3 files changed, 238 insertions, 0 deletions

diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 4b30185f1..6905d2d50 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -38,6 +38,7 @@ set(SRCS
             param_package.cpp
             scm_rev.cpp
             string_util.cpp
+            telemetry.cpp
             thread.cpp
             timer.cpp
             )
@@ -74,6 +75,7 @@ set(HEADERS
             string_util.h
             swap.h
             synchronized_wrapper.h
+            telemetry.h
             thread.h
             thread_queue_list.h
             timer.h
diff --git a/src/common/telemetry.cpp b/src/common/telemetry.cpp
new file mode 100644
index 000000000..bf1f54886
--- /dev/null
+++ b/src/common/telemetry.cpp
@@ -0,0 +1,40 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include "common/telemetry.h"
+
+namespace Telemetry {
+
+void FieldCollection::Accept(VisitorInterface& visitor) const {
+    for (const auto& field : fields) {
+        field.second->Accept(visitor);
+    }
+}
+
+void FieldCollection::AddField(std::unique_ptr<FieldInterface> field) {
+    fields[field->GetName()] = std::move(field);
+}
+
+template <class T>
+void Field<T>::Accept(VisitorInterface& visitor) const {
+    visitor.Visit(*this);
+}
+
+template class Field<bool>;
+template class Field<double>;
+template class Field<float>;
+template class Field<u8>;
+template class Field<u16>;
+template class Field<u32>;
+template class Field<u64>;
+template class Field<s8>;
+template class Field<s16>;
+template class Field<s32>;
+template class Field<s64>;
+template class Field<std::string>;
+template class Field<const char*>;
+template class Field<std::chrono::microseconds>;
+
+} // namespace Telemetry
diff --git a/src/common/telemetry.h b/src/common/telemetry.h
new file mode 100644
index 000000000..dd6bbd759
--- /dev/null
+++ b/src/common/telemetry.h
@@ -0,0 +1,196 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <chrono>
+#include <map>
+#include <memory>
+#include <string>
+#include "common/common_types.h"
+
+namespace Telemetry {
+
+/// Field type, used for grouping fields together in the final submitted telemetry log
+enum class FieldType : u8 {
+    None = 0,     ///< No specified field group
+    App,          ///< Citra application fields (e.g. version, branch, etc.)
+    Session,      ///< Emulated session fields (e.g. title ID, log, etc.)
+    Performance,  ///< Emulated performance (e.g. fps, emulated CPU speed, etc.)
+    UserFeedback, ///< User submitted feedback (e.g. star rating, user notes, etc.)
+    UserConfig,   ///< User configuration fields (e.g. emulated CPU core, renderer, etc.)
+    UserSystem,   ///< User system information (e.g. host CPU type, RAM, etc.)
+};
+
+struct VisitorInterface;
+
+/**
+ * Interface class for telemetry data fields.
+ */
+class FieldInterface : NonCopyable {
+public:
+    virtual ~FieldInterface() = default;
+
+    /**
+     * Accept method for the visitor pattern.
+     * @param visitor Reference to the visitor that will visit this field.
+     */
+    virtual void Accept(VisitorInterface& visitor) const = 0;
+
+    /**
+     * Gets the name of this field.
+     * @returns Name of this field as a string.
+     */
+    virtual const std::string& GetName() const = 0;
+};
+
+/**
+ * Represents a telemetry data field, i.e. a unit of data that gets logged and submitted to our
+ * telemetry web service.
+ */
+template <typename T>
+class Field : public FieldInterface {
+public:
+    Field(FieldType type, std::string name, const T& value)
+        : type(type), name(std::move(name)), value(value) {}
+
+    Field(FieldType type, std::string name, T&& value)
+        : type(type), name(std::move(name)), value(std::move(value)) {}
+
+    Field(const Field& other) : Field(other.type, other.name, other.value) {}
+
+    Field& operator=(const Field& other) {
+        type = other.type;
+        name = other.name;
+        value = other.value;
+        return *this;
+    }
+
+    Field& operator=(Field&& other) {
+        type = other.type;
+        name = std::move(other.name);
+        value = std::move(other.value);
+        return *this;
+    }
+
+    void Accept(VisitorInterface& visitor) const override;
+
+    const std::string& GetName() const override {
+        return name;
+    }
+
+    /**
+     * Returns the type of the field.
