
+	bool escaped = false;
+
+	for (const char *p = start; p && *p != '\0'; ++p) {
+		if (in_string) {
+			if (escaped) {
+				escaped = false;
+			} else if (*p == '\\') {
+				escaped = true;
+			} else if (*p == '"') {
+				in_string = false;
+			}
+			continue;
+		}
+
+		if (*p == '"') {
+			in_string = true;
+		} else if (*p == '{') {
+			depth++;
+		} else if (*p == '}') {
+			depth--;
+			if (depth == 0)
+				return p;
+		}
+	}
+
+	return NULL;
+}
+
+static bool parse_json_string_value(const char *value, char *dest, size_t dest_size) {
+	size_t i = 0;
+	const char *p = skip_ws(value);
+
+	if (!p || *p != '"' || dest_size == 0)
+		return false;
+
+	++p;
+	while (*p != '\0' && *p != '"' && i + 1 < dest_size) {
+		if (*p == '\\') {
+			++p;
+			if (*p == '\0')
+				break;
+			switch (*p) {
+			case 'n':
+				dest[i++] = '\n';
+				break;
+			case 'r':
+				dest[i++] = '\r';
+				break;
+			case 't':
+				dest[i++] = '\t';
+				break;
+			case '\\':
+			case '"':
+			case '/':
+				dest[i++] = *p;
+				break;
+			default:
+				dest[i++] = *p;
+				break;
+			}
+			++p;
+			continue;
+		}
+		dest[i++] = *p++;
+	}
+
+	dest[i] = '\0';
+	return true;
+}
+
+static bool extract_json_string(const char *obj, const char *key, char *dest,
+								size_t dest_size) {
+	const char *p = strstr(obj, key);
+	if (!p)
+		return false;
+	p = strchr(p, ':');
+	if (!p)
+		return false;
+	return parse_json_string_value(p + 1, dest, dest_size);
+}
+
+static bool extract_json_int(const char *obj, const char *key, int32_t *out) {
+	char *end = NULL;
+	const char *p = strstr(obj, key);
+	long value;
+
+	if (!p)
+		return false;
+	p = strchr(p, ':');
+	if (!p)
+		return false;
+	p = skip_ws(p + 1);
+	if (!p)
+		return false;
+
+	value = strtol(p, &end, 10);
+	if (end == p)
+		return false;
+
+	*out = (int32_t)value;
+	return true;
+}
+
+static bool extract_json_object_range(const char *obj, const char *key,
+									  const char **start, const char **end) {
+	const char *p = strstr(obj, key);
+	if (!p)
+		return false;
+	p = strchr(p, ':');
+	if (!p)
+		return false;
+	p = skip_ws(p + 1);
+	if (!p || *p != '{')
+		return false;
+	*start = p;
+	*end = find_matching_brace(p);
+	return *end != NULL;
+}
+
+static bool parse_geom_object(const char *obj, const char *key, SessionRect *geom) {
+	const char *start = NULL, *end = NULL;
+	char *sub = NULL;
+	bool ok;
+	size_t len;
+
+	if (!extract_json_object_range(obj, key, &start, &end))
+		return false;
+
+	len = (size_t)(end - start + 1);
+	sub = ecalloc(len + 1, 1);
+	memcpy(sub, start, len);
+
+	ok = extract_json_int(sub, "\"x\"", &geom->x) &&
+		 extract_json_int(sub, "\"y\"", &geom->y) &&
+		 extract_json_int(sub, "\"width\"", &geom->width) &&
+		 extract_json_int(sub, "\"height\"", &geom->height);
+
+	free(sub);
+	return ok;
+}
+
+static bool parse_session_entry(const char *obj, SessionRestoreEntry *entry) {
+	int32_t tags = 0;
+
+	memset(entry, 0, sizeof(*entry));
+
+	if (!extract_json_string(obj, "\"app_id\"", entry->app_id,
+							 sizeof(entry->app_id)))
+		return false;
+
+	extract_json_string(obj, "\"title\"", entry->title, sizeof(entry->title));
+	extract_json_string(obj, "\"monitor\"", entry->monitor,
+						sizeof(entry->monitor));
+	extract_json_string(obj, "\"launch_command\"", entry->launch_command,
+						sizeof(entry->launch_command));
