Source-driven attribution

platform/darwin/src/MGLAttributionInfo.h

@@ -0,0 +1,58 @@
+#import <Foundation/Foundation.h>
+#import <CoreGraphics/CoreGraphics.h>
+#import <CoreLocation/CoreLocation.h>
+
+#import "MGLTypes.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ Information about an attribution statement, usually a copyright or trademark
+ statement, associated with a map source.
+ */
+@interface MGLAttributionInfo : NSObject
+
+/**
+ Parses and returns the attribution infos contained in the given HTML source
+ code string.
+
+ @param htmlString The HTML source code to parse.
+ @param fontSize The default text size in points.
+ @param linkColor The default link color.
+ */
++ (NS_ARRAY_OF(MGLAttributionInfo *) *)attributionInfosFromHTMLString:(NSString *)htmlString fontSize:(CGFloat)fontSize linkColor:(nullable MGLColor *)linkColor;
+
+- (instancetype)initWithTitle:(NSAttributedString *)title URL:(nullable NSURL *)URL;
+
+@property (nonatomic) NSAttributedString *title;
+@property (nonatomic, nullable) NSURL *URL;
+@property (nonatomic, getter=isFeedbackLink) BOOL feedbackLink;
+
+- (nullable NSURL *)feedbackURLAtCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel;
+
+@end
+
+@interface NSMutableArray (MGLAttributionInfoAdditions)
+
+/**
+ Adds the given attribution info object to the receiver as long as it isn’t
+ redundant to any object already in the receiver. Any existing object that is
+ redundant to the given object is replaced by the given object.
+
+ @param info The info object to add to the receiver.
+ @return True if the given info object was added to the receiver.
+ */
+- (void)growArrayByAddingAttributionInfo:(MGLAttributionInfo *)info;
+
+/**
+ Adds each of the given attribution info objects to the receiver as long as it
+ isn’t redundant to any object already in the receiver. Any existing object that
+ is redundant to the given object is replaced by the given object.
+
+ @param infos An array of info objects to add to the receiver.
+ */
+- (void)growArrayByAddingAttributionInfosFromArray:(NS_ARRAY_OF(MGLAttributionInfo *) *)infos;
+
+@end
+
+NS_ASSUME_NONNULL_END

