Reorganize code and remove hack for empty block outputs

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Utkarsh Verma 2023-03-25 21:38:05 +05:30
parent f6a5fa6480
commit 8dd9bc6a7d
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17 changed files with 531 additions and 362 deletions

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BasedOnStyle: Google BasedOnStyle: Google
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.clangd Normal file
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CompileFlags:
Add:
- "-I."
- "-I./inc"
- "-I.."
- "-I../inc"

3
.gitignore vendored
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*.o build/
.cache/
dwmblocks dwmblocks

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.POSIX: .POSIX:
PREFIX = /usr/local BUILD_DIR := build
CFLAGS = -Ofast SRC_DIR := src
LDLIBS = -lX11 INC_DIR := inc
BIN = dwmblocks PREFIX := /usr/local
CFLAGS := -Wall -Ofast -I. -I$(INC_DIR)
LDLIBS := -lX11
$(BIN): main.o BIN := dwmblocks
$(CC) $^ -o $@ $(LDLIBS) VPATH := $(SRC_DIR)
OBJS := $(subst $(SRC_DIR)/,$(BUILD_DIR)/,$(subst .c,.o,$(wildcard $(SRC_DIR)/*.c)))
OBJS += $(addprefix $(BUILD_DIR)/,$(subst .c,.o,$(wildcard *.c)))
all: $(BUILD_DIR)/$(BIN)
$(BUILD_DIR)/$(BIN): $(OBJS)
$(LINK.o) $^ $(LDLIBS) -o $@
$(BUILD_DIR)/%.o: %.c config.h | $(BUILD_DIR)
$(COMPILE.c) -o $@ $<
$(BUILD_DIR):
mkdir -p $(BUILD_DIR)
clean: clean:
$(RM) *.o $(BIN) $(RM) -r $(BUILD_DIR)
install: $(BIN) install: $(BUILD_DIR)/$(BIN)
install -D -m 755 $(BIN) $(DESTDIR)$(PREFIX)/bin/$(BIN) install -D -m 755 $< $(DESTDIR)/$(PREFIX)/bin/$(BIN)
uninstall: uninstall:
$(RM) $(DESTDIR)$(PREFIX)/bin/$(BIN) $(RM) $(DESTDIR)/$(PREFIX)/bin/$(BIN)
.PHONY: clean install uninstall .PHONY: all clean install uninstall