+	extract_json_int(obj, "\"pid\"", &entry->pid);
+	extract_json_int(obj, "\"tags\"", &tags);
+	entry->tags = (uint32_t)tags;
+	extract_json_int(obj, "\"is_floating\"", &entry->is_floating);
+	extract_json_int(obj, "\"is_fullscreen\"", &entry->is_fullscreen);
+	extract_json_int(obj, "\"is_minimized\"", &entry->is_minimized);
+	parse_geom_object(obj, "\"geom\"", &entry->geom);
+	parse_geom_object(obj, "\"float_geom\"", &entry->float_geom);
+
+	return true;
+}
+
+static bool load_pending_entries(void) {
+	char *path = session_file_path();
+	char *contents = NULL;
+	FILE *in = NULL;
+	const char *cursor;
+	bool loaded = false;
+
+	free_pending_entries();
+	if (!path)
+		return false;
+
+	in = fopen(path, "r");
+	if (!in)
+		goto cleanup;
+
+	if (fseek(in, 0, SEEK_END) != 0)
+		goto cleanup;
+	long size = ftell(in);
+	if (size < 0 || fseek(in, 0, SEEK_SET) != 0)
+		goto cleanup;
+
+	contents = ecalloc((size_t)size + 1, 1);
+	if (fread(contents, 1, (size_t)size, in) != (size_t)size)
+		goto cleanup;
+	contents[size] = '\0';
+
+	cursor = contents;
+	while ((cursor = strchr(cursor, '{')) != NULL) {
+		const char *end = find_matching_brace(cursor);
+		SessionRestoreEntry entry;
+		char *obj;
+		size_t len;
+
+		if (!end)
+			break;
+
+		len = (size_t)(end - cursor + 1);
+		obj = ecalloc(len + 1, 1);
+		memcpy(obj, cursor, len);
+
+		if (parse_session_entry(obj, &entry)) {
+				PendingSessionEntry *new_entries = realloc(
+					pending_entries, sizeof(*pending_entries) * (pending_count + 1));
+				if (!new_entries) {
+					free(obj);
+					goto cleanup;
+				}
+				pending_entries = new_entries;
+				pending_entries[pending_count].entry = entry;
+				pending_entries[pending_count].used = false;
+				pending_count++;
+			loaded = true;
+		}
+
+		free(obj);
+		cursor = end + 1;
+	}
+
+cleanup:
+	if (in)
+		fclose(in);
+	free(contents);
+	free(path);
+	return loaded;
+}
+
+static PendingSessionEntry *find_pending_match(const char *appid, const char *title,
+											   const char *monitor) {
+	PendingSessionEntry *fallback = NULL;
+	PendingSessionEntry *monitor_match = NULL;
+
+	for (size_t i = 0; i < pending_count; ++i) {
+		PendingSessionEntry *candidate = &pending_entries[i];
+		if (candidate->used)
+			continue;
+		if (strcmp(candidate->entry.app_id, appid) != 0)
+			continue;
+
+		if (title && title[0] != '\0' &&
+			strcmp(candidate->entry.title, title) == 0) {
+			if (monitor && monitor[0] != '\0' &&
+				strcmp(candidate->entry.monitor, monitor) == 0)
+				return candidate;
+			if (!fallback)
+				fallback = candidate;
+		}
+
+		if (!monitor_match && monitor && monitor[0] != '\0' &&
+			strcmp(candidate->entry.monitor, monitor) == 0) {
+			monitor_match = candidate;
+		}
+
+		if (!fallback)
+			fallback = candidate;
+	}
+
+	return monitor_match ? monitor_match : fallback;
+}
+
+static bool session_resolve_launch_command(SessionRestoreEntry *entry) {
+	const char *mapped_command;
+
+	if (!entry || entry->app_id[0] == '\0')
+		return false;
+
+	/* Explicit user mapping wins over best-effort persisted launch data. */
+	mapped_command = mango_session_lookup_launch_command(entry->app_id,
+														 entry->title);
+	if (mapped_command && mapped_command[0] != '\0') {
+		strncpy(entry->launch_command, mapped_command,
+				sizeof(entry->launch_command) - 1);