platform/darwin/src/MGLAttributionInfo.mm

@@ -0,0 +1,178 @@
+#import "MGLAttributionInfo.h"
+
+#if TARGET_OS_IPHONE
+    #import <UIKit/UIKit.h>
+#else
+    #import <Cocoa/Cocoa.h>
+#endif
+
+#import "MGLMapCamera.h"
+#import "NSString+MGLAdditions.h"
+
+#include <string>
+
+@implementation MGLAttributionInfo
+
++ (NS_ARRAY_OF(MGLAttributionInfo *) *)attributionInfosFromHTMLString:(NSString *)htmlString fontSize:(CGFloat)fontSize linkColor:(nullable MGLColor *)linkColor {
+    NSDictionary *options = @{
+        NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
+        NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding),
+    };
+    // Apply a bogus, easily detectable style rule to any feedback link, since
+    // NSAttributedString doesn’t preserve the class attribute.
+    NSMutableString *css = [NSMutableString stringWithString:
+                            @".mapbox-improve-map { -webkit-text-stroke-width: 1000px; }"];
+    if (fontSize) {
+        [css appendFormat:@"html { font-size: %.1fpx; }", fontSize];
+    }
+    if (linkColor) {
+        CGFloat red;
+        CGFloat green;
+        CGFloat blue;
+        CGFloat alpha;
+#if !TARGET_OS_IPHONE
+        linkColor = [linkColor colorUsingColorSpaceName:NSCalibratedRGBColorSpace];
+#endif
+        [linkColor getRed:&red green:&green blue:&blue alpha:&alpha];
+        [css appendFormat:
+         @"a:link { color: rgba(%f%%, %f%%, %f%%, %f); }",
+         red * 100, green * 100, blue * 100, alpha];
+    }
+    NSString *styledHTML = [NSString stringWithFormat:@"<style type='text/css'>%@</style>%@", css, htmlString];
+    NSData *htmlData = [styledHTML dataUsingEncoding:NSUTF8StringEncoding];
+
+#if TARGET_OS_IPHONE
+    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithData:htmlData
+                                                                                          options:options
+                                                                               documentAttributes:nil
+                                                                                            error:NULL];
+#else
+    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithHTML:htmlData
+                                                                                          options:options
+                                                                               documentAttributes:nil];
+#endif
+
+    NSMutableArray *infos = [NSMutableArray array];
+    [attributedString enumerateAttribute:NSLinkAttributeName
+                                 inRange:attributedString.mgl_wholeRange
+                                 options:0
+                              usingBlock:
+    ^(id _Nullable value, NSRange range, BOOL * _Nonnull stop) {
+        NSCAssert(!value || [value isKindOfClass:[NSURL class]], @"If present, URL attribute must be an NSURL.");
+
+        // Detect feedback links by the bogus style rule applied above.
+        NSNumber *strokeWidth = [attributedString attribute:NSStrokeWidthAttributeName
+                                                    atIndex:range.location
+                                             effectiveRange:NULL];
+        BOOL isFeedbackLink = NO;
+        if ([strokeWidth floatValue] > 100) {
+            isFeedbackLink = YES;
+            [attributedString removeAttribute:NSStrokeWidthAttributeName range:range];
+        }
+
+        // Omit whitespace-only strings.
+        NSAttributedString *title = [[attributedString attributedSubstringFromRange:range]
+                                     mgl_attributedStringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
+        if (!title.length) {
+            return;
+        }
+
+        MGLAttributionInfo *info = [[MGLAttributionInfo alloc] initWithTitle:title URL:value];
+        info.feedbackLink = isFeedbackLink;
+        [infos addObject:info];
+    }];
+    return infos;
+}
+
+- (instancetype)initWithTitle:(NSAttributedString *)title URL:(NSURL *)URL {
+    if (self = [super init]) {
+        _title = title;
+        _URL = URL;
+    }
+    return self;
+}
+
+- (nullable NSURL *)feedbackURLAtCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel {
+    if (!self.feedbackLink) {
+        return nil;
+    }
+
+    NSURLComponents *components = [NSURLComponents componentsWithURL:self.URL resolvingAgainstBaseURL:NO];
+    components.fragment = [NSString stringWithFormat:@"/%.5f/%.5f/%i",
+                           centerCoordinate.longitude, centerCoordinate.latitude, (int)round(zoomLevel + 1)];
+    return components.URL;
+}
+
+- (BOOL)isEqual:(id)object {
+    return [object isKindOfClass:[self class]] && [[object title] isEqual:self.title] && [[object URL] isEqual:self.URL];
+}
+
+- (NSUInteger)hash {
+    return self.title.hash + self.URL.hash;
+}
+
+/**
+ Returns whether the given attribution info object overlaps with the receiver by
+ its plain text title.
+
+ @return `NSOrderedAscending` if the given object is a superset of the receiver,
+    `NSOrderedDescending` if it is a subset of the receiver, or `NSOrderedSame`
+    if there is no overlap.
+ */
+- (NSComparisonResult)subsetCompare:(MGLAttributionInfo *)otherInfo {
+    NSString *title = self.title.string;
+    NSString *otherTitle = otherInfo.title.string;
+    if ([title containsString:otherTitle]) {
+        return NSOrderedDescending;
+    }
+    if ([otherTitle containsString:title]) {
+        return NSOrderedAscending;
+    }
+    return NSOrderedSame;
+}
+
+@end
+
+@implementation NSMutableArray (MGLAttributionInfoAdditions)
+
+- (void)growArrayByAddingAttributionInfo:(MGLAttributionInfo *)info {
+    __block BOOL didInsertInfo = NO;
+    __block BOOL shouldAddInfo = YES;
+    [self enumerateObjectsUsingBlock:^(MGLAttributionInfo * _Nonnull existingInfo, NSUInteger idx, BOOL * _Nonnull stop) {
+        switch ([info subsetCompare:existingInfo]) {
+            case NSOrderedDescending:
+                // The existing info object is a subset of the one we’re adding.
+                // Replace the existing object the first time we find a subset;
+                // remove the existing object every time after that.
+                if (didInsertInfo) {
+                    [self removeObjectAtIndex:idx];
+                } else {
+                    [self replaceObjectAtIndex:idx withObject:info];
+                    didInsertInfo = YES;
+                }
+                break;
+
+            case NSOrderedAscending:
+                // The info object we’re adding is a subset of the existing one.
+                // Don’t add the object and stop looking.
+                shouldAddInfo = NO;
+                *stop = YES;
+                break;
+
+            default:
+                break;
+        }
+    }];
+    if (shouldAddInfo && !didInsertInfo) {
+        // No overlapping infos were found, so append the info object.
+        [self addObject:info];
+    }
+}
+
+- (void)growArrayByAddingAttributionInfosFromArray:(NS_ARRAY_OF(MGLAttributionInfo *) *)infos {
+    for (MGLAttributionInfo *info in infos) {
+        [self growArrayByAddingAttributionInfo:info];
+    }
+}
+
+@end

platform/darwin/src/MGLGeoJSONSource.mm

@@ -18,6 +18,8 @@
 
 @interface MGLGeoJSONSource ()
 