104
README.md
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# dwmblocks-async # dwmblocks-async
A [`dwm`](https://dwm.suckless.org) status bar that has a modular, async design, so it is always responsive. Imagine `i3blocks`, but for `dwm`.
A [`dwm`](https://dwm.suckless.org) status bar that has a modular, async
design, so it is always responsive. Imagine `i3blocks`, but for `dwm`.
![A lean config of dwmblocks-async.](preview.png) ![A lean config of dwmblocks-async.](preview.png)
## Features ## Features
- [Modular](#modifying-the-blocks) - [Modular](#modifying-the-blocks)
- Lightweight - Lightweight
- [Suckless](https://suckless.org/philosophy) - [Suckless](https://suckless.org/philosophy)
- Blocks: - Blocks:
- [Clickable](#clickable-blocks) - [Clickable](#clickable-blocks)
- Loaded asynchronously - Loaded asynchronously
- [Updates can be externally triggered](#signalling-changes) - [Updates can be externally triggered](#signalling-changes)
- Compatible with `i3blocks` scripts - Compatible with `i3blocks` scripts
> Additionally, this build of `dwmblocks` is more optimized and fixes the flickering of the status bar when scrolling. > Additionally, this build of `dwmblocks` is more optimized and fixes the
> flickering of the status bar when scrolling.
## Why `dwmblocks`? ## Why `dwmblocks`?
In `dwm`, you have to set the status bar through an infinite loop, like so: In `dwm`, you have to set the status bar through an infinite loop, like so:
```sh ```sh
@ -25,7 +30,9 @@ while :; do
done done
``` ```
This is inefficient when running multiple commands that need to be updated at different frequencies. For example, to display an unread mail count and a clock in the status bar: This is inefficient when running multiple commands that need to be updated at
different frequencies. For example, to display an unread mail count and a clock
in the status bar:
```sh ```sh
while :; do while :; do
@ -34,17 +41,30 @@ while :; do
done done
``` ```
Both are executed at the same rate, which is wasteful. Ideally, the mail counter would be updated every thirty minutes, since there's a limit to the number of requests I can make using Gmail's APIs (as a free user). Both are executed at the same rate, which is wasteful. Ideally, the mail
counter would be updated every thirty minutes, since there's a limit to the
number of requests I can make using Gmail's APIs (as a free user).
`dwmblocks` allows you to divide the status bar into multiple blocks, each of which can be updated at its own interval. This effectively addresses the previous issue, because the commands in a block are only executed once within that time frame. `dwmblocks` allows you to divide the status bar into multiple blocks, each of
which can be updated at its own interval. This effectively addresses the
previous issue, because the commands in a block are only executed once within
that time frame.
## Why `dwmblocks-async`? ## Why `dwmblocks-async`?
The magic of `dwmblocks-async` is in the `async` part. Since vanilla `dwmblocks` executes the commands of each block sequentially, it leads to annoying freezes. In cases where one block takes several seconds to execute, like in the mail and date blocks example from above, the delay is clearly visible. Fire up a new instance of `dwmblocks` and you'll see!
With `dwmblocks-async`, the computer executes each block asynchronously (simultaneously). The magic of `dwmblocks-async` is in the `async` part. Since vanilla
`dwmblocks` executes the commands of each block sequentially, it leads to
annoying freezes. In cases where one block takes several seconds to execute,
like in the mail and date blocks example from above, the delay is clearly
visible. Fire up a new instance of `dwmblocks` and you'll see!
With `dwmblocks-async`, the computer executes each block asynchronously
(simultaneously).
## Installation ## Installation
Clone this repository, modify `config.h` appropriately, then compile the program:
Clone this repository, modify `config.h` appropriately, then compile the
program:
```sh ```sh
git clone https://github.com/UtkarshVerma/dwmblocks-async.git git clone https://github.com/UtkarshVerma/dwmblocks-async.git
@ -54,7 +74,9 @@ sudo make install
``` ```
## Usage ## Usage
To set `dwmblocks-async` as your status bar, you need to run it as a background process on startup. One way is to add the following to `~/.xinitrc`:
To set `dwmblocks-async` as your status bar, you need to run it as a background
process on startup. One way is to add the following to `~/.xinitrc`:
```sh ```sh
# The binary of `dwmblocks-async` is named `dwmblocks` # The binary of `dwmblocks-async` is named `dwmblocks`
@ -62,26 +84,27 @@ dwmblocks &
``` ```
### Modifying the blocks ### Modifying the blocks
You can define your status bar blocks in `config.h`:
