Remove EventValidator (#107)

* [WIP] StartTimeProcessor

* [WIP] DurationProcessor

* [WIP] Remove deprecated TimeFieldsProcessor and split into StartTimeProcessor, EndTimeProcessor, and DurationProcessor

* Add DurationProcessorTest

* Minor changes

* Fix tests

* Remove EventValidator and integrate its functionality into RecurrenceFieldsProcessor.

* Make sure UNTIL in RRULE is in UTC format

* Update AndroidTimeUtils RDATE/EXDATE documentation

* Remove unnecessary UTC conversion for DATE-TIME UNTIL values

Author: rfc2822

lib/src/main/kotlin/at/bitfire/ical4android/EventReader.kt

@@ -8,7 +8,6 @@ package at.bitfire.ical4android
 
 import at.bitfire.ical4android.ICalendar.Companion.CALENDAR_NAME
 import at.bitfire.ical4android.ICalendar.Companion.fromReader
-import at.bitfire.ical4android.validation.EventValidator
 import at.bitfire.synctools.icalendar.CalendarUidSplitter
 import at.bitfire.synctools.icalendar.Css3Color
 import net.fortuna.ical4j.data.ParserException
@@ -52,8 +51,7 @@ class EventReader {
         get() = Logger.getLogger(javaClass.name)
 
     /**
-     * Parses an iCalendar resource, applies [at.bitfire.synctools.icalendar.validation.ICalPreprocessor]
-     * and [EventValidator] to increase compatibility and extracts the VEVENTs.
+     * Parses an iCalendar resource and applies [at.bitfire.synctools.icalendar.validation.ICalPreprocessor].
      *
      * @param from        where the iCalendar is read from
      * @param properties    Known iCalendar properties (like [CALENDAR_NAME]) will be put into this map. Key: property name; value: property value
@@ -105,10 +103,6 @@ class EventReader {
             events += event
         }
 
-        // Try to repair all events after reading the whole iCalendar
-        for (event in events)
-            EventValidator.repair(event)
-
         return events
     }
 

lib/src/main/kotlin/at/bitfire/ical4android/EventWriter.kt

@@ -10,7 +10,6 @@ import at.bitfire.ical4android.ICalendar.Companion.minifyVTimeZone
 import at.bitfire.ical4android.ICalendar.Companion.softValidate
 import at.bitfire.ical4android.ICalendar.Companion.withUserAgents
 import at.bitfire.ical4android.util.DateUtils.isDateTime
-import at.bitfire.ical4android.validation.EventValidator
 import at.bitfire.synctools.exception.InvalidLocalResourceException
 import net.fortuna.ical4j.data.CalendarOutputter
 import net.fortuna.ical4j.model.Calendar
@@ -46,7 +45,7 @@ class EventWriter(
 
 
     /**
-     * Applies error correction over [EventValidator] to an [Event] and generates an iCalendar from it.
+     * Generates an iCalendar from the given [Event].
      *
      * @param event     event to generate iCalendar from
      * @param to        stream that the iCalendar is written to
@@ -58,8 +57,6 @@ class EventWriter(
 
         val dtStart = event.dtStart ?: throw InvalidLocalResourceException("Won't generate event without start time")
 
-        EventValidator.repair(event)     // repair this event before creating the VEVENT
-
         // "main event" (without exceptions)
         val components = ical.components
         val mainEvent = toVEvent(event)

lib/src/main/kotlin/at/bitfire/ical4android/validation/EventValidator.kt

@@ -86,6 +86,8 @@ class EndTimeBuilder: AndroidEntityBuilder {
      * - DTEND and DTSTART are both either DATE or DATE-TIME → original DTEND
      * - DTEND is DATE, DTSTART is DATE-TIME → DTEND is amended to DATE-TIME with time and timezone from DTSTART
      * - DTEND is DATE-TIME, DTSTART is DATE → DTEND is reduced to its date component
+     *
+     * @see at.bitfire.synctools.mapping.calendar.processor.RecurrenceFieldsProcessor.alignUntil
      */
     @VisibleForTesting
     internal fun alignWithDtStart(dtEnd: DtEnd, dtStart: DtStart): DtEnd {

lib/src/main/kotlin/at/bitfire/synctools/mapping/calendar/builder/EndTimeBuilder.kt

