Support for MultiPolygon

[pawanrawal]

This change is 

[pawanrawal]

Review status: 0 of 41 files reviewed at latest revision, 4 unresolved discussions, some commit checks failed.

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types/geofilter.go, line 48 at r1 (raw file):

type GeoQueryData struct {
	pt    *s2.Point  // If not nil, the input data was a point
	loops []*s2.Loop // If not nil, the input data was a polygon

Contains, Intersects and Within queries can now take MultiPolygons, so we change loops to be a slice.

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types/geofilter.go, line 225 at r1 (raw file):

// a temporary fix.
// TODO(Ashwin): Improve this to make it more accurate.
func WithinPolygon(g1 *s2.Loop, g2 *s2.Loop) bool {

We don't need this as I added a function which checks whether one loop Contains another.

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types/s2.go, line 32 at r1 (raw file):

// Make s2.Loop implement s2.Region
type loopRegion struct {

Go s2 library added functions to loop for ContainsCell and IntersectsCell, so we don't need these.

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types/s2.go, line 79 at r1 (raw file):

// Contains checks whether loop A contains loop B.
func Contains(a *s2.Loop, b *s2.Loop) bool {

I picked this up from the C++ source code.

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Comments from Reviewable

[manishrjain]

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Reviewed 37 of 41 files at r1, 4 of 4 files at r2.
Review status: all files reviewed at latest revision, 6 unresolved discussions.

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types/geofilter.go, line 245 at r2 (raw file):

// returns true if the geometry represented by g is within the given loop or cap
func (q GeoQueryData) isWithin(g geom.T) bool {
	x.AssertTruef(q.pt != nil || len(q.loops) > 0 || q.cap != nil, "At least a point, loop or cap should be defined.")

100 chars.

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types/geofilter.go, line 305 at r2 (raw file):

			}
			return true
		}

Can add an assert here that it shouldn't reach here.

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Comments from Reviewable

[janardhan1993]

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Reviewed 37 of 41 files at r1, 4 of 4 files at r2.
Review status: all files reviewed at latest revision, 6 unresolved discussions.

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Comments from Reviewable

[pawanrawal]

Merged to master.