You can define your status bar blocks in `config.c`:
```c ```c
const Block blocks[] = { Block blocks[] = {
... ...
BLOCK("volume", 0, 5), {"volume", 0, 5},
BLOCK("date", 1800, 1), {"date", 1800, 1},
... ...
} }
``` ```
Each block has the following properties: Each block has the following properties:
Property|Description | Property | Description |
-|- | --------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
Command | The command you wish to execute in your block. | Command | The command you wish to execute in your block. |
Update interval | Time in seconds, after which you want the block to update. If `0`, the block will never be updated. | Update interval | Time in seconds, after which you want the block to update. If `0`, the block will never be updated. |
Update signal | Signal to be used for triggering the block. Must be a positive integer. If `0`, a signal won't be set up for the block and it will be unclickable. | Update signal | Signal to be used for triggering the block. Must be a positive integer. If `0`, a signal won't be set up for the block and it will be unclickable. |
Additional parameters can be modified: Apart from defining the blocks, features can be toggled through `config.h`:
```c ```c
// Maximum possible length of output from block, expressed in number of characters. // Maximum possible length of output from block, expressed in number of characters.
@ -91,31 +114,48 @@ Additional parameters can be modified:
#define DELIMITER " " #define DELIMITER " "
// Adds a leading delimiter to the status bar, useful for powerline. // Adds a leading delimiter to the status bar, useful for powerline.
#define LEADING_DELIMITER #define LEADING_DELIMITER 1
// Enable clickability for blocks. See the "Clickable blocks" section below. // Enable clickability for blocks. See the "Clickable blocks" section below.
#define CLICKABLE_BLOCKS #define CLICKABLE_BLOCKS 1
``` ```
### Signalling changes ### Signalling changes
Most status bars constantly rerun all scripts every few seconds. This is an option here, but a superior choice is to give your block a signal through which you can indicate it to update on relevant event, rather than have it rerun idly.
For example, the volume block has the update signal `5` by default. I run `kill -39 $(pidof dwmblocks)` alongside my volume shortcuts in `dwm` to only update it when relevant. Just add `34` to your signal number! You could also run `pkill -RTMIN+5 dwmblocks`, but it's slower. Most status bars constantly rerun all scripts every few seconds. This is an
option here, but a superior choice is to give your block a signal through which
you can indicate it to update on relevant event, rather than have it rerun
idly.
To refresh all the blocks, run `kill -10 $(pidof dwmblocks)` or `pkill -SIGUSR1 dwmblocks`. For example, the volume block has the update signal `5` by default. I run
`kill -39 $(pidof dwmblocks)` alongside my volume shortcuts in `dwm` to only
update it when relevant. Just add `34` to your signal number! You could also
run `pkill -RTMIN+5 dwmblocks`, but it's slower.
To refresh all the blocks, run `kill -10 $(pidof dwmblocks)` or
`pkill -SIGUSR1 dwmblocks`.
> All blocks must have different signal numbers! > All blocks must have different signal numbers!
### Clickable blocks ### Clickable blocks
Like `i3blocks`, this build allows you to build in additional actions into your scripts in response to click events. You can check out [my status bar scripts](https://github.com/UtkarshVerma/dotfiles/tree/main/.local/bin/statusbar) as references for using the `$BLOCK_BUTTON` variable.
To use this feature, define the `CLICKABLE_BLOCKS` feature macro in your `config.h`: Like `i3blocks`, this build allows you to build in additional actions into your
scripts in response to click events. You can check out
[my status bar scripts](https://github.com/UtkarshVerma/dotfiles/tree/main/.local/bin/statusbar)
as references for using the `$BLOCK_BUTTON` variable.
To use this feature, define the `CLICKABLE_BLOCKS` feature macro in your
`config.h`:
```c ```c
#define CLICKABLE_BLOCKS #define CLICKABLE_BLOCKS 1
``` ```
Apart from that, you need `dwm` to be patched with [statuscmd](https://dwm.suckless.org/patches/statuscmd/). Apart from that, you need `dwm` to be patched with
[statuscmd](https://dwm.suckless.org/patches/statuscmd/).
## Credits ## Credits
This work would not have been possible without [Luke's build of dwmblocks](https://github.com/LukeSmithxyz/dwmblocks) and [Daniel Bylinka's statuscmd patch](https://dwm.suckless.org/patches/statuscmd/).
This work would not have been possible without
[Luke's build of dwmblocks](https://github.com/LukeSmithxyz/dwmblocks) and
[Daniel Bylinka's statuscmd patch](https://dwm.suckless.org/patches/statuscmd/).

