Make blinded_msgreqs flag tri-state

Can be on, off, or unset.  This allows Session clients to distinguish
between default or explicitly set (and thus avoids edge cases on setting
a default during upgrade).

include/session/config/user_profile.h

@@ -215,7 +215,7 @@ LIBSESSION_EXPORT void user_profile_set_nts_expiry(config_object* conf, int expi
 ///
 /// Declaration:
 /// ```cpp
-/// BOOL user_profile_get_blinded_msgreqs(
+/// INT user_profile_get_blinded_msgreqs(
 ///     [in]    const config_object*    conf
 /// );
 /// ```
@@ -224,18 +224,20 @@ LIBSESSION_EXPORT void user_profile_set_nts_expiry(config_object* conf, int expi
 /// - `conf` -- [in] Pointer to the config object
 ///
 /// Outputs:
-/// - `bool` -- Returns true if blinded message requests are enabled, false otherwise.
-LIBSESSION_EXPORT bool user_profile_get_blinded_msgreqs(const config_object* conf);
+/// - `int` -- Will be -1 if the config does not have the value explicitly set, 0 if the setting is
+///   explicitly disabled, and 1 if the setting is explicitly enabled.
+LIBSESSION_EXPORT int user_profile_get_blinded_msgreqs(const config_object* conf);
 
 /// API: user_profile/user_profile_set_blinded_msgreqs
 ///
-/// Sets whether blinded message requests should be retrieved from SOGS servers.
+/// Sets whether blinded message requests should be retrieved from SOGS servers.  Set to 1 (or any
+/// positive value) to enable; 0 to disable; and -1 to clear the setting.
 ///
 /// Declaration:
 /// ```cpp
 /// VOID user_profile_set_blinded_msgreqs(
 ///     [in]    config_object*      conf,
-///     [in]    bool                enabled
+///     [in]    int                 enabled
 /// );
 /// ```
 ///
@@ -245,7 +247,7 @@ LIBSESSION_EXPORT bool user_profile_get_blinded_msgreqs(const config_object* con
 ///
 /// Outputs:
 /// - `void` -- Returns Nothing
-LIBSESSION_EXPORT void user_profile_set_blinded_msgreqs(config_object* conf, bool enabled);
+LIBSESSION_EXPORT void user_profile_set_blinded_msgreqs(config_object* conf, int enabled);
 
 #ifdef __cplusplus
 }  // extern "C"

include/session/config/user_profile.hpp

@@ -2,6 +2,7 @@
 
 #include <chrono>
 #include <memory>
+#include <optional>
 #include <session/config.hpp>
 
 #include "base.hpp"
@@ -20,7 +21,9 @@ using namespace std::literals;
 /// + - the priority value for the "Note to Self" pseudo-conversation (higher = higher in the
 ///     conversation list).  Omitted when 0.  -1 means hidden.
 /// e - the expiry timer (in seconds) for the "Note to Self" pseudo-conversation.  Omitted when 0.
-/// M - set to 1 if blinded message request retrieval is *disabled*, omitted if enabled.
+/// M - set to 1 if blinded message request retrieval is enabled, 0 if retrieval is *disabled*, and
+///     omitted if the setting has not been explicitly set (or has been explicitly cleared for some
+///     reason).
 
 class UserProfile final : public ConfigBase {
 
@@ -158,24 +161,32 @@ class UserProfile final : public ConfigBase {
 
     /// API: user_profile/UserProfile::get_blinded_msgreqs
     ///
-    /// Returns true if blinded message requests (i.e. from SOGS servers you are connected to) are
-    /// enabled; if disabled then the Session client should not poll for such incoming message
-    /// requests.
+    /// Accesses whether or not blinded message requests are enabled for the client.  Can have three
+    /// values:
+    ///
+    /// - std::nullopt -- the value has not been given an explicit value so the client should use
+    ///   its default.
+    /// - true -- the value is explicitly enabled (i.e. user wants blinded message requests)
+    /// - false -- the value is explicitly disabled (i.e. user disabled blinded message requests)
     ///
     /// Inputs: None
     ///
     /// Outputs:
-    /// - `bool` - true if blinded message requests are enabled, false otherwise.
-    bool get_blinded_msgreqs() const;
+    /// - `std::optional<bool>` - true/false if blinded message requests are enabled or disabled;
+    ///   `std::nullopt` if the option has not been set either way.
+    std::optional<bool> get_blinded_msgreqs() const;
 