@@ -67,7 +67,7 @@ class DurationProcessor(
             val start = startDateTime.toZonedDateTime()
             val end = start + duration
 
-            to.dtEnd = DtEnd(end.toIcal4jDateTime())
+            to.dtEnd = DtEnd(end.toIcal4jDateTime(tzRegistry))
         }
     }
 

lib/src/main/kotlin/at/bitfire/synctools/mapping/calendar/processor/DurationProcessor.kt

@@ -9,13 +9,21 @@ package at.bitfire.synctools.mapping.calendar.processor
 import android.content.Entity
 import android.provider.CalendarContract.Events
 import at.bitfire.ical4android.Event
+import at.bitfire.ical4android.util.TimeApiExtensions.toIcal4jDate
+import at.bitfire.ical4android.util.TimeApiExtensions.toIcal4jDateTime
+import at.bitfire.ical4android.util.TimeApiExtensions.toLocalDate
+import at.bitfire.ical4android.util.TimeApiExtensions.toZonedDateTime
 import at.bitfire.synctools.exception.InvalidLocalResourceException
 import at.bitfire.synctools.util.AndroidTimeUtils
+import net.fortuna.ical4j.model.Date
+import net.fortuna.ical4j.model.DateTime
+import net.fortuna.ical4j.model.Recur
 import net.fortuna.ical4j.model.TimeZoneRegistry
 import net.fortuna.ical4j.model.property.ExDate
 import net.fortuna.ical4j.model.property.ExRule
 import net.fortuna.ical4j.model.property.RDate
 import net.fortuna.ical4j.model.property.RRule
+import java.time.ZonedDateTime
 import java.util.LinkedList
 import java.util.logging.Level
 import java.util.logging.Logger
@@ -33,13 +41,26 @@ class RecurrenceFieldsProcessor(
         val tsStart = values.getAsLong(Events.DTSTART) ?: throw InvalidLocalResourceException("Found event without DTSTART")
         val allDay = (values.getAsInteger(Events.ALL_DAY) ?: 0) != 0
 
+        // provide start date as ical4j Date, if needed
+        val startDate by lazy {
+            AndroidTimeField(
+                timestamp = tsStart,
+                timeZone = values.getAsString(Events.EVENT_TIMEZONE),
+                allDay = allDay,
+                tzRegistry = tzRegistry
+            ).asIcal4jDate()
+        }
+
         // process RRULE field
         val rRules = LinkedList<RRule>()
         values.getAsString(Events.RRULE)?.let { rRuleField ->
             try {
                 for (rule in rRuleField.split(AndroidTimeUtils.RECURRENCE_RULE_SEPARATOR)) {
                     val rule = RRule(rule)
 
+                    // align RRULE UNTIL to DTSTART, if needed
+                    rule.recur = alignUntil(rule.recur, startDate)
+
                     // skip if UNTIL is before event's DTSTART
                     val tsUntil = rule.recur.until?.time
                     if (tsUntil != null && tsUntil <= tsStart) {
@@ -74,6 +95,9 @@ class RecurrenceFieldsProcessor(
                 for (rule in exRuleField.split(AndroidTimeUtils.RECURRENCE_RULE_SEPARATOR)) {
                     val rule = ExRule(null, rule)
 
+                    // align RRULE UNTIL to DTSTART, if needed
+                    rule.recur = alignUntil(rule.recur, startDate)
+
                     // skip if UNTIL is before event's DTSTART
                     val tsUntil = rule.recur.until?.time
                     if (tsUntil != null && tsUntil <= tsStart) {
@@ -109,4 +133,58 @@ class RecurrenceFieldsProcessor(
         }
     }
 
