From cc9320e246afb683bcbe96c7d11273f5a64936dd Mon Sep 17 00:00:00 2001
From: tidwall <joshbaker77@gmail.com>
Date: Fri, 26 Aug 2022 16:23:28 -0700
Subject: [PATCH] Allow for WHERE for on geofence detection

---
 internal/collection/collection.go |  4 +++-
 internal/server/fence.go          | 12 +++++++++++-
 internal/server/scanner.go        | 12 +++++++++---
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/internal/collection/collection.go b/internal/collection/collection.go
index 2bce6966..63c54713 100644
--- a/internal/collection/collection.go
+++ b/internal/collection/collection.go
@@ -191,8 +191,10 @@ func (c *Collection) Set(
 		oldFieldValues = c.fieldValues.get(oldItem.fieldValuesSlot)
 		newFieldValues = oldFieldValues
 		newItem.fieldValuesSlot = oldItem.fieldValuesSlot
+		if len(oldFieldValues) > 0 {
+			oldFieldValues = append([]float64{}, oldFieldValues...)
+		}
 	}
-
 	if fields == nil {
 		if len(values) > 0 {
 			newFieldValues = values
diff --git a/internal/server/fence.go b/internal/server/fence.go
index eb0de389..94bc6de5 100644
--- a/internal/server/fence.go
+++ b/internal/server/fence.go
@@ -105,9 +105,18 @@ func fenceMatch(
 			}
 			detect = "roam"
 		} else {
+			var nocross bool
 			// not using roaming
 			match1 := fenceMatchObject(fence, details.oldObj)
+			if match1 {
+				match1, _, _ = sw.testObject(details.id, details.oldObj, details.oldFields)
+				nocross = !match1
+			}
 			match2 := fenceMatchObject(fence, details.obj)
+			if match2 {
+				match2, _, _ = sw.testObject(details.id, details.obj, details.fields)
+				nocross = !match2
+			}
 			if match1 && match2 {
 				detect = "inside"
 			} else if match1 && !match2 {
@@ -121,7 +130,7 @@ func fenceMatch(
 				if details.command != "fset" {
 					// Maybe the old object and new object create a line that crosses the fence.
 					// Must detect for that possibility.
-					if details.oldObj != nil {
+					if !nocross && details.oldObj != nil {
 						ls := geojson.NewLineString(geometry.NewLine(
 							[]geometry.Point{
 								details.oldObj.Center(),
@@ -176,6 +185,7 @@ func fenceMatch(
 		o:          details.obj,
 		fields:     details.fields,
 		noLock:     true,
+		noTest:     true,
 		distance:   distance,
 		distOutput: fence.distance,
 	})
diff --git a/internal/server/scanner.go b/internal/server/scanner.go
index 7f73a649..839870d8 100644
--- a/internal/server/scanner.go
+++ b/internal/server/scanner.go
@@ -68,6 +68,7 @@ type ScanWriterParams struct {
 	distance        float64
 	distOutput      bool // query or fence requested distance output
 	noLock          bool
+	noTest          bool
 	ignoreGlobMatch bool
 	clip            geojson.Object
 	skipTesting     bool
@@ -373,9 +374,14 @@ func (sw *scanWriter) writeObject(opts ScanWriterParams) bool {
 		sw.mu.Lock()
 		defer sw.mu.Unlock()
 	}
-	ok, keepGoing, _ := sw.testObject(opts.id, opts.o, opts.fields)
-	if !ok {
-		return keepGoing
+
+	keepGoing := true
+	if !opts.noTest {
+		var ok bool
+		ok, keepGoing, _ = sw.testObject(opts.id, opts.o, opts.fields)
+		if !ok {
+			return keepGoing
+		}
 	}
 	sw.count++
 	if sw.output == outputCount {