+     */
+    FieldType GetType() const {
+        return type;
+    }
+
+    /**
+     * Returns the value of the field.
+     */
+    const T& GetValue() const {
+        return value;
+    }
+
+    inline bool operator==(const Field<T>& other) {
+        return (type == other.type) && (name == other.name) && (value == other.value);
+    }
+
+    inline bool operator!=(const Field<T>& other) {
+        return !(*this == other);
+    }
+
+private:
+    std::string name; ///< Field name, must be unique
+    FieldType type{}; ///< Field type, used for grouping fields together
+    T value;          ///< Field value
+};
+
+/**
+ * Collection of data fields that have been logged.
+ */
+class FieldCollection final : NonCopyable {
+public:
+    FieldCollection() = default;
+
+    /**
+     * Accept method for the visitor pattern, visits each field in the collection.
+     * @param visitor Reference to the visitor that will visit each field.
+     */
+    void Accept(VisitorInterface& visitor) const;
+
+    /**
+     * Creates a new field and adds it to the field collection.
+     * @param type Type of the field to add.
+     * @param name Name of the field to add.
+     * @param value Value for the field to add.
+     */
+    template <typename T>
+    void AddField(FieldType type, const char* name, T value) {
+        return AddField(std::make_unique<Field<T>>(type, name, std::move(value)));
+    }
+
+    /**
+     * Adds a new field to the field collection.
+     * @param field Field to add to the field collection.
+     */
+    void AddField(std::unique_ptr<FieldInterface> field);
+
+private:
+    std::map<std::string, std::unique_ptr<FieldInterface>> fields;
+};
+
+/**
+ * Telemetry fields visitor interface class. A backend to log to a web service should implement
+ * this interface.
+ */
+struct VisitorInterface : NonCopyable {
+    virtual ~VisitorInterface() = default;
+
+    virtual void Visit(const Field<bool>& field) = 0;
+    virtual void Visit(const Field<double>& field) = 0;
+    virtual void Visit(const Field<float>& field) = 0;
+    virtual void Visit(const Field<u8>& field) = 0;
+    virtual void Visit(const Field<u16>& field) = 0;
+    virtual void Visit(const Field<u32>& field) = 0;
+    virtual void Visit(const Field<u64>& field) = 0;
+    virtual void Visit(const Field<s8>& field) = 0;
+    virtual void Visit(const Field<s16>& field) = 0;
+    virtual void Visit(const Field<s32>& field) = 0;
+    virtual void Visit(const Field<s64>& field) = 0;
+    virtual void Visit(const Field<std::string>& field) = 0;
+    virtual void Visit(const Field<const char*>& field) = 0;
+    virtual void Visit(const Field<std::chrono::microseconds>& field) = 0;
+
+    /// Completion method, called once all fields have been visited
+    virtual void Complete() = 0;
+};
+
+/**
+ * Empty implementation of VisitorInterface that drops all fields. Used when a functional
+ * backend implementation is not available.
+ */
+struct NullVisitor : public VisitorInterface {
+    ~NullVisitor() = default;
+
+    void Visit(const Field<bool>& /*field*/) override {}
+    void Visit(const Field<double>& /*field*/) override {}
+    void Visit(const Field<float>& /*field*/) override {}
+    void Visit(const Field<u8>& /*field*/) override {}
+    void Visit(const Field<u16>& /*field*/) override {}
+    void Visit(const Field<u32>& /*field*/) override {}
+    void Visit(const Field<u64>& /*field*/) override {}
+    void Visit(const Field<s8>& /*field*/) override {}
+    void Visit(const Field<s16>& /*field*/) override {}
+    void Visit(const Field<s32>& /*field*/) override {}
+    void Visit(const Field<s64>& /*field*/) override {}
+    void Visit(const Field<std::string>& /*field*/) override {}
+    void Visit(const Field<const char*>& /*field*/) override {}
+    void Visit(const Field<std::chrono::microseconds>& /*field*/) override {}
+
+    void Complete() override {}
+};
+
+} // namespace Telemetry