Add relative directory parsing

As of now, when using `-r' or `-R', relative directories can be used.
This *does not* include locations starting with `~', those still need
to be handled by your shell.

Because every repo is treated as a possible relative path, and thus
passed on to `realpath', the paths have become very uniform.  This
means that it will now only register and unregister paths that don't
have a trailing `/'.  This is not true during usage, so those paths
still work, but they can't be removed by gitto, and adding them again
will create a duplicate entry.

* gitto/Makefile (objects): Add `path.scm' and `path.go'.

  (.PHONY): Add `all' as a phony target.

  (all): New target, compiles all `.go' targets.

  ($(filter %.go,$(objects))): Use `env' to run guild so that include
  paths are setup properly.

* gitto/main.scm (gitto): Use new `(gitto path)' module, it contains
  the `realpath' function.

  (register-repository):
  (remove-repository): Always pass REPOSITORY through `realpath' and
  use the result.

* gitto/path.scm: New file. Loads the `libguile-gitto-path' extension
  and exports its `realpath' function.

* src/Makefile (CFLAGS):
  (LDFLAGS): Use `pkg-config' to gather the necessary values for guile.

  (libguile-gitto-path.so): New guile extension, wraps the `readline'
  POSIX function.

* src/gitto-path.c: New file, wraps and exports the `realpath' POSIX
  function from `stdlib.h'.

3 files changed, 39 insertions, 4 deletions

diff --git a/src/.gitignore b/src/.gitignore
new file mode 100644
index 0000000..9d22eb4
--- /dev/null
+++ b/src/.gitignore
@@ -0,0 +1,2 @@
+*.o
+*.so
diff --git a/src/Makefile b/src/Makefile
index 61946a0..584374e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,11 +1,23 @@
 DESTDIR ?= /usr/local
+CFLAGS = $(shell pkg-config --cflags guile-2.0) -fPIC
+LDFLAGS = $(shell pkg-config --libs guile-2.0)
 
-all:
+objects = gitto-path.o
+
+all: libguile-gitto-path.so
 
 .PHONY: install uninstall
 
-install: gitto
+libguile-gitto-path.so: gitto-path.o
+	$(CC) $(CFLAGS) -shared -o libguile-gitto-path.so $^
+
+install-gitto: gitto
 	install -Dm 755 $^ ${DESTDIR}/bin/$^
+install-libguile-gitto-path: libguile-gitto-path.so
+	install -Dm 755 $^ \
+		$(shell pkg-config guile-2.0 --variable=extensiondir)/$^
+install: install-gitto install-libguile-gitto-path
 
-uninstall: gitto
-	rm -f ${DESTDIR}/bin/$^
+uninstall:
+	rm -f ${DESTDIR}/bin/gitto
+	rm -f $(shell pkg-config guile-2.0 --variable=extensiondir)/libguile-gitto-path.so
diff --git a/src/gitto-path.c b/src/gitto-path.c
new file mode 100644
index 0000000..ad1400a
--- /dev/null
+++ b/src/gitto-path.c
@@ -0,0 +1,21 @@
+#include <stdlib.h>
+#include <libguile.h>
+
+SCM
+realpath_wrapper(SCM str)
+{
+    char *path = scm_to_locale_string(str);
+    char *resolved_path = realpath(path, NULL);
+    SCM scm_resolved_path = scm_from_locale_string(resolved_path);
+
+    free(path);
+    free(resolved_path);
+
+    return scm_resolved_path;
+}
+
+void
+init_gitto()
+{
+    scm_c_define_gsubr("realpath", 1, 0, 0, realpath_wrapper);
+}