+    /**
+     * Aligns the `UNTIL` of the given recurrence info to the VALUE-type (DATE-TIME/DATE) of [startDate].
+     *
+     * If the aligned `UNTIL` is a DATE-TIME, this method also makes sure that it's specified in UTC format
+     * as required by RFC 5545 3.3.10.
+     *
+     * @param recur         recurrence info whose `UNTIL` shall be aligned
+     * @param startDate     `DTSTART` date to compare with
+     *
+     * @return
+     *
+     * - UNTIL not set → original recur
+     * - UNTIL and DTSTART are both either DATE or DATE-TIME → original recur
+     * - UNTIL is DATE, DTSTART is DATE-TIME → UNTIL is amended to DATE-TIME with time and timezone from DTSTART
+     * - UNTIL is DATE-TIME, DTSTART is DATE → UNTIL is reduced to its date component
+     *
+     * @see at.bitfire.synctools.mapping.calendar.builder.EndTimeBuilder.alignWithDtStart
+     */
+    fun alignUntil(recur: Recur, startDate: Date): Recur {
+        val until: Date? = recur.until
+        if (until == null)
+            return recur
+
+        if (until is DateTime) {
+            // UNTIL is DATE-TIME
+            if (startDate is DateTime) {
+                // DTSTART is DATE-TIME
+                return recur
+            } else {
+                // DTSTART is DATE → only take date part for UNTIL
+                val untilDate = until.toLocalDate()
+                return Recur.Builder(recur)
+                    .until(untilDate.toIcal4jDate())
+                    .build()
+            }
+        } else {
+            // UNTIL is DATE
+            if (startDate is DateTime) {
+                // DTSTART is DATE-TIME → amend UNTIL to UTC DATE-TIME
+                val untilDate = until.toLocalDate()
+                val startTime = startDate.toZonedDateTime()
+                val untilDateWithTime = ZonedDateTime.of(untilDate, startTime.toLocalTime(), startTime.zone)
+                return Recur.Builder(recur)
+                    .until(untilDateWithTime.toIcal4jDateTime(tzRegistry).apply {
+                        isUtc = true
+                    })
+                    .build()
+            } else {
+                // DTSTART is DATE
+                return recur
+            }
+        }
+    }
+
 }

lib/src/main/kotlin/at/bitfire/synctools/mapping/calendar/processor/RecurrenceFieldsProcessor.kt

@@ -144,8 +144,9 @@ object AndroidTimeUtils {
      * Concatenates, if necessary, multiple RDATE/EXDATE lists and converts them to
      * a formatted string which Android calendar provider can process.
      *
-     * Android expects this format: "[TZID;]date1,date2,date3" where date is "yyyymmddThhmmss" (when
-     * TZID is given) or "yyyymmddThhmmssZ". We don't use the TZID format here because then we're limited
+     * Android [expects this format](https://android.googlesource.com/platform/frameworks/opt/calendar/+/68b3632330e7a9a4f9813b7eb671dbfd78c25bcd/src/com/android/calendarcommon2/RecurrenceSet.java#138):
+     * `[TZID;]date1,date2,date3` where date is `yyyymmddThhmmss` (when
+     * TZID is given) or `yyyymmddThhmmssZ`. We don't use the TZID format here because then we're limited
      * to one time-zone, while an iCalendar may contain multiple EXDATE/RDATE lines with different time zones.
      *
      * This method converts the values to the type of [dtStart], if necessary:
@@ -231,7 +232,7 @@ object AndroidTimeUtils {
      * constructed from these values.
      *
      * @param dbStr         formatted string from Android calendar provider (RDATE/EXDATE field)
-     *                      expected format: "[TZID;]date1,date2,date3" where date is "yyyymmddThhmmss[Z]"
+     *                      expected format: `[TZID;]date1,date2,date3` where date is `yyyymmddThhmmss[Z]`
      * @param tzRegistry    time zone registry
      * @param allDay        true: list will contain DATE values; false: list will contain DATE_TIME values
      * @param exclude       this time stamp won't be added to the [DateListProperty]