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config.c Normal file
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#include "config.h"
#include "block.h"
#include "util.h"
// clang-format off
Block blocks[] = {
{"sb-mail", 600 , 1 },
{"sb-music", 0, 2 },
{"sb-disk", 1800, 3 },
{"sb-memory", 10, 4 },
{"sb-loadavg", 5, 5 },
{"sb-mic", 0, 6 },
{"sb-record", 0, 7 },
{"sb-volume", 0, 8 },
{"sb-battery", 5, 9 },
{"sb-date", 1, 10},
};
// clang-format on
const unsigned short blockCount = LEN(blocks);

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#define CMDLENGTH 45 #pragma once
#define DELIMITER " "
#define CLICKABLE_BLOCKS
const Block blocks[] = { #define CLICKABLE_BLOCKS 1 // Enable clickability for blocks
BLOCK("sb-mail", 1800, 17), #define CMDLENGTH 45 // Number of characters that each block will output
BLOCK("sb-music", 0, 18), #define DELIMITER " " // Delimiter string used to separate blocks
BLOCK("sb-disk", 1800, 19), #define LEADING_DELIMITER 0 // Whether a leading separator should be used
BLOCK("sb-memory", 10, 20),
BLOCK("sb-loadavg", 5, 21),
BLOCK("sb-mic", 0, 26),
BLOCK("sb-record", 0, 27),
BLOCK("sb-volume", 0, 22),
BLOCK("sb-battery", 5, 23),
BLOCK("sb-date", 1, 24)
};

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inc/bar.h Normal file
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#pragma once
#include "block.h"
#include "config.h"
#include "util.h"
typedef struct {
char *current;
char *previous;
} BarStatus;
extern unsigned short debugMode;
void initStatus(BarStatus *);
void freeStatus(BarStatus *);
void writeStatus(BarStatus *);

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inc/block.h Normal file
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#pragma once
#define _GNU_SOURCE
#include "config.h"
typedef struct {
const char *command;
const unsigned int interval;
const unsigned int signal;
int pipe[2];
char output[CMDLENGTH * 4 + 1];
} Block;
extern Block blocks[];
extern const unsigned short blockCount;
void execBlock(const Block *, const char *);
void execBlocks(unsigned int);
void updateBlock(Block *);

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inc/util.h Normal file
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#pragma once
#include <unistd.h>
#define LEN(arr) (sizeof(arr) / sizeof(arr[0]))
#define MAX(a, b) (a > b ? a : b)
int gcd(int, int);
void closePipe(int[2]);
void trimUTF8(char*, unsigned int);

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inc/x11.h Normal file
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#pragma once
int setupX();
int closeX();
void setXRootName(char *);

