feat: add client-side C binding for fetching data source state

libs/client-sdk/include/launchdarkly/client_side/bindings/c/sdk.h

@@ -501,9 +501,23 @@ enum LDDataSourceStatus_State {
      * SDK key will never become valid), or because the SDK client was
      * explicitly shut down.
      */
-    LD_DATASOURCESTATUS_STATE_SHUTDOWN = 4
+    LD_DATASOURCESTATUS_STATE_SHUTDOWN = 4,
+
+    LD_DATASOURCESTATUS_STATE_UNUSED_MAXVALUE =
+        INT32_MAX /* Used to ensure the underlying type is
+                   * at least 32 bits. */
 };
 
+/**
+ * @param state The state to convert to a string.
+ * @param default_if_unknown The default string to return if the state is not
+ * recognized.
+ * @return Returns the name of the given LDDataSourceStatus_State.
+ */
+LD_EXPORT(char const*)
+LDDataSourceStatus_State_Name(enum LDDataSourceStatus_State state,
+                              char const* default_if_unknown);
+
 /**
  * Get an enumerated value representing the overall current state of the data
  * source.

libs/client-sdk/include/launchdarkly/client_side/data_source_status.hpp

@@ -2,6 +2,7 @@
 
 #include <chrono>
 #include <cstddef>
+#include <cstdint>
 #include <functional>
 #include <memory>
 #include <optional>
@@ -15,7 +16,7 @@ namespace launchdarkly::client_side::data_sources {
 /**
  * Enumeration of possible data source states.
  */
-enum class DataSourceState {
+enum class DataSourceState : std::int32_t {
     /**
      * The initial state of the data source when the SDK is being
      * initialized.
@@ -62,15 +63,17 @@ enum class DataSourceState {
      * SDK key will never become valid), or because the SDK client was
      * explicitly shut down.
      */
-    kShutdown = 4,
-
-    // BackgroundDisabled,
-
-    // TODO: A plugin of sorts would likely be required to implement
-    // network availability.
-    // kNetworkUnavailable,
+    kShutdown = 4
 };
 
+/**
+ *
+ * @return Returns the name of the given DataSourceState as a string. If
+ * the enum value is not recognized, the default string value is returned.
+ */
+char const* GetDataSourceStateName(DataSourceState state,
+                                   char const* default_if_unknown);
+
 using DataSourceStatus =
     common::data_sources::DataSourceStatusBase<DataSourceState>;
 

libs/client-sdk/src/bindings/c/sdk.cpp

@@ -352,6 +352,14 @@ LDDataSourceStatus_GetState(LDDataSourceStatus status) {
         TO_DATASOURCESTATUS(status)->State());
 }
 
+LD_EXPORT(char const*)
+LDDataSourceStatus_State_Name(enum LDDataSourceStatus_State state,
+                              char const* default_if_unknown) {
+    return GetDataSourceStateName(
+        static_cast<data_sources::DataSourceStatus::DataSourceState>(state),
+        default_if_unknown);
+}
+
 LD_EXPORT(LDDataSourceStatus_ErrorInfo)
 LDDataSourceStatus_GetLastError(LDDataSourceStatus status) {
     LD_ASSERT_NOT_NULL(status);

libs/client-sdk/src/data_sources/data_source_status.cpp

@@ -4,26 +4,27 @@
 
 namespace launchdarkly::client_side::data_sources {
 
-std::ostream& operator<<(std::ostream& out,
-                         DataSourceStatus::DataSourceState const& state) {
+char const* GetDataSourceStateName(DataSourceState state,
+                                   char const* default_if_unknown) {
     switch (state) {
         case DataSourceStatus::DataSourceState::kInitializing:
-            out << "INITIALIZING";
-            break;
+            return "INITIALIZING";
         case DataSourceStatus::DataSourceState::kValid:
-            out << "VALID";
-            break;
+            return "VALID";
         case DataSourceStatus::DataSourceState::kInterrupted:
-            out << "INTERRUPTED";
-            break;
+            return "INTERRUPTED";
         case DataSourceStatus::DataSourceState::kSetOffline:
-            out << "OFFLINE";
-            break;
+            return "OFFLINE";
         case DataSourceStatus::DataSourceState::kShutdown:
-            out << "SHUTDOWN";
-            break;
+            return "SHUTDOWN";
+        default:
+            return default_if_unknown;
     }
+}
 
+std::ostream& operator<<(std::ostream& out,
+                         DataSourceStatus::DataSourceState const& state) {
+    out << GetDataSourceStateName(state, "UNKNOWN");
     return out;
 }
 

libs/client-sdk/tests/client_c_bindings_test.cpp

@@ -80,8 +80,9 @@ TEST(ClientBindings, RegisterFlagListener) {
 }
 
 void StatusListenerFunction(LDDataSourceStatus status, void* user_data) {
-    EXPECT_EQ(LD_DATASOURCESTATUS_STATE_OFFLINE,
-              LDDataSourceStatus_GetState(status));
+    auto const state = LDDataSourceStatus_GetState(status);
+    EXPECT_EQ(LD_DATASOURCESTATUS_STATE_OFFLINE, state);
+    EXPECT_STREQ("OFFLINE", LDDataSourceStatus_State_Name(state, "unknown"));
 }
 
 // This test registers a listener. It doesn't use the listener, but it
@@ -194,3 +195,24 @@ TEST(ClientBindings, ComplexDataSourceStatus) {
 
     LDDataSourceStatus_ErrorInfo_Free(info);
 }
+
+TEST(ClientBindings, TestDataSourceStatusStateName) {
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(LD_DATASOURCESTATUS_STATE_VALID,
+                                               "unknown"),
+                 "VALID");
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(
+                     LD_DATASOURCESTATUS_STATE_OFFLINE, "unknown"),
+                 "OFFLINE");
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(
+                     LD_DATASOURCESTATUS_STATE_INITIALIZING, "unknown"),
+                 "INITIALIZING");
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(
+                     LD_DATASOURCESTATUS_STATE_SHUTDOWN, "unknown"),
+                 "SHUTDOWN");
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(
+                     LD_DATASOURCESTATUS_STATE_INTERRUPTED, "unknown"),
+                 "INTERRUPTED");
+    ASSERT_STREQ(LDDataSourceStatus_State_Name(
+                     LD_DATASOURCESTATUS_STATE_UNUSED_MAXVALUE, "unknown"),
+                 "unknown");
+}