various improvements

Makefile

@@ -1,18 +1,19 @@
-showkeys: showkeys.c showkeys.h keystack.o
-	gcc -g -Wall showkeys.c keystack.o -o showkeys -lX11 -lxosd -lpthread -lXext -lX11 -lXinerama -lXtst
+LDFLAGS = -lX11 -lxosd -lpthread -lXext -lX11 -lXinerama -lXtst
+SOURCES = keystack.c showkeys.c
+HEADERS = config.h keystack.h showkeys.h die.h
+CC = gcc
+CFLAGS = -g -Wall -Wextra -fdiagnostics-color=auto
+LD = gcc
 
-
-keystack.o: keystack.c keystack.h
-	gcc -c -g keystack.c
+all: showkeys
 
 clean:
-	rm showkeys keystack.o record-attempt record-example
+	rm -f showkeys *.o
 
-check-syntax:
-	gcc -Wall -o nul -S ${CHK_SOURCES}
+.c.o:
+	$(CC) $(CFLAGS) -c -o $@ $<
 
-record-attempt: record-attempt.c
-	gcc -g -Wall record-attempt.c -L/usr/lib -lXtst -lxosd -lpthread -lXext -lX11 -lXinerama -o record-attempt
+$(SOURCES:.c=.o): $(HEADERS)
 
-record-example: record-example.c
-	gcc -g -Wall record-example.c -L/usr/lib -lXtst -lxosd -lpthread -lXext -lX11 -lXinerama -o record-example
+showkeys: $(SOURCES:.c=.o)
+	$(LD) -o $@ $^ $(LDFLAGS)

config.h

@@ -1,9 +1,17 @@
 /*
   Config header for showkeys.c
 */
+#ifndef CONFIG_H
+#define CONFIG_H
+
+/* Number of OSD lines on the screen */
+#define NKEYS 10
+
+/* Maximum length of one OSD line */
+#define OSDLEN 15
 
 /* Display font, select a font using 'xfontsel -scaled' */
-#define SK_FONT     "-*-courier*-*-*-*-*-60-*-*-*-*-*-*-*"
+#define SK_FONT     "-*-latin modern sans-*-r-*-*-60-*-*-*-*-*-*-*"
 
 /* Display position, possible values: XOSD_top, XOSD_bottom */
 #define SK_POS      XOSD_bottom
@@ -36,3 +44,9 @@
    to: #undef SK_NO_REPEATS. */
 #define SK_NO_REPEATS
 
+/* Define CAPS_IS_CONTROL if the caps lock key should be understood as a control
+ * modifier. */
+#define CAPS_IS_CONTROL
+
+
+#endif

die.h

@@ -0,0 +1,14 @@
+/* Showkeys
+   Copyright Noufal Ibrahim <[email protected]> 2011
+   Copyright Raphael Poss <[email protected]> 2020
+
+   Licensed under the GPLv3 : http://www.gnu.org/licenses/gpl.txt
+
+   Please see LICENSE file for complete license.
+*/
+#ifndef DIE_H
+#define DIE_H
+
+extern void die(const char*);
+
+#endif

keystack.c

@@ -1,73 +1,111 @@
-/* Showkeys 
+/* Showkeys
    Copyright Noufal Ibrahim <[email protected]> 2011
 
    Licensed under the GPLv3 : http://www.gnu.org/licenses/gpl.txt
 
    Please see LICENSE file for complete license.
 */
 
+#define _GNU_SOURCE
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "keystack.h"
+#include "die.h"
+#include "config.h"
 
+// push_back frees up the spot in the stack at the specified index,
+// by pulling all the entries before that by one spot.
+// The first entry is popped (and its string deallocated).
 static void
 push_back(KeyStack *stack, int index)
 {
-  int i;
-  free(stack->keystrokes[0].keyname);
-  for (i=0; i<index; i++) 
-    stack->keystrokes[i] = stack->keystrokes[i+1];
+    free(stack->keystrokes[0].keyname);
+    free(stack->keystrokes[0].buf);
+
+    for (int i = 0; i < index; i++)
+	stack->keystrokes[i] = stack->keystrokes[i+1];
+
+    stack->keystrokes[index].keyname = 0;
+}
+
+void
+clear_stack(KeyStack *stack)
+{
+    for (int i = 0; i < stack->pos; i++) {
+	free(stack->keystrokes[i].keyname);
+	free(stack->keystrokes[i].buf);
+	stack->keystrokes[i].keyname = 0;
+    }
+    stack->pos = -1;
 }
 
 KeyStack *
-create_keystack(int size) 
+create_keystack(int size)
 {
-  int i;
-  KeyStack *retval = NULL;
-  KeyStroke *stack = NULL;
-
-  stack = (KeyStroke *)malloc(sizeof(KeyStroke) * size);
-  for (i=0; i<size; i++) {
-    stack[i].keyname = NULL;
-    stack[i].times = 0;
-  }
+    KeyStack *retval = NULL;
+    KeyStroke *stack = NULL;
 