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main.c
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#define _GNU_SOURCE
#include <X11/Xlib.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/signalfd.h>
#include <time.h>
#include <unistd.h>
#define LEN(arr) (sizeof(arr) / sizeof(arr[0]))
#define MAX(a, b) (a > b ? a : b)
#define BLOCK(cmd, interval, signal) \
{ "echo \"$(" cmd ")\"", interval, signal }
typedef const struct {
const char *command;
const unsigned int interval;
const unsigned int signal;
} Block;
#include "config.h"
#ifdef CLICKABLE_BLOCKS
#undef CLICKABLE_BLOCKS
#define CLICKABLE_BLOCKS 1
#else
#define CLICKABLE_BLOCKS 0
#endif
#ifdef LEADING_DELIMITER
#undef LEADING_DELIMITER
#define LEADING_DELIMITER 1
#else
#define LEADING_DELIMITER 0
#endif
static Display *dpy;
static Window root;
static unsigned short statusContinue = 1;
static struct epoll_event event;
static int pipes[LEN(blocks)][2];
static int timer = 0, timerTick = 0, maxInterval = 1;
static int signalFD;
static int epollFD;
static int execLock = 0;
// Longest UTF-8 character is 4 bytes long
static char outputs[LEN(blocks)][CMDLENGTH * 4 + 1 + CLICKABLE_BLOCKS];
static char
statusBar[2]
[LEN(blocks) * (LEN(outputs[0]) - 1) +
(LEN(blocks) - 1 + LEADING_DELIMITER) * (LEN(DELIMITER) - 1) + 1];
void (*writeStatus)();
int gcd(int a, int b) {
int temp;
while (b > 0) {
temp = a % b;
a = b;
b = temp;
}
return a;
}
void closePipe(int *pipe) {
close(pipe[0]);
close(pipe[1]);
}
void execBlock(int i, const char *button) {
// Ensure only one child process exists per block at an instance
if (execLock & 1 << i) return;
// Lock execution of block until current instance finishes execution
execLock |= 1 << i;
if (fork() == 0) {
close(pipes[i][0]);
dup2(pipes[i][1], STDOUT_FILENO);
close(pipes[i][1]);
if (button) setenv("BLOCK_BUTTON", button, 1);
execl("/bin/sh", "sh", "-c", blocks[i].command, (char *)NULL);
exit(EXIT_FAILURE);
}
}
void execBlocks(unsigned int time) {
for (int i = 0; i < LEN(blocks); i++)
if (time == 0 ||
(blocks[i].interval != 0 && time % blocks[i].interval == 0))
execBlock(i, NULL);
}
int getStatus(char *new, char *old) {
strcpy(old, new);
new[0] = '\0';
for (int i = 0; i < LEN(blocks); i++) {
#if LEADING_DELIMITER
if (strlen(outputs[i]))
#else
if (strlen(new) && strlen(outputs[i]))
#endif
strcat(new, DELIMITER);
strcat(new, outputs[i]);
}
return strcmp(new, old);
}
void updateBlock(int i) {
char *output = outputs[i];
char buffer[LEN(outputs[0]) - CLICKABLE_BLOCKS];
int bytesRead = read(pipes[i][0], buffer, LEN(buffer));
// Trim UTF-8 string to desired length
int count = 0, j = 0;
while (buffer[j] != '\n' && count < CMDLENGTH) {
count++;
// Skip continuation bytes, if any
char ch = buffer[j];
int skip = 1;
while ((ch & 0xc0) > 0x80) ch <<= 1, skip++;
j += skip;
}
// Cache last character and replace it with a trailing space
char ch = buffer[j];
buffer[j] = ' ';
// Trim trailing spaces
while (j >= 0 && buffer[j] == ' ') j--;
buffer[j + 1] = 0;
// Clear the pipe
if (bytesRead == LEN(buffer)) {
while (ch != '\n' && read(pipes[i][0], &ch, 1) == 1)
;
}
#if CLICKABLE_BLOCKS
if (bytesRead > 1 && blocks[i].signal > 0) {
output[0] = blocks[i].signal;
output++;
}
#endif
strcpy(output, buffer);
// Remove execution lock for the current block
execLock &= ~(1 << i);
}
void debug() {
// Only write out if text has changed
if (!getStatus(statusBar[0], statusBar[1])) return;
write(STDOUT_FILENO, statusBar[0], strlen(statusBar[0]));
write(STDOUT_FILENO, "\n", 1);
}
int setupX() {
dpy = XOpenDisplay(NULL);
if (!dpy) return 1;
root = DefaultRootWindow(dpy);
return 0;
}
void setRoot() {
// Only set root if text has changed
if (!getStatus(statusBar[0], statusBar[1])) return;
XStoreName(dpy, root, statusBar[0]);
XFlush(dpy);
}
void signalHandler() {
struct signalfd_siginfo info;
read(signalFD, &info, sizeof(info));
unsigned int signal = info.ssi_signo;
switch (signal) {
case SIGALRM:
// Schedule the next timer event and execute blocks
alarm(timerTick);
execBlocks(timer);
// Wrap `timer` to the interval [1, `maxInterval`]
timer = (timer + timerTick - 1) % maxInterval + 1;
return;
case SIGUSR1:
// Update all blocks on receiving SIGUSR1
execBlocks(0);
return;
}
for (int j = 0; j < LEN(blocks); j++) {
if (blocks[j].signal == signal - SIGRTMIN) {
char button[4]; // value can't be more than 255;
sprintf(button, "%d", info.ssi_int & 0xff);
execBlock(j, button);
break;
}
}
}
void termHandler() { statusContinue = 0; }
void setupSignals() {
sigset_t handledSignals;
sigemptyset(&handledSignals);
sigaddset(&handledSignals, SIGUSR1);
sigaddset(&handledSignals, SIGALRM);
// Append all block signals to `handledSignals`
for (int i = 0; i < LEN(blocks); i++)
if (blocks[i].signal > 0)
sigaddset(&handledSignals, SIGRTMIN + blocks[i].signal);
// Create a signal file descriptor for epoll to watch
signalFD = signalfd(-1, &handledSignals, 0);
event.data.u32 = LEN(blocks);
epoll_ctl(epollFD, EPOLL_CTL_ADD, signalFD, &event);
// Block all realtime and handled signals
for (int i = SIGRTMIN; i <= SIGRTMAX; i++) sigaddset(&handledSignals, i);
sigprocmask(SIG_BLOCK, &handledSignals, NULL);
// Handle termination signals
signal(SIGINT, termHandler);
signal(SIGTERM, termHandler);
// Avoid zombie subprocesses
struct sigaction sa;
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_NOCLDWAIT;
sigaction(SIGCHLD, &sa, 0);
}
void statusLoop() {
// Update all blocks initially
raise(SIGALRM);
struct epoll_event events[LEN(blocks) + 1];
while (statusContinue) {
int eventCount = epoll_wait(epollFD, events, LEN(events), -1);
for (int i = 0; i < eventCount; i++) {
unsigned short id = events[i].data.u32;
if (id < LEN(blocks))
updateBlock(id);
else
signalHandler();
}
if (eventCount != -1) writeStatus();
}
}
void init() {
epollFD = epoll_create(LEN(blocks));
event.events = EPOLLIN;
for (int i = 0; i < LEN(blocks); i++) {
// Append each block's pipe to `epollFD`
pipe(pipes[i]);
event.data.u32 = i;
epoll_ctl(epollFD, EPOLL_CTL_ADD, pipes[i][0], &event);
// Calculate the max interval and tick size for the timer
if (blocks[i].interval) {
maxInterval = MAX(blocks[i].interval, maxInterval);
timerTick = gcd(blocks[i].interval, timerTick);
}
}
setupSignals();
}
int main(const int argc, const char *argv[]) {
if (setupX()) {
fprintf(stderr, "dwmblocks: Failed to open display\n");
return 1;
}
writeStatus = setRoot;
for (int i = 0; i < argc; i++)
if (!strcmp("-d", argv[i])) writeStatus = debug;
init();
statusLoop();
XCloseDisplay(dpy);
close(epollFD);
close(signalFD);
for (int i = 0; i < LEN(pipes); i++) closePipe(pipes[i]);
return 0;
}

