Rewrite in state machine look

- Also add new option to control internal delay of programmatic key
  sequences, when they're necessary.

README.md

@@ -28,19 +28,36 @@ ESC when pressed alone is quite handy, specially in vi.
 ```
 $ git clone git@gitlab.com:interception/linux/plugins/caps2esc.git
 $ cd caps2esc
-$ mkdir build
-$ cd build
-$ cmake ..
-$ make
+$ cmake -B build -DCMAKE_BUILD_TYPE=Release
+$ cmake --build build
 ```
 
 ## Execution
 
+```
+caps2esc - transforming the most useless key ever in the most useful one
+
+usage: caps2esc [-h] [-m mode] [-t delay]
+
+options:
+    -h        show this message and exit
+    -t        delay used for key sequences (default: 20000 microseconds)
+    -m mode   0: default
+                 - caps as esc/ctrl
+                 - esc as caps
+              1: minimal
+                 - caps as esc/ctrl
+              2: useful on 60% layouts
+                 - caps as esc/ctrl
+                 - esc as grave accent
+                 - grave accent as caps
+```
+
 `caps2esc` is an [_Interception Tools_][interception-tools] plugin. A suggested
 `udevmon` job configuration is:
 
 ```yaml
-- JOB: "intercept -g $DEVNODE | caps2esc | uinput -d $DEVNODE"
+- JOB: intercept -g $DEVNODE | caps2esc | uinput -d $DEVNODE
   DEVICE:
     EVENTS:
       EV_KEY: [KEY_CAPSLOCK, KEY_ESC]
@@ -50,11 +67,37 @@ $ make
 For more information about the [_Interception Tools_][interception-tools], check
 the project's website.
 
+## Mouse button support
+
+After _Interception Tools_ 0.3, `caps2esc` can work with mouse clicks. An
+example configuration taken from my laptop:
+
+```yaml
+SHELL: [zsh, -c]
+---
+- JOB: mux -c caps2esc
+- JOB:
+    - intercept -g $DEVNODE | mux -o caps2esc
+    - mux -i caps2esc | caps2esc | uinput -d $DEVNODE
+  DEVICE:
+    LINK: /dev/input/by-path/platform-i8042-serio-0-event-kbd
+- JOB:
+    - intercept $DEVNODE | mux -o caps2esc
+  DEVICE:
+    LINK: /dev/input/by-path/platform-i8042-serio-4-event-mouse
+```
+
+For more information on the topic, check the [_Interception Tools_
+README][interception-tools] about usage of the `mux` tool and device specific
+setups.
+
 ## Installation
 
-I'm maintaining an Archlinux package on AUR:
+It's available from [community](https://archlinux.org/packages/community/x86_64/interception-caps2esc/):
 
-- <https://aur.archlinux.org/packages/interception-caps2esc>
+```
+$ pacman -S interception-caps2esc
+```
 
 I don't use Ubuntu and recommend Archlinux instead, as it provides the AUR, so I
 don't maintain PPAs. For more information on Ubuntu/Debian installation check
@@ -75,7 +118,7 @@ As always, there's always a caveat:
 I can't recall when I started using CAPSLOCK as both ESC and CTRL but it has
 been quite some time already. It started when I was on OS X where it was quite
 easy to achieve using the [Karabiner][], which already provides an option to
-turn CTRL into CTRL/ESC (which can be coupled with OS X system settings that
+turn CTRL into ESC/CTRL (which can be coupled with OS X system settings that
 turn CAPSLOCK into CTRL).
 
 Moving on, permanently making Linux my home, I searched and tweaked a similar

caps2esc.c

@@ -6,21 +6,34 @@
 
 // clang-format off
 const struct input_event
-esc_up          = {.type = EV_KEY, .code = KEY_ESC,      .value = 0},
-ctrl_up         = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 0},
-capslock_up     = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 0},
-esc_down        = {.type = EV_KEY, .code = KEY_ESC,      .value = 1},
-ctrl_down       = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 1},
-capslock_down   = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 1},
-esc_repeat      = {.type = EV_KEY, .code = KEY_ESC,      .value = 2},
-ctrl_repeat     = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 2},
-capslock_repeat = {.type = EV_KEY, .code = KEY_CAPSLOCK, .value = 2},
-syn             = {.type = EV_SYN, .code = SYN_REPORT,   .value = 0};
+syn         = {.type = EV_SYN, .code = SYN_REPORT,   .value = 0},
+esc_up      = {.type = EV_KEY, .code = KEY_ESC,      .value = 0},
+ctrl_up     = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 0},
+esc_down    = {.type = EV_KEY, .code = KEY_ESC,      .value = 1},
+ctrl_down   = {.type = EV_KEY, .code = KEY_LEFTCTRL, .value = 1};
 // clang-format on
 
-int equal(const struct input_event *first, const struct input_event *second) {
-    return first->type == second->type && first->code == second->code &&
-           first->value == second->value;
+void print_usage(FILE *stream, const char *program) {
+    // clang-format off
+    fprintf(stream,
+            "caps2esc - transforming the most useless key ever in the most useful one\n"