-  retval = (KeyStack *)malloc(sizeof(KeyStack));
-  retval->size = size;
-  retval->pos = -1;
-  retval->keystrokes = stack;
+    stack = (KeyStroke *)malloc(sizeof(KeyStroke) * size);
+    if (!stack)
+	die("malloc");
 
-  return retval;
+    for (int i = 0; i < size; i++) {
+	stack[i].keyname = NULL;
+	stack[i].times = 0;
+    }
+
+    retval = (KeyStack *)malloc(sizeof(KeyStack));
+    if (!retval)
+	die("malloc");
+
+    retval->size = size;
+    retval->pos = -1;
+    retval->keystrokes = stack;
+
+    return retval;
 }
 
 void
 push(KeyStack *stack, char *keyname)
 {
-  int index;
-  KeyStroke *last;
-  char *last_key;
-
-  last = &stack->keystrokes[stack->pos];
-  last_key = last->keyname;
-  index = stack->pos + 1;
+  int index = stack->pos + 1;
 
 #ifdef SK_NO_REPEATS
-  if (index && ! strcmp (last_key, keyname)) {
-    /* If the same as the top of the stack, increment count */
-    last->times ++;
+  if (index >= 1 && !strcmp(stack->keystrokes[index-1].keyname, keyname)) {
+      /* If the same as the top of the stack, increment count */
+      stack->keystrokes[index-1].times++;
   } else {
 #endif
-    /* Add a new entry */
-    if (index == stack->size) {
-      push_back(stack, stack->pos);
-      index = stack->size-1;
-    }
-    stack->keystrokes[index].keyname = keyname;
-    stack->keystrokes[index].times = 1;
-    stack->pos = index;
+      /* Add a new entry. */
+      // Can we add it to the previous line?
+      if (index >= 1 && // We have a previous line already.
+	  stack->keystrokes[index-1].times < 2 && // Not more than one press of the last key.
+	  strcmp(stack->keystrokes[index-1].keyname, "Ret") != 0 && // Only if the last key was not "Enter".
+	  strlen(stack->keystrokes[index-1].buf) + strlen(keyname) + 1 < OSDLEN // The combination fits.
+	  ) {
+	  char *newbuf;
+	  if (-1 == asprintf(&newbuf, "%s %s", stack->keystrokes[index-1].buf, keyname))
+	      die("asprintf");
+	  free(stack->keystrokes[index-1].keyname);
+	  free(stack->keystrokes[index-1].buf);
+	  stack->keystrokes[index-1].buf = newbuf;
+	  stack->keystrokes[index-1].keyname = keyname;
+      } else {
+	  // Adding to the last line? scroll everything first up.
+	  if (index == stack->size) {
+	      push_back(stack, stack->pos);
+	      index = stack->size - 1;
+	  }
+
+	  // Now create a new line.
+	  stack->keystrokes[index].buf = strdup(keyname);
+	  stack->keystrokes[index].keyname = keyname;
+	  stack->keystrokes[index].times = 1;
+	  stack->pos = index;
+      }
 #ifdef SK_NO_REPEATS
   }
 #endif
@@ -77,9 +115,8 @@ push(KeyStack *stack, char *keyname)
 void
 display_keystack(KeyStack *stack)
 {
-  int i;
   printf("---- Keystack ----\n");
-  for (i = 0; i <= stack->pos; i++) {
+  for (int i = 0; i <= stack->pos; i++) {
     printf("%s %d times\n", stack->keystrokes[i].keyname, stack->keystrokes[i].times);
   }
   printf("---- -------- ----\n\n");

keystack.h

@@ -1,27 +1,46 @@
-/* Showkeys 
+/* Showkeys
    Copyright Noufal Ibrahim <[email protected]> 2011
+   Copyright Raphael Poss <[email protected]> 2020
 
    Licensed under the GPLv3 : http://www.gnu.org/licenses/gpl.txt
 
    Please see LICENSE file for complete license.
 */
-#define NKEYS 10
+#ifndef KEYSTACK_H
+#define KEYSTACK_H
 
+#include "config.h"
+
+// KeyStroke represents one line in the OSD output.
 typedef struct {
-  char *keyname;
-  int times;
+    // keyname is the string returned by the X lookup function for the
+    // last key, possibly prefixed by a representation of modifiers.
+    // It identifies the last key event.
+    char *keyname;
+    // buf is the string to be printed on the screen.
+    char *buf;
+
+    // times is the number of times the last key has been pressed.
+    int times;
 } KeyStroke;
 
 typedef struct {
-  int size;
-  int pos;
-  KeyStroke *keystrokes;
+    // size is the total (allocated) number of entries in keystrokes
+    // below.
+    int size;
+    // pos is the index of the last used entry in
+    // keystrokes. Initially -1 to indicate no entry has been used
+    // yet.
+    int pos;
+    // keystrokes is the array of allocated keystrokes struct.
+    // There is one entry per OSD line, up to and including the
+    // entry pointed to by pos.
+    KeyStroke *keystrokes;
 } KeyStack;
 
-
-
 KeyStack *create_keystack();
 void push(KeyStack *, char *);
+void clear_stack(KeyStack *);
 void display_keystack(KeyStack *);
 
-
+#endif