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#include "bar.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "block.h"
#include "x11.h"
void initStatus(BarStatus *status) {
const unsigned int statusLength =
(blockCount * (LEN(blocks[0].output) - 1)) +
(blockCount - 1 + LEADING_DELIMITER) * (LEN(DELIMITER) - 1);
status->current = (char *)malloc(statusLength);
status->previous = (char *)malloc(statusLength);
status->current[0] = '\0';
status->previous[0] = '\0';
}
void freeStatus(BarStatus *status) {
free(status->current);
free(status->previous);
}
int updateStatus(BarStatus *status) {
strcpy(status->previous, status->current);
status->current[0] = '\0';
for (int i = 0; i < blockCount; i++) {
Block *block = blocks + i;
if (strlen(block->output)) {
#if LEADING_DELIMITER
strcat(status->current, DELIMITER);
#else
if (status->current[0]) strcat(status->current, DELIMITER);
#endif
#if CLICKABLE_BLOCKS
if (!debugMode && block->signal) {
char signal[] = {block->signal, '\0'};
strcat(status->current, signal);
}
#endif
strcat(status->current, block->output);
}
}
return strcmp(status->current, status->previous);
}
void writeStatus(BarStatus *status) {
// Only write out if status has changed
if (!updateStatus(status)) return;
if (debugMode) {
printf("%s\n", status->current);
return;
}
setXRootName(status->current);
}