     /// API: user_profile/UserProfile::set_blinded_msgreqs
     ///
     /// Sets whether blinded message requests (i.e. from SOGS servers you are connected to) should
-    /// be enabled or not.
+    /// be enabled or not.  This is typically invoked with either `true` or `false`, but can also be
+    /// called with `std::nullopt` to explicitly clear the value.
     ///
     /// Inputs:
-    /// - `enabled` -- true if blinded message requests should be retrieved, false otherwise.
-    void set_blinded_msgreqs(bool enabled);
+    /// - `enabled` -- true if blinded message requests should be retrieved, false if they should
+    ///   not, and `std::nullopt` to drop the setting from the config (and thus use the client's
+    ///   default).
+    void set_blinded_msgreqs(std::optional<bool> enabled);
 };
 
 }  // namespace session::config

src/config/user_profile.cpp

@@ -127,20 +127,28 @@ LIBSESSION_C_API void user_profile_set_nts_expiry(config_object* conf, int expir
     unbox<UserProfile>(conf)->set_nts_expiry(std::max(0, expiry) * 1s);
 }
 
-void UserProfile::set_blinded_msgreqs(bool enabled) {
-    set_flag(data["M"], !enabled);
+void UserProfile::set_blinded_msgreqs(std::optional<bool> value) {
+    if (!value)
+        data["M"].erase();
+    else
+        data["M"] = static_cast<int>(*value);
 }
 
-bool UserProfile::get_blinded_msgreqs() const {
-    if (auto* M = data["M"].integer(); M && *M > 0)
-        return false;
-    return true;
+std::optional<bool> UserProfile::get_blinded_msgreqs() const {
+    if (auto* M = data["M"].integer(); M)
+        return static_cast<bool>(*M);
+    return std::nullopt;
 }
 
-LIBSESSION_C_API bool user_profile_get_blinded_msgreqs(const config_object* conf) {
-    return unbox<UserProfile>(conf)->get_blinded_msgreqs();
+LIBSESSION_C_API int user_profile_get_blinded_msgreqs(const config_object* conf) {
+    if (auto opt = unbox<UserProfile>(conf)->get_blinded_msgreqs())
+        return static_cast<int>(*opt);
+    return -1;
 }
 
-LIBSESSION_C_API void user_profile_set_blinded_msgreqs(config_object* conf, bool enabled) {
-    unbox<UserProfile>(conf)->set_blinded_msgreqs(enabled);
+LIBSESSION_C_API void user_profile_set_blinded_msgreqs(config_object* conf, int enabled) {
+    std::optional<bool> val;
+    if (enabled >= 0)
+        val = static_cast<bool>(enabled);
+    unbox<UserProfile>(conf)->set_blinded_msgreqs(std::move(val));
 }

tests/test_config_userprofile.cpp

@@ -245,9 +245,13 @@ TEST_CASE("user profile C API", "[config][user_profile][c]") {
     user_profile_set_nts_expiry(conf2, 86400);
     CHECK(user_profile_get_nts_expiry(conf2) == 86400);
 
-    CHECK(user_profile_get_blinded_msgreqs(conf2));
-    user_profile_set_blinded_msgreqs(conf2, false);
-    CHECK_FALSE(user_profile_get_blinded_msgreqs(conf2));
+    CHECK(user_profile_get_blinded_msgreqs(conf2) == -1);
+    user_profile_set_blinded_msgreqs(conf2, 0);
+    CHECK(user_profile_get_blinded_msgreqs(conf2) == 0);
+    user_profile_set_blinded_msgreqs(conf2, -1);
+    CHECK(user_profile_get_blinded_msgreqs(conf2) == -1);
+    user_profile_set_blinded_msgreqs(conf2, 1);
+    CHECK(user_profile_get_blinded_msgreqs(conf2) == 1);
 
     // Both have changes, so push need a push
     CHECK(config_needs_push(conf));
@@ -322,8 +326,8 @@ TEST_CASE("user profile C API", "[config][user_profile][c]") {
     CHECK(user_profile_get_nts_priority(conf2) == 9);
     CHECK(user_profile_get_nts_expiry(conf) == 86400);
     CHECK(user_profile_get_nts_expiry(conf2) == 86400);
-    CHECK_FALSE(user_profile_get_blinded_msgreqs(conf));
-    CHECK_FALSE(user_profile_get_blinded_msgreqs(conf2));
+    CHECK(user_profile_get_blinded_msgreqs(conf) == 1);
+    CHECK(user_profile_get_blinded_msgreqs(conf2) == 1);
 
     config_confirm_pushed(conf, to_push->seqno, "fakehash4");
     config_confirm_pushed(conf2, to_push2->seqno, "fakehash4");