Demarcate i3bar JSON into individual updates

include/swaybar/status_line.h

@@ -7,10 +7,52 @@
 
 enum status_protocol {
 	PROTOCOL_UNDEF,
+	PROTOCOL_ERROR,
 	PROTOCOL_TEXT,
 	PROTOCOL_I3BAR,
 };
 
+struct text_protocol_state {
+	char *buffer;
+	size_t buffer_size;
+};
+
+enum json_node_type {
+	JSON_NODE_UNKNOWN,
+	JSON_NODE_ARRAY,
+	JSON_NODE_STRING,
+};
+
+struct i3bar_protocol_state {
+	bool click_events;
+	char *buffer;
+	size_t buffer_size;
+	size_t buffer_index;
+	const char *current_node;
+	bool escape;
+	size_t depth;
+	enum json_node_type nodes[16];
+};
+
+struct i3bar_block {
+	struct wl_list link;
+	char *full_text, *short_text, *align;
+	bool urgent;
+	uint32_t color;
+	int min_width;
+	char *name, *instance;
+	bool separator;
+	int separator_block_width;
+	bool markup;
+	// Airblader features
+	uint32_t background;
+	uint32_t border;
+	int border_top;
+	int border_bottom;
+	int border_left;
+	int border_right;
+};
+
 struct status_line {
 	pid_t pid;
 	int read_fd, write_fd;
@@ -18,13 +60,16 @@ struct status_line {
 
 	enum status_protocol protocol;
 	const char *text;
+	struct wl_list blocks; // i3bar_block::link
 
-	char *buffer;
-	size_t buffer_size;
+	struct text_protocol_state text_state;
+	struct i3bar_protocol_state i3bar_state;
 };
 
 struct status_line *status_line_init(char *cmd);
 void status_line_free(struct status_line *status);
 bool handle_status_readable(struct status_line *status);
+int i3bar_readable(struct status_line *status);
+void status_error(struct status_line *status, const char *text);
 
 #endif

swaybar/i3bar.c

@@ -0,0 +1,88 @@
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wlr/util/log.h>
+#include "swaybar/config.h"
+#include "swaybar/status_line.h"
+
+static void i3bar_parse_json(struct status_line *status, const char *text) {
+	wlr_log(L_DEBUG, "got json: %s", text);
+}
+
+int i3bar_readable(struct status_line *status) {
+	struct i3bar_protocol_state *state = &status->i3bar_state;
+
+	char *cur = &state->buffer[state->buffer_index];
+	ssize_t n = read(status->read_fd, cur,
+			state->buffer_size - state->buffer_index);
+	if (n == 0) {
+		return 0;
+	}
+
+	if (n == (ssize_t)(state->buffer_size - state->buffer_index)) {
+		state->buffer_size = state->buffer_size * 2;
+		char *new_buffer = realloc(state->buffer, state->buffer_size);
+		if (!new_buffer) {
+			free(state->buffer);
+			status_error(status, "[failed to allocate buffer]");
+			return -1;
+		}
+		state->buffer = new_buffer;
+	}
+
+	int handled = 0;
+	while (*cur) {
+		if (state->nodes[state->depth] == JSON_NODE_STRING) {
+			if (!state->escape && *cur == '"') {
+				--state->depth;
+			}
+			state->escape = !state->escape && *cur == '\\';
+		} else {
+			switch (*cur) {
+			case '[':
+				++state->depth;
+				if (state->depth >
+						sizeof(state->nodes) / sizeof(state->nodes[0])) {
+					status_error(status, "[i3bar json too deep]");
+					return -1;
+				}
+				state->nodes[state->depth] = JSON_NODE_ARRAY;
+				if (state->depth == 1) {
+					state->current_node = cur;
+				}
+				break;
+			case ']':
+				if (state->nodes[state->depth] != JSON_NODE_ARRAY) {
+					status_error(status, "[failed to parse i3bar json]");
+					return -1;
+				}
+				--state->depth;
+				if (state->depth == 0) {
+					// cur[1] is valid since cur[0] != '\0'
+					char p = cur[1];
+					cur[1] = '\0';
+					i3bar_parse_json(status, state->current_node);
+					cur[1] = p;
+					memmove(state->buffer, cur,
+							state->buffer_size - (cur - state->buffer));
+					++handled;
+					cur = state->buffer;
+					state->current_node = cur + 1;
+				}
+				break;
+			case '"':
+				++state->depth;
+				if (state->depth >
+						sizeof(state->nodes) / sizeof(state->nodes[0])) {
+					status_error(status, "[i3bar json too deep]");
+					return -1;
+				}
+				state->nodes[state->depth] = JSON_NODE_STRING;
+				break;
+			}
+		}
+		++cur;
+	}
+	state->buffer_index = cur - state->buffer;
+	return handled;
+}

