swaybar: Replace fgets with read and own buffer

1 files changed, 167 insertions, 54 deletions

diff --git a/swaybar/main.c b/swaybar/main.c
index 110904ba..86ccfbb9 100644
--- a/swaybar/main.c
+++ b/swaybar/main.c
@@ -1,3 +1,4 @@
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -60,9 +61,9 @@ list_t *status_line = NULL;
 list_t *workspaces = NULL;
 int socketfd;
 pid_t pid;
-int pipefd[2];
-FILE *command;
+int status_read_fd;
 char line[1024];
+char line_rest[1024];
 char *output, *status_command;
 struct registry *registry;
 struct window *window;
@@ -110,10 +111,11 @@ struct {
         int bufsize;
         char *buffer;
         char *line_start;
+        char *parserpos;
         bool escape;
         int depth;
         int state[I3JSON_MAXDEPTH+1];
-} i3json_state = { 0, NULL, NULL, false, 0, { I3JSON_UNKNOWN } };
+} i3json_state = { 0, NULL, NULL, NULL, false, 0, { I3JSON_UNKNOWN } };
 
 
 void swaybar_teardown() {
@@ -122,8 +124,8 @@ void swaybar_teardown() {
                 registry_teardown(registry);
         }
 
-        if (command) {
-                fclose(command);
+        if (status_read_fd) {
+                close(status_read_fd);
         }
 
         if (pid) {
@@ -137,8 +139,8 @@ void swaybar_teardown() {
                 }
         }
 
-        if (pipefd[0]) {
-                close(pipefd[0]);
+        if (status_read_fd) {
+                close(status_read_fd);
         }
 }
 
@@ -607,34 +609,124 @@ void parse_json(const char *text) {
         json_object_put(results);
 }
 
-int i3json_handle(FILE *file) {
-        char *c;
-        int handled = 0;
-        // handle partially buffered data
-        // make sure 1023+1 bytes at the end are free
-        if (i3json_state.line_start) {
-                int len = strlen(i3json_state.line_start);
-                memmove(i3json_state.buffer, i3json_state.line_start, len+1);
-                if (i3json_state.bufsize < len+1024) {
-                        i3json_state.bufsize += 1024;
-                        i3json_state.buffer = realloc(i3json_state.buffer, i3json_state.bufsize);
+// Read line from file descriptor, only show the line tail if it is too long.
+// In non-blocking mode treat "no more data" as a linebreak.
+// If data after a line break has been read, return it in rest.
+// If rest is non-empty, then use that as the start of the next line.
+int read_line_tail(int fd, char *buf, int nbyte, char *rest) {
+        if (fd < 0 || !buf || !nbyte) {
+                return -1;
+        }
+        int l;
+        char *buffer = malloc(nbyte*2+1);
+        char *readpos = buffer;
+        char *lf;
+        // prepend old data to new line if necessary
+        if (rest) {
+                l = strlen(rest);
+                if (l > nbyte) {
+                        strcpy(buffer, rest + l - nbyte);
+                        readpos += nbyte;
+                } else if (l) {
+                        strcpy(buffer, rest);
+                        readpos += l;
+                }
+        }
+        // read until a linefeed is found or no more data is available
+        while ((l = read(fd, readpos, nbyte)) > 0) {
+                readpos[l] = '\0';
+                lf = strchr(readpos, '\n');
+                if (lf) {
+                        // linefeed found, replace with \0
+                        *lf = '\0';
+                        // give data from the end of the line, try to fill the buffer
+                        if (lf-buffer > nbyte) {
+                                strcpy(buf, lf - nbyte + 1);
+                        } else {
+                                strcpy(buf, buffer);
+                        }
+                        // we may have read data from the next line, save it to rest
+                        if (rest) {
+                                rest[0] = '\0';
+                                strcpy(rest, lf + 1);
+                        }
+                        free(buffer);
+                        return strlen(buf);
+                } else {
+                        // no linefeed found, slide data back.
+                        int overflow = readpos - buffer + l - nbyte;
+                        if (overflow > 0) {
+                                memmove(buffer, buffer + overflow , nbyte + 1);
+                        }
                 }
-                c = i3json_state.buffer+len;
-                i3json_state.line_start = i3json_state.buffer;
-        } else if (!i3json_state.buffer) {
-                i3json_state.buffer = malloc(1024);
-                i3json_state.bufsize = 1024;
-                c = i3json_state.buffer;
+        }
+        if (l < 0) {
+                free(buffer);
+                return l;
+        }
+        readpos[l]='\0';
+        if (rest) {
+                rest[0] = '\0';
+        }
+        if (nbyte < readpos - buffer + l - 1) {
+                memcpy(buf, readpos - nbyte + l + 1, nbyte);
         } else {
-                c = i3json_state.buffer;
+                strncpy(buf, buffer, nbyte);
+        }
+        buf[nbyte-1] = '\0';
+        free(buffer);
+        return strlen(buf);
+}
+
+// make sure that enough buffer space is available starting from parserpos
+void i3json_ensure_free(int min_free) {
+        int _step = 10240;
+        int r = min_free % _step;
+        if (r) {
+                min_free += _step - r;
+        }
+        if (!i3json_state.buffer) {
+                i3json_state.buffer = malloc(min_free);
+                i3json_state.bufsize = min_free;
+                i3json_state.parserpos = i3json_state.buffer;
+        } else {
+                int len = 0;
+                int pos = 0;
+                if (i3json_state.line_start) {
+                        len = strlen(i3json_state.line_start);
+                        pos = i3json_state.parserpos - i3json_state.line_start;
+                        if (i3json_state.line_start != i3json_state.buffer) {
+                                memmove(i3json_state.buffer, i3json_state.line_start, len+1);
+                        }
+                } else {
+                        len = strlen(i3json_state.buffer);
+                }
+                if (i3json_state.bufsize < len+min_free) {
+                        i3json_state.bufsize += min_free;
+                        if (i3json_state.bufsize > 1024000) {
+                                sway_abort("Status line json too long or malformed.");
+                        }
+                        i3json_state.buffer = realloc(i3json_state.buffer, i3json_state.bufsize);
+                        if (!i3json_state.buffer) {
+                                sway_abort("Could not allocate json buffer");
+                        }
+                }
+                if (i3json_state.line_start) {
+                        i3json_state.line_start = i3json_state.buffer;
+                        i3json_state.parserpos = i3json_state.buffer + pos;
+                } else {
+                        i3json_state.parserpos = i3json_state.buffer;
+                }
         }
         if (!i3json_state.buffer) {
                 sway_abort("Could not allocate buffer.");
         }
-        // get fresh data at the end of the buffer
-        if (!fgets(c, 1023, file)) return -1;
-        c[1023] = '\0';
+}
 
