Implement support for PCRE regular expressions for all criteria (for_window, commands, assignments)

include/all.h

@@ -64,5 +64,6 @@
 #include "output.h"
 #include "ewmh.h"
 #include "assignments.h"
+#include "regex.h"
 
 #endif

include/data.h

@@ -10,6 +10,7 @@
 #include <xcb/randr.h>
 #include <xcb/xcb_atom.h>
 #include <stdbool.h>
+#include <pcre.h>
 
 #ifndef _DATA_H
 #define _DATA_H
@@ -137,6 +138,21 @@ struct Ignore_Event {
     SLIST_ENTRY(Ignore_Event) ignore_events;
 };
 
+/**
+ * Regular expression wrapper. It contains the pattern itself as a string (like
+ * ^foo[0-9]$) as well as a pointer to the compiled PCRE expression and the
+ * pcre_extra data returned by pcre_study().
+ *
+ * This makes it easier to have a useful logfile, including the matching or
+ * non-matching pattern.
+ *
+ */
+struct regex {
+    const char *pattern;
+    pcre *regex;
+    pcre_extra *extra;
+};
+
 /******************************************************************************
  * Major types
  *****************************************************************************/
@@ -277,12 +293,11 @@ struct Window {
 };
 
 struct Match {
-    char *title;
-    int title_len;
-    char *application;
-    char *class;
-    char *instance;
-    char *mark;
+    struct regex *title;
+    struct regex *application;
+    struct regex *class;
+    struct regex *instance;
+    struct regex *mark;
     enum {
         M_DONTCHECK = -1,
         M_NODOCK = 0,

include/regex.h

@@ -0,0 +1,28 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ */
+#ifndef _REGEX_H
+#define _REGEX_H
+
+/**
+ * Creates a new 'regex' struct containing the given pattern and a PCRE
+ * compiled regular expression. Also, calls pcre_study because this regex will
+ * most likely be used often (like for every new window and on every relevant
+ * property change of existing windows).
+ *
+ * Returns NULL if the pattern could not be compiled into a regular expression
+ * (and ELOGs an appropriate error message).
+ *
+ */
+struct regex *regex_new(const char *pattern);
+
+/**
+ * Checks if the given regular expression matches the given input and returns
+ * true if it does. In either case, it logs the outcome using LOG(), so it will
+ * be visible without any debug loglevel.
+ *
+ */
+bool regex_matches(struct regex *regex, const char *input);
+
+#endif