lib: add ability to template repo urls with {arch}

{arch} will be replaced with XBPS_TARGET_ARCH (if set) or XBPS_ARCH

include/xbps.h.in

@@ -1601,6 +1601,16 @@ bool xbps_repo_store(struct xbps_handle *xhp, const char *url);
  */
 bool xbps_repo_remove(struct xbps_handle *xhp, const char *url);
 
+/**
+ * Converts \a {arch} in a repository URI to the correct architecture.
+ *
+ * @param[in] xhp Pointer to the xbps_handle struct.
+ * @param[in] url Repository URI to format.
+ *
+ * @return The formatted repository URI.
+ */
+char *xbps_repo_format(struct xbps_handle *xhp, const char *url);
+
 /**
  * Creates a lock for a local repository to obtain exclusive access (write).
  *

lib/initend.c

@@ -163,6 +163,15 @@ xbps_init(struct xbps_handle *xhp)
 			xhp->flags |= XBPS_FLAG_DISABLE_SYSLOG;
 	}
 
+	for (unsigned int i = 0; i < xbps_array_count(xhp->repositories); i++) {
+		const char *url = NULL;
+		xbps_array_get_cstring_nocopy(xhp->repositories, i, &url);
+		xbps_array_set_cstring_nocopy(xhp->repositories, i, xbps_repo_format(xhp, url));
+	}
+
+	xbps_dbg_printf("Native architecture is %s\n", xhp->native_arch);
+	xbps_dbg_printf("Target architecture is %s\n", xhp->target_arch);
+
 	if (xhp->flags & XBPS_FLAG_DEBUG) {
 		const char *repodir;
 		for (unsigned int i = 0; i < xbps_array_count(xhp->repositories); i++) {

lib/repo.c

@@ -37,6 +37,7 @@
 #include <openssl/ssl.h>
 #include <openssl/pem.h>
 
+#include "xbps/fmt.h"
 #include "xbps_api_impl.h"
 
 /**
@@ -193,6 +194,65 @@ repo_open_remote(struct xbps_repo *repo)
 	return rv;
 }
 
+static int
+repo_fmt(FILE *fp, const struct xbps_fmt_var *var, void *data)
+{
+	struct xbps_handle *xhp = data;
+	const char *arch;
+
+	if (xhp->target_arch)
+		arch = xhp->target_arch;
+	else
+		arch = xhp->native_arch;
+
+	if (strcmp(var->name, "arch") == 0) {
+		return xbps_fmt_print_string(var, arch, 0, fp);
+	}
+	return 0;
+}
+
+char *
+xbps_repo_format(struct xbps_handle *xhp, const char *url)
+{
+	struct xbps_fmt *fmt = NULL;
+	FILE *fmt_stream;
+	char *fmt_buf;
+	size_t len;
+	int r;
+
+	assert(xhp);
+	assert(url);
+
+	if (!strstr(url, "{arch}"))
+		return strdup(url);
+
+	xbps_dbg_printf("Processing templated repository: %s\n", url);
+
+	fmt_stream = open_memstream(&fmt_buf, &len);
+	if (!fmt_stream) {
+		xbps_error_printf("failed to open buffer: %s\n", strerror(errno));
+		goto fmtout;
+	}
+	fmt = xbps_fmt_parse(url);
+	if (!fmt) {
+		xbps_error_printf("failed to parse format for repo '%s': %s\n", url, strerror(errno));
+		goto fmtout;
+	}
+	r = xbps_fmt(fmt, repo_fmt, xhp, fmt_stream);
+	if (r < 0) {
+		xbps_error_printf("failed to format repo '%s': %s\n", url, strerror(-r));
+		goto fmtout;
+	}
+	fflush(fmt_stream);
+	return fmt_buf;
+
+fmtout:
+	fclose(fmt_stream);
+	xbps_fmt_free(fmt);
+	free(fmt_buf);
+	return NULL;
+}
+
 static struct xbps_repo *
 repo_open_with_type(struct xbps_handle *xhp, const char *url, const char *name)
 {