+// continue parsing from last parserpos
+int i3json_parse() {
+        char *c = i3json_state.parserpos;
+        int handled = 0;
         while (*c) {
                 if (i3json_state.state[i3json_state.depth] == I3JSON_STRING) {
                         if (!i3json_state.escape && *c == '"') {
@@ -679,9 +771,30 @@ int i3json_handle(FILE *file) {
                 }
                 ++c;
         }
+        i3json_state.parserpos = c;
         return handled;
 }
 
+// append data and parse it.
+int i3json_handle_data(char *data) {
+        int len = strlen(data);
+        i3json_ensure_free(len);
+        strcpy(i3json_state.parserpos, data);
+        return i3json_parse();
+}
+
+// read data from fd and parse it.
+int i3json_handle_fd(int fd) {
+        i3json_ensure_free(10240);
+        // get fresh data at the end of the buffer
+        int readlen = read(fd, i3json_state.parserpos, 10239);
+        if (readlen < 0) {
+                return readlen;
+        }
+        i3json_state.parserpos[readlen] = '\0';
+        return i3json_parse();
+}
+
 void poll_for_update() {
         fd_set readfds;
         int activity;
@@ -698,7 +811,7 @@ void poll_for_update() {
                 dirty = false;
                 FD_ZERO(&readfds);
                 FD_SET(socketfd, &readfds);
-                FD_SET(pipefd[0], &readfds);
+                FD_SET(status_read_fd, &readfds);
 
                 activity = select(FD_SETSIZE, &readfds, NULL, NULL, NULL);
                 if (activity < 0) {
@@ -714,41 +827,40 @@ void poll_for_update() {
                         dirty = true;
                 }
 
-                if (status_command && FD_ISSET(pipefd[0], &readfds)) {
+                if (status_command && FD_ISSET(status_read_fd, &readfds)) {
                         sway_log(L_DEBUG, "Got update from status command.");
-                        int linelen;
                         switch (protocol) {
                         case I3BAR:
                                 sway_log(L_DEBUG, "Got i3bar protocol.");
-                                if (i3json_handle(command) > 0) {
+                                if (i3json_handle_fd(status_read_fd) > 0) {
                                         dirty = true;
                                 }
                                 break;
                         case TEXT:
-                        case UNDEF:
                                 sway_log(L_DEBUG, "Got text protocol.");
-                                fgets(line, sizeof(line), command);
-                                linelen = strlen(line) - 1;
-                                if (line[linelen] == '\n') {
-                                        line[linelen] = '\0';
+                                read_line_tail(status_read_fd, line, sizeof(line), line_rest);
+                                dirty = true;
+                                break;
+                        case UNDEF:
+                                sway_log(L_DEBUG, "Detecting protocol...");
+                                if (read_line_tail(status_read_fd, line, sizeof(line), line_rest) < 0) {
+                                        break;
                                 }
                                 dirty = true;
-                                if (protocol == UNDEF) {
-                                        protocol = TEXT;
-                                        if (line[0] == '{') {
-                                                // detect i3bar json protocol
-                                                json_object *proto = json_tokener_parse(line);
-                                                json_object *version;
-                                                if (proto) {
-                                                        if (json_object_object_get_ex(proto, "version", &version)
-                                                                                && json_object_get_int(version) == 1
-                                                        ) {
-                                                                sway_log(L_DEBUG, "Switched to i3bar protocol.");
-                                                                protocol = I3BAR;
-                                                                line[0] = '\0';
-                                                        }
-                                                        json_object_put(proto);
+                                protocol = TEXT;
+                                if (line[0] == '{') {
+                                        // detect i3bar json protocol
+                                        json_object *proto = json_tokener_parse(line);
+                                        json_object *version;
+                                        if (proto) {
+                                                if (json_object_object_get_ex(proto, "version", &version)
+                                                                        && json_object_get_int(version) == 1
+                                                ) {
+                                                        sway_log(L_DEBUG, "Switched to i3bar protocol.");
+                                                        protocol = I3BAR;
+                                                        i3json_handle_data(line_rest);
                                                 }
+                                                json_object_put(proto);
                                         }
                                 }
                                 break;
@@ -831,6 +943,7 @@ int main(int argc, char **argv) {
         bar_ipc_init(desired_output, bar_id);
 
         if (status_command) {
+                int pipefd[2];
                 pipe(pipefd);
                 pid = fork();
                 if (pid == 0) {
@@ -848,8 +961,8 @@ int main(int argc, char **argv) {
                 }
 
                 close(pipefd[1]);
-                command = fdopen(pipefd[0], "r");
-                setbuf(command, NULL);
+                status_read_fd = pipefd[0];
+                fcntl(status_read_fd, F_SETFL, O_NONBLOCK);
                 line[0] = '\0';
         }