[ios] Added support for filters (NSPredicate)

[ios, macos] cleaned up filters

[ios] added a filter example

[ios] utest filters

[ios, macos] nested predicates

[ios] refactored

[ios] filter -> NSPredicate

[ios] fixed mbgl::Any/AllFilter -> NSPredicate

[ios] translate nested mbgl::NotIn filters

[ios] cleanup and added more utests

[ios] fixed a bug in the None filter conversion and improved utests

[ios, macos] doc

[macos] added missing category

[ios, macos] additional utests

[ios, macos] updated documentation

1 files changed, 107 insertions, 0 deletions

diff --git a/platform/darwin/src/NSPredicate+MGLAdditions.mm b/platform/darwin/src/NSPredicate+MGLAdditions.mm
new file mode 100644
index 0000000000..9c3f9c888c
--- /dev/null
+++ b/platform/darwin/src/NSPredicate+MGLAdditions.mm
@@ -0,0 +1,107 @@
+#import "NSPredicate+MGLAdditions.h"
+
+#import "MGLValueEvaluator.h"
+
+class FilterEvaluator {
+public:
+    
+    NSArray* getPredicates(std::vector<mbgl::style::Filter> filters) {
+        NSMutableArray *predicates = [NSMutableArray arrayWithCapacity:filters.size()];
+        for (auto filter : filters) {
+            [predicates addObject:mbgl::style::Filter::visit(filter, FilterEvaluator())];
+        }
+        return predicates;
+    }
+    
+    NSArray* getValues(std::vector<mbgl::Value> values) {
+        NSMutableArray *array = [NSMutableArray arrayWithCapacity:values.size()];
+        for (auto value : values) {
+            [array addObject:mbgl::Value::visit(value, ValueEvaluator())];
+        }
+        return array;
+    }
+    
+    NSPredicate* operator()(mbgl::style::NullFilter filter) {
+        return nil;
+    }
+    
+    NSPredicate* operator()(mbgl::style::EqualsFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K == %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::NotEqualsFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K != %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::GreaterThanFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K > %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::GreaterThanEqualsFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K >= %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::LessThanFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K < %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::LessThanEqualsFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K <= %@", @(filter.key.c_str()), mbgl::Value::visit(filter.value, ValueEvaluator())];
+    }
+    
+    NSPredicate* operator()(mbgl::style::InFilter filter) {
+        return [NSPredicate predicateWithFormat:@"%K IN %@", @(filter.key.c_str()), getValues(filter.values)];
+    }
+    
+    NSPredicate* operator()(mbgl::style::NotInFilter filter) {
+        return [NSPredicate predicateWithFormat:@"NOT %K IN %@", @(filter.key.c_str()), getValues(filter.values)];
+    }
+    
+    NSPredicate* operator()(mbgl::style::AnyFilter filter) {
+        return [NSCompoundPredicate orPredicateWithSubpredicates:getPredicates(filter.filters)];
+    }
+    
+    NSPredicate* operator()(mbgl::style::AllFilter filter) {
+        return [NSCompoundPredicate andPredicateWithSubpredicates:getPredicates(filter.filters)];
+    }
+    
+    NSPredicate* operator()(mbgl::style::NoneFilter filter) {
+        NSArray *predicates = getPredicates(filter.filters);
+        if (predicates.count > 1) {
+            NSCompoundPredicate *predicate = [NSCompoundPredicate andPredicateWithSubpredicates:predicates];
+            return [NSCompoundPredicate notPredicateWithSubpredicate:predicate];
+        } else {
+            return [NSCompoundPredicate notPredicateWithSubpredicate:predicates.firstObject];
+        }
+    }
+    
+    NSPredicate* operator()(mbgl::style::HasFilter filter) {
+        [NSException raise:@"Unsupported filter type"
+                    format:@"Cannot convert mbgl::style::HasFilter to NSPredicate"];
+        return nil;
+    }
+    
+    NSPredicate* operator()(mbgl::style::NotHasFilter filter) {
+        [NSException raise:@"Unsupported filter type"
+                    format:@"Cannot convert mbgl::style::NotHasFilter to NSPredicate"];
+        return nil;
+    }
+    
+};
+
+@implementation NSPredicate (MGLAdditions)
+
+- (mbgl::style::Filter)mgl_filter
+{
+    [NSException raise:@"Not supported"
+                format:@"NSPredicate doesn't implement ’-mgl_filter’. Try with NSComparisonPredicate or NSCompoundPredicate instead."];
+    return {};
+}
+
++ (instancetype)mgl_predicateWithFilter:(mbgl::style::Filter)filter
+{
+    FilterEvaluator evaluator;
+    return mbgl::style::Filter::visit(filter, evaluator);
+}
+
+@end