+- (instancetype)initWithRawSource:(mbgl::style::GeoJSONSource *)rawSource NS_DESIGNATED_INITIALIZER;
+
 @property (nonatomic, readwrite) NSDictionary *options;
 @property (nonatomic) mbgl::style::GeoJSONSource *rawSource;
 
@@ -60,6 +62,10 @@ - (instancetype)initWithIdentifier:(NSString *)identifier shape:(nullable MGLSha
     return self;
 }
 
+- (instancetype)initWithRawSource:(mbgl::style::GeoJSONSource *)rawSource {
+    return [super initWithRawSource:rawSource];
+}
+
 - (void)addToMapView:(MGLMapView *)mapView
 {
     if (_pendingSource == nullptr) {

platform/darwin/src/MGLGeoJSONSource_Private.h

@@ -1,10 +1,11 @@
 #import "MGLGeoJSONSource.h"
-#import "MGLGeoJSONSource_Private.h"
 
 #include <mbgl/style/sources/geojson_source.hpp>
 
 @interface MGLGeoJSONSource (Private)
 
+- (instancetype)initWithRawSource:(mbgl::style::GeoJSONSource *)rawSource;
+
 - (mbgl::style::GeoJSONOptions)geoJSONOptions;
 
 @end

platform/darwin/src/MGLRasterSource.mm

@@ -1,4 +1,4 @@
-#import "MGLRasterSource.h"
+#import "MGLRasterSource_Private.h"
 
 #import "MGLMapView_Private.h"
 #import "MGLSource_Private.h"
@@ -9,6 +9,8 @@
 
 @interface MGLRasterSource ()
 
+- (instancetype)initWithRawSource:(mbgl::style::RasterSource *)rawSource NS_DESIGNATED_INITIALIZER;
+
 @property (nonatomic) mbgl::style::RasterSource *rawSource;
 
 @end
@@ -39,6 +41,16 @@ - (instancetype)initWithIdentifier:(NSString *)identifier tileSet:(MGLTileSet *)
     return self;
 }
 
+- (instancetype)initWithRawSource:(mbgl::style::RasterSource *)rawSource {
+    if (self = [super initWithRawSource:rawSource]) {
+        if (auto attribution = rawSource->getAttribution()) {
+            _tileSet = [[MGLTileSet alloc] initWithTileURLTemplates:@[]];
+            _tileSet.attribution = @(attribution->c_str());
+        }
+    }
+    return self;
+}
+
 - (void)commonInit
 {
     std::unique_ptr<mbgl::style::RasterSource> source;

platform/darwin/src/MGLRasterSource_Private.h

@@ -0,0 +1,13 @@
+#import "MGLRasterSource.h"
+
+namespace mbgl {
+    namespace style {
+        class RasterSource;
+    }
+}
+
+@interface MGLRasterSource (Private)
+
+- (instancetype)initWithRawSource:(mbgl::style::RasterSource *)rawSource;
+
+@end

platform/darwin/src/MGLSource.mm

@@ -20,6 +20,14 @@ - (instancetype)initWithIdentifier:(NSString *)identifier
     return self;
 }
 
+- (instancetype)initWithRawSource:(mbgl::style::Source *)rawSource {
+    NSString *identifier = @(rawSource->getID().c_str());
+    if (self = [self initWithIdentifier:identifier]) {
+        _rawSource = rawSource;
+    }
+    return self;
+}
+
 - (void)addToMapView:(MGLMapView *)mapView {
     [NSException raise:NSInvalidArgumentException format:
      @"The source %@ cannot be added to the style. "

platform/darwin/src/MGLSource_Private.h

@@ -1,12 +1,20 @@
 #import "MGLSource.h"
 
-#include <mbgl/mbgl.hpp>
-#include <mbgl/style/source.hpp>
+namespace mbgl {
+    namespace style {
+        class Source;
+    }
+}
 
 @class MGLMapView;
 
 @interface MGLSource (Private)
 
+/**
+ Initializes and returns a source with a raw pointer to the backing store.
+ */
+- (instancetype)initWithRawSource:(mbgl::style::Source *)rawSource;
+
 /**
  A raw pointer to the mbgl object, which is always initialized, either to the 
  value returned by `mbgl::Map getSource`, or for independently created objects,