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#include "block.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
static int execLock = 0;
void execBlock(const Block *block, const char *button) {
unsigned short i = block - blocks;
// Ensure only one child process exists per block at an instance
if (execLock & 1 << i) return;
// Lock execution of block until current instance finishes execution
execLock |= 1 << i;
if (fork() == 0) {
close(block->pipe[0]);
dup2(block->pipe[1], STDOUT_FILENO);
close(block->pipe[1]);
if (button) setenv("BLOCK_BUTTON", button, 1);
FILE *file = popen(block->command, "r");
if (!file) {
printf("\n");
exit(EXIT_FAILURE);
}
// Buffer will hold both '\n' and '\0'
char buffer[LEN(block->output) + 1];
if (fgets(buffer, LEN(buffer), file) == NULL) {
// Send an empty line in case of no output
printf("\n");
exit(EXIT_SUCCESS);
}
pclose(file);
// Trim to the max possible UTF-8 capacity
trimUTF8(buffer, LEN(buffer));
printf("%s\n", buffer);
exit(EXIT_SUCCESS);
}
}
void execBlocks(unsigned int time) {
for (int i = 0; i < blockCount; i++) {
const Block *block = blocks + i;
if (time == 0 ||
(block->interval != 0 && time % block->interval == 0)) {
execBlock(block, NULL);
}
}
}
void updateBlock(Block *block) {
char buffer[LEN(block->output)];
int bytesRead = read(block->pipe[0], buffer, LEN(buffer));
// String from pipe will always end with '\n'
buffer[bytesRead - 1] = '\0';
strcpy(block->output, buffer);
// Remove execution lock for the current block
execLock &= ~(1 << (block - blocks));
}