+            "\n"
+            "usage: %s [-h] [-m mode] [-t delay]\n"
+            "\n"
+            "options:\n"
+            "    -h        show this message and exit\n"
+            "    -t        delay used for key sequences (default: 20000 microseconds)\n"
+            "    -m mode   0: default\n"
+            "                 - caps as esc/ctrl\n"
+            "                 - esc as caps\n"
+            "              1: minimal\n"
+            "                 - caps as esc/ctrl\n"
+            "              2: useful on 60%% layouts\n"
+            "                 - caps as esc/ctrl\n"
+            "                 - esc as grave accent\n"
+            "                 - grave accent as caps\n",
+            program);
+    // clang-format on
 }
 
 int read_event(struct input_event *event) {
@@ -32,9 +45,45 @@ void write_event(const struct input_event *event) {
         exit(EXIT_FAILURE);
 }
 
-int main(void) {
-    int capslock_is_down = 0, esc_give_up = 0;
+void write_event_with_mode(struct input_event *event, int mode) {
+    switch (mode) {
+        case 0:
+            if (event->code == KEY_ESC)
+                event->code = KEY_CAPSLOCK;
+            break;
+        case 2:
+            switch (event->code) {
+                case KEY_ESC:
+                    event->code = KEY_GRAVE;
+                    break;
+                case KEY_GRAVE:
+                    event->code = KEY_CAPSLOCK;
+                    break;
+            }
+            break;
+    }
+    write_event(event);
+}
+
+int main(int argc, char *argv[]) {
+    int opt, mode = 0, delay = 20000;
+    while ((opt = getopt(argc, argv, "ht:m:")) != -1) {
+        switch (opt) {
+            case 'h':
+                return print_usage(stdout, argv[0]), EXIT_SUCCESS;
+            case 't':
+                delay = atoi(optarg);
+                continue;
+            case 'm':
+                mode = atoi(optarg);
+                continue;
+        }
+
+        return print_usage(stderr, argv[0]), EXIT_FAILURE;
+    }
+
     struct input_event input;
+    enum { START, CAPSLOCK_HELD, CAPSLOCK_IS_CTRL } state = START;
 
     setbuf(stdin, NULL), setbuf(stdout, NULL);
 
@@ -47,38 +96,40 @@ int main(void) {
             continue;
         }
 
-        if (capslock_is_down) {
-            if (equal(&input, &capslock_down) ||
-                equal(&input, &capslock_repeat))
-                continue;
-
-            if (equal(&input, &capslock_up)) {
-                capslock_is_down = 0;
-                if (esc_give_up) {
-                    esc_give_up = 0;
-                    write_event(&ctrl_up);
-                    continue;
-                }
-                write_event(&esc_down);
-                write_event(&syn);
-                usleep(20000);
-                write_event(&esc_up);
-                continue;
-            }
-
-            if (!esc_give_up && input.value) {
-                esc_give_up = 1;
-                write_event(&ctrl_down);
-                write_event(&syn);
-                usleep(20000);
-            }
-        } else if (equal(&input, &capslock_down)) {
-            capslock_is_down = 1;
-            continue;
+        switch (state) {
+            case START:
+                if (input.code == KEY_CAPSLOCK && input.value)
+                    state = CAPSLOCK_HELD;
+                else
+                    write_event_with_mode(&input, mode);
+                break;
+            case CAPSLOCK_HELD:
+                if (input.code == KEY_CAPSLOCK) {
+                    if (input.value == 0) {
+                        write_event(&esc_down);
+                        write_event(&syn);
+                        usleep(delay);
+                        write_event(&esc_up);
+                        state = START;
+                    }
+                } else if (input.value == 1) {
+                    write_event(&ctrl_down);
+                    write_event(&syn);
+                    usleep(delay);
+                    write_event_with_mode(&input, mode);
+                    state = CAPSLOCK_IS_CTRL;
+                } else
+                    write_event_with_mode(&input, mode);
+                break;
+            case CAPSLOCK_IS_CTRL:
+                if (input.code == KEY_CAPSLOCK) {
+                    input.code = KEY_LEFTCTRL;
+                    write_event(&input);
+                    if (input.value == 0)
+                        state = START;
+                } else
+                    write_event_with_mode(&input, mode);
+                break;
         }
-
-        if (input.code == KEY_ESC)
-            input.code = KEY_CAPSLOCK;
-        write_event(&input);
     }
 }