qpkg: added parsing and recording of Provides data

- pkg.h (enum flags): new flags QPKG_PROVIDED to indicate that the
  package is only a provision, not an installable package
- fixup.h, fixup.c (complete_provisions): search for provisions that do
  not have a real package associated with them, create a package for
  them, and mark it as QPKG_PROVIDED
- qpkg.c (do_fixups): invoke complete_provisions
- pkg.h (struct pkg): add list of (virtual or real) packages a given
  package provides
- pkg.c (new_pkg): initialize pkg->provides
- pkg.c (free_pkg): deallocate pkg->provides
- gobble.c (gobble_buf): parse the list of packages a package provides
- TODO: updated status of Provides support

qpkg/TODO

@@ -6,6 +6,9 @@ Still left to do
 
 - handle Provides:
 
+  Update: Provides data is now parsed and properly integrated in the
+  package database, but not yet used to resolve prerequisites.
+
 - sort prerequisites such that they can be installed in the specified order
 
 - consider Architecture:

qpkg/fixup.c

@@ -42,3 +42,14 @@ void sort_versions(void)
 					(*b)->more = tmp;
 				}
 }
+
+
+void complete_provisions(void)
+{
+	struct jrb *n;
+
+	for (n = jrb_first(packages->root); n != jrb_nil(packages->root);
+	    n = jrb_next(n))
+		if (!n->val)
+			new_pkg(n)->flags |= QPKG_PROVIDED;
+}

qpkg/fixup.h

@@ -14,5 +14,6 @@
 #define	FIXUP_H
 
 void sort_versions(void);
+void complete_provisions(void);
 
 #endif /* !FIXUP_H */

qpkg/gobble.c

@@ -321,8 +321,13 @@ architecture:
 	goto skip_data;
 
 provides:
-	/* @@@ later */
+	anchor = &pkg->provides;
-	goto skip_data;
+	/*
+	 * There should never be a version in the provisions, so it's a bit
+	 * wasteful to use a structure that has a version field. But then, code
+	 * reuse is nice, too.
+	 */
+	goto list_with_version;
 
 status:
 	pkg->flags |= QPKG_INSTALLED;

qpkg/pkg.c

@@ -30,7 +30,7 @@ struct pkg *new_pkg(struct jrb *jrb)
 	jrb->val = pkg;
 	pkg->version = NULL;
 	pkg->arch = NULL;
-	pkg->conflicts = pkg->depends = NULL;
+	pkg->conflicts = pkg->depends = pkg->provides = NULL;
 	pkg->filename = NULL;
 	pkg->flags = 0;
 	pkg->mark = 0;
@@ -55,5 +55,6 @@ void free_pkg(struct pkg *pkg)
 {
 	free_refs(pkg->conflicts);
 	free_refs(pkg->depends);
+	free_refs(pkg->provides);
 	free(pkg);
 }

qpkg/pkg.h

@@ -19,8 +19,9 @@
 
 
 enum flags {
-	/* parse-time flags */
+	/* parse-time and fixup-time flags */
 	QPKG_INSTALLED	= 1 << 0,	/* installed on target */
+	QPKG_PROVIDED	= 1 << 1,	/* virtual package */
 
 	/* run-time flags */
 	QPKG_ADDING	= 1 << 10,	/* resolving dependencies */
@@ -47,6 +48,7 @@ struct pkg {
 	const char *arch;
 	struct ref *conflicts;
 	struct ref *depends;
+	struct ref *provides;
 	const char *filename;
 	int flags;		/* see enum flags */
 	struct pkg *more;

qpkg/qpkg.c

@@ -121,6 +121,7 @@ static void find_prereq(const char *name, const char *version)
 static void do_fixups(void)
 {
 	sort_versions();
+	complete_provisions();
 }