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#define _GNU_SOURCE
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/signalfd.h>
#include "bar.h"
#include "block.h"
#include "util.h"
#include "x11.h"
static unsigned short statusContinue = 1;
unsigned short debugMode = 0;
static int epollFD, signalFD;
static int timerTick = 0, maxInterval = 1;
void signalHandler() {
struct signalfd_siginfo info;
read(signalFD, &info, sizeof(info));
unsigned int signal = info.ssi_signo;
static unsigned int timer = 0;
switch (signal) {
case SIGALRM:
// Schedule the next timer event and execute blocks
alarm(timerTick);
execBlocks(timer);
// Wrap `timer` to the interval [1, `maxInterval`]
timer = (timer + timerTick - 1) % maxInterval + 1;
return;
case SIGUSR1:
// Update all blocks on receiving SIGUSR1
execBlocks(0);
return;
}
for (int j = 0; j < blockCount; j++) {
const Block *block = blocks + j;
if (block->signal == signal - SIGRTMIN) {
char button[4]; // value can't be more than 255;
sprintf(button, "%d", info.ssi_int & 0xff);
execBlock(block, button);
break;
}
}
}
void termHandler() { statusContinue = 0; }
void setupSignals() {
sigset_t handledSignals;
sigemptyset(&handledSignals);
sigaddset(&handledSignals, SIGUSR1);
sigaddset(&handledSignals, SIGALRM);
// Append all block signals to `handledSignals`
for (int i = 0; i < blockCount; i++)
if (blocks[i].signal > 0)
sigaddset(&handledSignals, SIGRTMIN + blocks[i].signal);
// Create a signal file descriptor for epoll to watch
signalFD = signalfd(-1, &handledSignals, 0);
// Block all realtime and handled signals
for (int i = SIGRTMIN; i <= SIGRTMAX; i++) sigaddset(&handledSignals, i);
sigprocmask(SIG_BLOCK, &handledSignals, NULL);
// Handle termination signals
signal(SIGINT, termHandler);
signal(SIGTERM, termHandler);
// Avoid zombie subprocesses
struct sigaction signalAction;
signalAction.sa_handler = SIG_DFL;
sigemptyset(&signalAction.sa_mask);
signalAction.sa_flags = SA_NOCLDWAIT;
sigaction(SIGCHLD, &signalAction, 0);
}
void statusLoop() {
// Update all blocks initially
raise(SIGALRM);
BarStatus status;
initStatus(&status);
struct epoll_event events[blockCount + 1];
while (statusContinue) {
int eventCount = epoll_wait(epollFD, events, LEN(events), 100);
for (int i = 0; i < eventCount; i++) {
unsigned short id = events[i].data.u32;
if (id < blockCount) {
updateBlock(blocks + id);
} else {
signalHandler();
}
}
if (eventCount != -1) writeStatus(&status);
}
freeStatus(&status);
}
void init() {
epollFD = epoll_create(blockCount);
struct epoll_event event = {
.events = EPOLLIN,
};
for (int i = 0; i < blockCount; i++) {
// Append each block's pipe's read end to `epollFD`
pipe(blocks[i].pipe);
event.data.u32 = i;
epoll_ctl(epollFD, EPOLL_CTL_ADD, blocks[i].pipe[0], &event);
// Calculate the max interval and tick size for the timer
if (blocks[i].interval) {
maxInterval = MAX(blocks[i].interval, maxInterval);
timerTick = gcd(blocks[i].interval, timerTick);
}
}
setupSignals();
// Watch signal file descriptor as well
event.data.u32 = blockCount;
epoll_ctl(epollFD, EPOLL_CTL_ADD, signalFD, &event);
}
int main(const int argc, const char *argv[]) {
if (setupX()) {
fprintf(stderr, "dwmblocks: Failed to open display\n");
return 1;
}
for (int i = 0; i < argc; i++) {
if (!strcmp("-d", argv[i])) {
debugMode = 1;
break;
}
}
init();
statusLoop();
if (closeX())
fprintf(stderr, "%s\n", "dwmblocks: Failed to close display");
close(epollFD);
close(signalFD);
for (int i = 0; i < blockCount; i++) closePipe(blocks[i].pipe);
return 0;
}

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#include "util.h"
int gcd(int a, int b) {
int temp;
while (b > 0) {
temp = a % b;
a = b;
b = temp;
}
return a;
}
void closePipe(int pipe[2]) {
close(pipe[0]);
close(pipe[1]);
}
void trimUTF8(char* buffer, unsigned int size) {
int length = (size - 1) / 4;
int count = 0, j = 0;
char ch = buffer[j];
while (ch != '\0' && ch != '\n' && count < length) {
// Skip continuation bytes, if any
int skip = 1;
while ((ch & 0xc0) > 0x80) {
ch <<= 1;
skip++;
}
j += skip;
ch = buffer[j];
count++;
}
// Trim trailing newline and spaces
buffer[j] = ' ';
while (j >= 0 && buffer[j] == ' ') j--;
buffer[j + 1] = '\0';
}

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#include "x11.h"
#include <X11/Xlib.h>
static Display *display;
static Window rootWindow;
int setupX() {
display = XOpenDisplay(NULL);
if (!display) {
return 1;
}
rootWindow = DefaultRootWindow(display);
return 0;
}
int closeX() { return XCloseDisplay(display); }
void setXRootName(char *str) {
XStoreName(display, rootWindow, str);
XFlush(display);
}