emerge-delta-webrsync: improve date calculations

[portage.git] / misc / emerge-delta-webrsync

diff --git a/misc/emerge-delta-webrsync b/misc/emerge-delta-webrsync
index 874c52719e1e64f255210282f03d86654208704c..e237c7f13dffb57656d11e25e975b27790f34e1f 100755 (executable)
--- a/misc/emerge-delta-webrsync
+++ b/misc/emerge-delta-webrsync
@@ -153,29 +153,56 @@ cleanse_state_dir() {
        [[ ${STATE_DIR:-/} != '/' ]] && rm -f "${STATE_DIR}"/* &> /dev/null
 }
 
+get_utc_date_in_seconds() {
+       date -u +"%s"
+}
+
+get_date_part() {
+       local utc_time_in_secs="$1"
+       local part="$2"
+
+       if      [[ ${USERLAND} == BSD ]] ; then
+               date -r ${utc_time_in_secs} -u +"${part}"
+       else
+               date -d @${utc_time_in_secs} -u +"${part}"
+       fi
+}
+
+increment_date() {
+       local s="$1" inc="$2"
+       if [[ ${USERLAND} == BSD ]] ; then
+               # Specify zeros for the least significant digits, or else those
+               # digits are inherited from the current system clock time.
+               date -v${inc}d -juf "%Y%m%d%H%M.%S" "${s}0000.00" +"%Y%m%d"
+       else
+               date -d "${s:0:4}-${s:4:2}-${s:6:2} ${inc} day" -u +"%Y%m%d"
+       fi
+}
+
 full_version_attempt() {
        local FILE file_exists
        echo "Fetching most recent snapshot"
+
+       local start_time=$(get_utc_date_in_seconds)
+       local start_hour=$(get_date_part ${start_time} "%H")
+       local snapshot_date=$(get_date_part ${start_time} "%Y%m%d")
+
+       # Daily snapshots are created at 00:45 and are not
+       # available until after 01:00. Don't waste time trying
+       # to fetch a snapshot before it's been created.
+       if [ ${start_hour} -lt 1 ] ; then
+               snapshot_date=$(increment_date ${snapshot_date} -1)
+       fi
+
        declare -i attempts=-1
        while (( $attempts <  40 )) ; do
                unset file_exists
                attempts=$(( attempts + 1 ))
+               snapshot_date=$(increment_date ${snapshot_date} -1)
 
-               #this too, sucks.  it works in the interim though.
-               if [ "$USERLAND" == "BSD" ] || [ "$USERLAND" == "Darwin" ] ; then
-                       daysbefore=$(expr $(date +"%s") - 86400 \* $attempts)
-                       day=$(date -r $daysbefore +"%d")
-                       month=$(date -r $daysbefore +"%m")
-                       year=$(date -r $daysbefore +"%Y")
-               else
-                       day=$(date -d "-$attempts day" +"%d")
-                       month=$(date -d "-$attempts day" +"%m")
-                       year=$(date -d "-$attempts day" +"%Y")
-               fi
-
-               FILE="portage-${year}${month}${day}.tar.bz2"
+               FILE="portage-${snapshot_date}.tar.bz2"
 
-               echo "Attempting to fetch file dated: ${year}${month}${day}"
+               echo "Attempting to fetch file dated: ${snapshot_date}"
                
                got_md5=0
 
@@ -220,7 +247,7 @@ full_version_attempt() {
                                cleanse_state_dir
                                echo
                                echo " *** Completed websync, please now perform a normal rsync if possible."
-                               echo "     Update is current as of YYYYMMDD: ${year}${month}${day}"
+                               echo "     Update is current as of YYYYMMDD: ${snapshot_date}"
                                echo
                                exit 0
                        fi
@@ -418,36 +445,11 @@ base_date="${base_version%.tar.bz2}"
 base_date="${base_date#portage-}"
 # we now have yyyymmdd
 
-unset patch_dates
-if [ "$USERLAND" == "BSD" ] || [ "$USERLAND" == "Darwin" ] ; then
-       daysbefore=$(expr $(date +"%s") - 86400 \* $attempts)
-       day=$(date -r $daysbefore +"%d")
-       month=$(date -r $daysbefore +"%m")
-       year=$(date -r $daysbefore +"%Y")
-else
-       day=$(date -d "-$attempts day" +"%d")
-       month=$(date -d "-$attempts day" +"%m")
-       year=$(date -d "-$attempts day" +"%Y")
-fi
-
-#todays_date="${year}${month}${day}"
-
-next_date() {
-       local year day month
-       year="${1:0:4}"
-       month="${1:4:2}"
-       day="${1:6:2}"
-#      if [[ "${USERLAND}" == "BSD" ]] || [[ "${USERLAND}" == "Darwin" ]]; then
-#      else
-               date -d "$year/$month/$day +1 day" +"%Y%m%d"
-#      fi
-}
-
 patches=''
 echo "fetching patches"
 fetched='asdf'
 while [[ -n ${fetched} ]]; do
-       next_day=$(next_date ${base_date})
+       next_day=$(increment_date ${base_date} +1)
        # if we can't get a *single* patch or md5, even one missing, do full.
        p="snapshot-${base_date}-${next_day}.patch.bz2"
        if [[ ! -e ${p}.md5sum ]] && ! fetch_from_mirrors "/snapshots/deltas/${p}.md5sum" "${p}.md5sum"; then