xbps-src: update_check.sh: check distfile existence for kde

* KDE distfile storage is based on versionned "folder".
An existing folder_version does not mean that the corresponding
distifile exists, so let's check its existence.

* wider scope for KDE urls that will use that rule.
Fine for plenty other packages, except kdb that don't follow
this hierarchy (yet)

common/xbps-src/shutils/update_check.sh

@@ -4,6 +4,7 @@ update_check() {
     local i p url sfname lpname bbname githubname rx found_version consider
     local update_override=$XBPS_SRCPKGDIR/$XBPS_TARGET_PKG/update
     local original_pkgname=$pkgname
+    local urlpfx urlsfx
 
     if [ -r $update_override ]; then
         . $update_override
@@ -27,6 +28,35 @@ update_check() {
     else
         printf '%s\n' "$site"
     fi |
+    # filter loop: if version are "folder" name based,
+    # substitute original url by every folder based ones (expand)
+    while IFS= read -r url; do
+        rx=
+        urlpfx="${url}"
+        urlsfx=
+        case "$url" in
+            *download.kde.org/stable/applications/*|*download.kde.org/stable/frameworks/*|*download.kde.org/stable/plasma/*|\
+                *download.kde.org/stable/kdevelop/*|*download.kde.org/stable/krita/*|*download.kde.org/stable/clazy/*|\
+                *download.kde.org/stable/digikam/*|*download.kde.org/stable/phonon/*)
+                urlpfx="${url%%${version%.*}*}"
+                urlsfx="${url##${urlpfx}${version%.*}}"
+                urlsfx="${urlsfx#.*/}"
+                urlsfx="/${urlsfx#/}"
+                rx='href="\K[\d\.]+(?=/")'
+                ;;
+        esac
+        if [ -z "$rx" ]; then
+            # default case: don't rewrite url
+            printf '%s\n' "$url"
+        else
+            # substitute url if needed
+            if [ -n "$XBPS_UPDATE_CHECK_VERBOSE" ]; then
+                echo "(folder) fetching $urlpfx" 1>&2
+            fi
+            curl -A "xbps-src-update-check/$XBPS_SRC_VERSION" --max-time 10 -Lsk "$urlpfx" |
+                grep -Po -i "$rx" | xargs -r -n 1 -I @@ printf '%s\n' "${urlpfx}@@${urlsfx}"
+        fi
+    done |
     while IFS= read -r url; do
         rx=
         if [ -z "$site" ]; then
@@ -64,9 +94,6 @@ update_check() {
                 rx=linux-'\K'${version%.*}'[\d.]+(?=\.tar\.xz)';;
             *cran.r-project.org/src/contrib*)
                 rx='\b\Q'"${pkgname#R-cran-}"'\E_\K\d+(\.\d+)*(-\d+)?(?=\.tar)';;
-            *download.kde.org/stable/applications*|*download.kde.org/stable/frameworks*|*download.kde.org/stable/plasma*)
-                url="${url%%${version%.*}*}"
-                rx='href="\K[\d\.]+(?=/")';;
             *rubygems.org*)
                 url="https://rubygems.org/gems/${pkgname#ruby-}"
                 rx='href="/gems/'${pkgname#ruby-}'/versions/\K[\d\.]*(?=")' ;;