4 files changed, 160 insertions, 0 deletions
diff --git a/Swiften/Base/Tristate.h b/Swiften/Base/Tristate.h
new file mode 100644
index 0000000..edb7444
--- /dev/null
+++ b/Swiften/Base/Tristate.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2015 Isode Limited.
+ * All rights reserved.
+ * See the COPYING file for more information.
+ */
+
+#pragma once
+
+namespace Swift {
+
+enum Tristate {Yes, No, Maybe};
+
+}
diff --git a/Swiften/Disco/FeatureOracle.cpp b/Swiften/Disco/FeatureOracle.cpp
new file mode 100644
index 0000000..4e61aa9
--- /dev/null
+++ b/Swiften/Disco/FeatureOracle.cpp
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2015 Isode Limited.
+ * All rights reserved.
+ * See the COPYING file for more information.
+ */
+
+#include <Swiften/Disco/FeatureOracle.h>
+
+#include <algorithm>
+#include <iterator>
+#include <vector>
+
+#include <Swiften/Base/foreach.h>
+#include <Swiften/Disco/EntityCapsProvider.h>
+#include <Swiften/Elements/Presence.h>
+#include <Swiften/FileTransfer/FileTransferManager.h>
+#include <Swiften/JID/JID.h>
+#include <Swiften/Presence/PresenceOracle.h>
+
+namespace Swift {
+
+FeatureOracle::FeatureOracle(EntityCapsProvider* capsProvider, PresenceOracle* presenceOracle) : capsProvider_(capsProvider), presenceOracle_(presenceOracle) {
+
+}
+
+Tristate FeatureOracle::isFileTransferSupported(const JID& jid) {
+	DiscoInfo::ref discoInfo = getDiscoResultForJID(jid);
+	if (discoInfo) {
+		return FileTransferManager::isSupportedBy(discoInfo) ? Yes : No;
+	}
+	else {
+		return Maybe;
+	}
+}
+
+Tristate FeatureOracle::isMessageReceiptsSupported(const JID& jid) {
+	return isFeatureSupported(jid, DiscoInfo::MessageDeliveryReceiptsFeature);
+}
+
+Tristate FeatureOracle::isMessageCorrectionSupported(const JID& jid) {
+	return isFeatureSupported(jid, DiscoInfo::MessageCorrectionFeature);
+}
+
+DiscoInfo::ref FeatureOracle::getDiscoResultForJID(const JID& jid) {
+	DiscoInfo::ref discoInfo;
+	if (jid.isBare()) {
+		// Calculate the common subset of disco features of all available results and return that.
+		std::vector<Presence::ref> availablePresences =  presenceOracle_->getAllPresence(jid);
+
+		bool commonFeaturesInitialized = false;
+		std::vector<std::string> commonFeatures;
+		foreach(Presence::ref presence, availablePresences) {
+			DiscoInfo::ref presenceDiscoInfo = capsProvider_->getCaps(presence->getFrom());
+			if (presenceDiscoInfo) {
+				std::vector<std::string> features = presenceDiscoInfo->getFeatures();
+				if (!commonFeaturesInitialized) {
+					commonFeatures = features;
+					commonFeaturesInitialized = true;
+				}
+				else {
+					std::vector<std::string> featuresToRemove;
+					foreach(const std::string& feature, commonFeatures) {
+						if (std::find(features.begin(), features.end(), feature) == features.end()) {
+							featuresToRemove.push_back(feature);
+						}
+					}
+					foreach(const std::string& featureToRemove, featuresToRemove) {
+						commonFeatures.erase(std::remove(commonFeatures.begin(), commonFeatures.end(), featureToRemove), commonFeatures.end());
+					}
+				}
+			}
+		}
+		discoInfo = boost::make_shared<DiscoInfo>();
+
+		foreach(const std::string& commonFeature, commonFeatures) {
+			discoInfo->addFeature(commonFeature);
+		}
+	}
+	else {
+		// Return the disco result of the full JID.
+		discoInfo = capsProvider_->getCaps(jid);
+	}
+
+	return discoInfo;
+}
+
+Tristate FeatureOracle::isFeatureSupported(const JID& jid, const std::string& feature) {
+	DiscoInfo::ref discoInfo = getDiscoResultForJID(jid);
+	if (discoInfo) {
+		return discoInfo->hasFeature(feature) ? Yes : No;
+	}
+	else {
+		return Maybe;
+	}
+}
+
+}
+
+
diff --git a/Swiften/Disco/FeatureOracle.h b/Swiften/Disco/FeatureOracle.h
new file mode 100644
index 0000000..d579e5a
--- /dev/null
+++ b/Swiften/Disco/FeatureOracle.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2015 Isode Limited.
+ * All rights reserved.
+ * See the COPYING file for more information.
+ */
+
+#pragma once
+
+#include <Swiften/Base/API.h>
+#include <Swiften/Base/Tristate.h>
+#include <Swiften/Elements/DiscoInfo.h>
+
+namespace Swift {
+
+class EntityCapsProvider;
+class JID;
+class PresenceOracle;
+
+/**
+ * @brief The FeatureOracle class enables direct feature support lookup for client features supported by Swiften.
+ */
+class SWIFTEN_API FeatureOracle {
+	public:
+		FeatureOracle(EntityCapsProvider* capsProvider, PresenceOracle* presenceOracle);
+
+	public:
+		Tristate isFileTransferSupported(const JID& jid);
+		Tristate isMessageReceiptsSupported(const JID& jid);
+		Tristate isMessageCorrectionSupported(const JID& jid);
+
+	private:
+		/**
+		 * @brief getDiscoResultForJID returns a  shared reference to a DiscoInfo representing features supported by the jid.
+		 * @param jid The JID to return the DiscoInfo::ref for.
+		 * @return DiscoResult::ref
+		 */
+		DiscoInfo::ref getDiscoResultForJID(const JID& jid);
+
+		Tristate isFeatureSupported(const JID& jid, const std::string& feature);
+
+	private:
+		EntityCapsProvider* capsProvider_;
+		PresenceOracle* presenceOracle_;
+};
+
+}
+
diff --git a/Swiften/Disco/SConscript b/Swiften/Disco/SConscript
index c821b42..1779e26 100644
--- a/Swiften/Disco/SConscript
+++ b/Swiften/Disco/SConscript
@@ -11,5 +11,6 @@ objects = swiften_env.SwiftenObject([
 			"DiscoInfoResponder.cpp",
 			"JIDDiscoInfoResponder.cpp",
 			"DiscoServiceWalker.cpp",
+			"FeatureOracle.cpp",
 		])
 swiften_env.Append(SWIFTEN_OBJECTS = [objects])