1 files changed, 115 insertions, 0 deletions
diff --git a/uAssets/tools/update-diffpatches.sh b/uAssets/tools/update-diffpatches.sh
new file mode 100755
index 0000000..406598e
--- /dev/null
+++ b/uAssets/tools/update-diffpatches.sh
@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+#
+# This script assumes a linux environment
+
+set -e
+
+# To be executed at the root of CDN repo
+#
+# It's not being hosted at CDN because that
+# repo is also used as a website
+
+REPO_DIR=$1
+if [[ -z $REPO_DIR ]]; then
+    echo "Error: repo directory is not provided, aborting"
+    exit 1
+fi
+
+PATCHES_DIR=$2
+if [[ -z $PATCHES_DIR ]]; then
+    echo "Error: patches directory is not provided, aborting"
+    exit 1
+fi
+
+FILTER_FILES=$3
+if [[ -z $FILTER_FILES ]]; then
+    echo "Error: filter lists are not provided, aborting"
+    exit 1
+fi
+FILTER_FILES=( "$FILTER_FILES" )
+
+PATCH_FILES=( $(ls -1v "$PATCHES_DIR"/*.patch | head -n -1) )
+
+# Keep only the most recent (5-day x 4-per-day) patches
+OBSOLETE_PATCHES=( $(ls -1v "$PATCHES_DIR"/*.patch | head -n -20) )
+for FILE in "${OBSOLETE_PATCHES[@]}"; do
+    echo "Removing obsolete patch $FILE"
+    git rm "$FILE"
+done
+
+NEW_PATCH_FILE=$(mktemp)
+DIFF_FILE=$(mktemp)
+
+for PATCH_FILE in "${PATCH_FILES[@]}"; do
+
+    # Extract tag from patch file name
+    [[ ${PATCH_FILE} =~ ^$PATCHES_DIR/([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)\.patch$ ]] && \
+        PREVIOUS_VERSION=${BASH_REMATCH[1]}
+
+    # This will receive a clone of an old version of the current repo
+    echo "Fetching repo at $PREVIOUS_VERSION version"
+    OLD_REPO=$(mktemp -d)
+    git clone -q --single-branch --branch "$PREVIOUS_VERSION" --depth=1 "https://github.com/$REPO_DIR.git" "$OLD_REPO" 2>/dev/null || true
+
+    # Skip if version doesn't exist
+    if [ -z "$(ls -A "$OLD_REPO" 2>/dev/null)" ]; then
+        continue;
+    fi
+
+    : > "$NEW_PATCH_FILE"
+
+    for FILTER_LIST in ${FILTER_FILES[@]}; do
+
+        if [ ! -f "$OLD_REPO/$FILTER_LIST" ]; then continue; fi
+
+        # Patches are for filter lists supporting differential updates
+        if ! (head "$OLD_REPO/$FILTER_LIST" | grep -q '^! Diff-Path: '); then
+            continue
+        fi
+
+        # Reference:
+        # https://github.com/ameshkov/diffupdates
+
+        # Extract diff name from `! Diff-Path:` field
+        DIFF_NAME=$(grep -m 1 -oP '^! Diff-Path: [^#]+#?\K.*' "$FILTER_LIST")
+        # Fall back to `! Diff-Name:` field if no name found
+        # Remove once `! Diff-Name:` is no longer needed after transition
+        if [[ -z $DIFF_NAME ]]; then
+            DIFF_NAME=$(grep -m 1 -oP '^! Diff-Name: \K.+' "$FILTER_LIST")
+        fi
+
+        # We need a patch name to generate a valid patch
+        if [[ -z $DIFF_NAME ]]; then
+            echo "Info: $FILTER_LIST is missing a patch name, skipping"
+            continue
+        fi
+
+        # Compute the RCS diff between current version and new version
+        diff -n "$OLD_REPO/$FILTER_LIST" "$FILTER_LIST" > "$DIFF_FILE" || true
+
+        FILE_CHECKSUM=$(sha1sum "$FILTER_LIST")
+        FILE_CHECKSUM=${FILE_CHECKSUM:0:10}
+
+        DIFF_LINE_COUNT=$(wc -l < "$DIFF_FILE")
+
+        # Patch header
+        DIFF_HEAD="diff name:$DIFF_NAME lines:$DIFF_LINE_COUNT checksum:$FILE_CHECKSUM"
+        printf "\tAdding diff: %s\n" "$DIFF_HEAD"
+        echo "$DIFF_HEAD" >> "$NEW_PATCH_FILE"
+        # Patch data
+        cat "$DIFF_FILE" >> "$NEW_PATCH_FILE"
+
+    done
+
+    rm -rf "$OLD_REPO"
+
+    # Stage changed patch file
+    mv -f "$NEW_PATCH_FILE" "$PATCH_FILE"
+    ls -l "$PATCH_FILE"
+    echo "Info: Staging ${PATCH_FILE}"
+    git add -u "$PATCH_FILE"
+
+done
+
+rm -f "$DIFF_FILE"
+rm -f "$NEW_PATCH_FILE"