Method IsChannelRemoval

db/document.go:1088–1129

Determine whether the specified revision was a channel removal, based on doc.Channels. If so, construct the standard document body for a removal notification (_removed=true) Set of channels returned from IsChannelRemoval are "Active" channels and NOT "Removed".

(ctx context.Context, revID string)

// removal notification (_removed=true)
// Set of channels returned from IsChannelRemoval are "Active" channels and NOT "Removed".
func (doc *Document) IsChannelRemoval(ctx context.Context, revID string) (bodyBytes []byte, history Revisions, channels base.Set, isRemoval bool, isDelete bool, err error) {

	removedChannels := make(base.Set)

	// Iterate over the document's channel history, looking for channels that were removed at revID.  If found, also identify whether the removal was a tombstone.
	for channel, removal := range doc.Channels {
		if removal != nil && removal.Rev.RevTreeID == revID {
			removedChannels[channel] = struct{}{}
			if removal.Deleted == true {
				isDelete = true
			}
		}
	}
	// If no matches found, return isRemoval=false
	if len(removedChannels) == 0 {
		return nil, nil, nil, false, false, nil
	}

	activeChannels, ok := doc.channelsForRevTreeID(revID)
	if !ok {
		// can't find rev (it was either an unknown rev, or an old non-leaf revision that we can't determine channels for)
		return nil, nil, nil, false, false, nil
	}

	// Build revision history for revID
	revHistory, err := doc.History.getHistory(revID)
	if err != nil {
		return nil, nil, nil, false, false, err
	}

	// If there's no history (because the revision has been pruned from the rev tree), treat revision history as only the specified rev id.
	if len(revHistory) == 0 {
		revHistory = []string{revID}
	}
	history = encodeRevisions(ctx, doc.ID, revHistory)

	// Construct removal body
	// doc ID and rev ID aren't required to be inserted here, as both of those are available in the request.
	bodyBytes = []byte(RemovedRedactedDocument)

	return bodyBytes, history, activeChannels, true, isDelete, nil
}

// Updates a document's channel/role UserAccessMap with new access settings from an AccessMap.
// Returns an array of the user/role names whose access has changed as a result.