+		entry->launch_command[sizeof(entry->launch_command) - 1] = '\0';
+		return true;
+	}
+
+	return entry->launch_command[0] != '\0';
+}
+
+static void session_spawn_restore_entries(void) {
+	for (size_t i = 0; i < pending_count; ++i) {
+		SessionRestoreEntry *entry = &pending_entries[i].entry;
+
+		if (!session_resolve_launch_command(entry))
+			continue;
+
+		mango_session_spawn_command(entry->launch_command);
+	}
+}
+
+void session_init(void) {}
+
+void session_shutdown(void) {
+	free_pending_entries();
+	restore_started = false;
+}
+
+void session_maybe_restore_startup(void) {
+	if (!session_is_enabled() || restore_started)
+		return;
+
+	restore_started = true;
+	if (!load_pending_entries())
+		return;
+
+	session_spawn_restore_entries();
+}
+
+void session_handle_client_mapped(Client *c) {
+	PendingSessionEntry *match;
+	const char *appid;
+	const char *title;
+	const char *monitor;
+
+	if (!restore_started || pending_count == 0 || !c)
+		return;
+
+	appid = mango_session_client_appid(c);
+	if (!appid || appid[0] == '\0' || strcmp(appid, "broken") == 0)
+		return;
+
+	title = mango_session_client_title(c);
+	monitor = mango_session_client_monitor(c);
+	match = find_pending_match(appid, title, monitor);
+	if (!match)
+		return;
+
+	mango_session_remember_client_launch_command(c, match->entry.launch_command);
+	mango_session_apply_restore_entry(c, &match->entry);
+	match->used = true;
+}
+
+void session_handle_client_destroyed(Client *c) {
+	(void)c;
+}
+
+void session_save_now(bool is_final_shutdown) {
+	FILE *out = NULL;
+	char *dir = NULL, *tmp_path = NULL, *final_path = NULL;
+	int32_t count = 0;
+
+	if (!session_is_enabled())
+		return;
+
+	dir = session_data_dir();
+	if (!dir || !mkdir_p(dir))
+		goto cleanup;
+
+	tmp_path = string_printf("%s/session.json.tmp", dir);
+	final_path = string_printf("%s/session.json", dir);
+	if (!tmp_path || !final_path)
+		goto cleanup;
+
+	out = fopen(tmp_path, "w");
+	if (!out)
+		goto cleanup;
+
+	count = mango_session_write_snapshot(out);
+	if (fclose(out) != 0) {
+		out = NULL;
+		goto cleanup;
+	}
+	out = NULL;
+
+	if (count <= 0 && is_final_shutdown) {
+		unlink(tmp_path);
+		goto cleanup;
+	}
+
+	if (rename(tmp_path, final_path) != 0)
+		unlink(tmp_path);
+
+cleanup:
+	if (out)
+		fclose(out);
+	free(dir);
+	free(tmp_path);
+	free(final_path);
+}
+
+bool session_is_enabled(void) { return mango_session_is_config_enabled() != 0; }
+
+bool session_is_restorable_client(Client *c) {
+	(void)c;
+	return false;
+}

src/session/session.h

@@ -0,0 +1,39 @@
+#ifndef SESSION_H
+#define SESSION_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct Client Client;
+
+typedef struct {
+	int32_t x;
+	int32_t y;
+	int32_t width;
+	int32_t height;
+} SessionRect;
+
+typedef struct {
+	char app_id[256];
+	char title[512];
+	char monitor[128];
+	char launch_command[1024];
+	int32_t pid;
+	uint32_t tags;
+	int32_t is_floating;
+	int32_t is_fullscreen;
+	int32_t is_minimized;
+	SessionRect geom;
+	SessionRect float_geom;
+} SessionRestoreEntry;
+
+void session_init(void);
+void session_shutdown(void);
+void session_maybe_restore_startup(void);
+void session_handle_client_mapped(Client *c);
+void session_handle_client_destroyed(Client *c);
+void session_save_now(bool is_final_shutdown);
+bool session_is_enabled(void);
+bool session_is_restorable_client(Client *c);
+
+#endif