swaybar/meson.build

@@ -3,6 +3,7 @@ executable(
 		'bar.c',
 		'config.c',
 		'event_loop.c',
+		'i3bar.c',
 		'ipc.c',
 		'main.c',
 		'render.c',

swaybar/status_line.c

@@ -1,5 +1,6 @@
 #define _POSIX_C_SOURCE
 #include <fcntl.h>
+#include <json-c/json.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -9,35 +10,78 @@
 #include "swaybar/status_line.h"
 #include "readline.h"
 
+void status_error(struct status_line *status, const char *text) {
+	close(status->read_fd);
+	close(status->write_fd);
+	status->protocol = PROTOCOL_ERROR;
+	status->text = text;
+}
+
 bool handle_status_readable(struct status_line *status) {
-	char *line = read_line_buffer(status->read,
-			status->buffer, status->buffer_size);
+	char *line;
 	switch (status->protocol) {
+	case PROTOCOL_ERROR:
+		return false;
 	case PROTOCOL_I3BAR:
-		// TODO
+		if (i3bar_readable(status) > 0) {
+			return true;
+		}
 		break;
 	case PROTOCOL_TEXT:
-		status->text = line;
+		line = read_line_buffer(status->read,
+				status->text_state.buffer, status->text_state.buffer_size);
+		if (!line) {
+			status_error(status, "[error reading from status command]");
+		} else {
+			status->text = line;
+		}
 		return true;
 	case PROTOCOL_UNDEF:
+		line = read_line_buffer(status->read,
+				status->text_state.buffer, status->text_state.buffer_size);
 		if (!line) {
+			status_error(status, "[error reading from status command]");
 			return false;
 		}
 		if (line[0] == '{') {
-			// TODO: JSON
+			json_object *proto = json_tokener_parse(line);
+			if (proto) {
+				json_object *version;
+				if (json_object_object_get_ex(proto, "version", &version)
+							&& json_object_get_int(version) == 1) {
+					wlr_log(L_DEBUG, "Switched to i3bar protocol.");
+					status->protocol = PROTOCOL_I3BAR;
+				}
+				json_object *click_events;
+				if (json_object_object_get_ex(
+							proto, "click_events", &click_events)
+						&& json_object_get_boolean(click_events)) {
+					wlr_log(L_DEBUG, "Enabled click events.");
+					status->i3bar_state.click_events = true;
+					const char *events_array = "[\n";
+					write(status->write_fd, events_array, strlen(events_array));
+				}
+				json_object_put(proto);
+			}
+
+			status->protocol = PROTOCOL_I3BAR;
+			free(status->text_state.buffer);
+			status->i3bar_state.buffer_size = 4096;
+			status->i3bar_state.buffer =
+				malloc(status->i3bar_state.buffer_size);
 		} else {
-			status->text = line;
 			status->protocol = PROTOCOL_TEXT;
+			status->text = line;
 		}
-		return false;
+		return true;
 	}
 	return false;
 }
 
 struct status_line *status_line_init(char *cmd) {
 	struct status_line *status = calloc(1, sizeof(struct status_line));
-	status->buffer_size = 4096;
-	status->buffer = malloc(status->buffer_size);
+	status->text_state.buffer_size = 8192;
+	status->text_state.buffer = malloc(status->text_state.buffer_size);
 
 	int pipe_read_fd[2];
 	int pipe_write_fd[2];