Be explicit about time locks, drop is_internal_lock()/friend tx.

Author: evoskuil

include/bitcoin/system/chain/input.hpp

@@ -44,7 +44,7 @@ class BC_API input
     typedef std::shared_ptr<const input> cptr;
 
     static bool is_relative_locktime_applied(uint32_t sequence) NOEXCEPT;
-    static bool is_locked(uint32_t sequence, size_t height,
+    static bool is_relative_locked(uint32_t sequence, size_t height,
         uint32_t median_time_past, size_t prevout_height,
         uint32_t prevout_median_time_past) NOEXCEPT;
 
@@ -117,17 +117,14 @@ class BC_API input
     size_t signature_operations(bool bip16, bool bip141) const NOEXCEPT;
 
     /// Requires metadata.height and median_time_past (otherwise returns true).
-    bool is_locked(size_t height, uint32_t median_time_past) const NOEXCEPT;
+    bool is_relative_locked(size_t height,
+        uint32_t median_time_past) const NOEXCEPT;
 
 protected:
     input(const chain::point::cptr& point, const chain::script::cptr& script,
         const chain::witness::cptr& witness, uint32_t sequence,
         bool valid) NOEXCEPT;
 
-    /// Any non-zero relative locktime value locks internally-spent input.
-    friend class transaction;
-    bool is_internal_lock() const NOEXCEPT;
-
 private:
     typedef struct { size_t nominal; size_t witnessed; } sizes;
 

include/bitcoin/system/chain/transaction.hpp

@@ -134,7 +134,7 @@ class BC_API transaction
     bool is_dusty(uint64_t minimum_output_value) const NOEXCEPT;
 
     /// Requires no metadata, true if spend in own block would be locked.
-    bool is_internal_lock(const input& in) const NOEXCEPT;
+    bool is_internally_locked(const input& in) const NOEXCEPT;
 
     /// Assumes coinbase if prevout not populated (returns only legacy sigops).
     size_t signature_operations(bool bip16, bool bip141) const NOEXCEPT;
@@ -204,7 +204,7 @@ class BC_API transaction
     /// Check (requires context).
     /// -----------------------------------------------------------------------
 
-    bool is_non_final(size_t height, uint32_t timestamp,
+    bool is_absolute_locked(size_t height, uint32_t timestamp,
         uint32_t median_time_past, bool bip113) const NOEXCEPT;
 
     /// Accept (requires prevouts).
@@ -220,7 +220,8 @@ class BC_API transaction
     /// -----------------------------------------------------------------------
 
     /// Requires input.metadata.height/median_time_past (prevout confirmation).
-    bool is_locked(size_t height, uint32_t median_time_past) const NOEXCEPT;
+    bool is_relative_locked(size_t height,
+        uint32_t median_time_past) const NOEXCEPT;
 
     /// Requires input.metadata.height (prevout confirmation).
     bool is_immature(size_t height) const NOEXCEPT;

src/chain/input.cpp

@@ -399,7 +399,7 @@ bool input::is_relative_locktime_applied(uint32_t sequence) NOEXCEPT
 }
 
 // static
-bool input::is_locked(uint32_t sequence, size_t height,
+bool input::is_relative_locked(uint32_t sequence, size_t height,
     uint32_t median_time_past, size_t prevout_height,
     uint32_t prevout_median_time_past) NOEXCEPT
 {
@@ -412,29 +412,26 @@ bool input::is_locked(uint32_t sequence, size_t height,
     // BIP68: bit 22 determines if relative lock is time or block based.
     if (get_right(sequence, relative_locktime_time_locked_bit))
     {
+        // BIP68: references to median time past are as defined by bip113.
         // BIP68: change sequence to seconds by shift up by 9 bits (x 512).
         auto time = shift_left(blocks, relative_locktime_seconds_shift_left);
         auto age = floored_subtract(median_time_past, prevout_median_time_past);
         return age < time;
     }
 
+    // BIP68: when the relative lock time is block based, it is interpreted as
+    // a minimum block height constraint over the age of the input.
     const auto age = floored_subtract(height, prevout_height);
     return age < blocks;
 }
 
-bool input::is_locked(size_t height, uint32_t median_time_past) const NOEXCEPT
+bool input::is_relative_locked(size_t height,
+    uint32_t median_time_past) const NOEXCEPT
 {
     // Prevout must be found and height/median_time_past metadata populated.
     ////BC_ASSERT(!is_zero(metadata.height));
-    return is_locked(sequence_, height, median_time_past, metadata.height,
-        metadata.median_time_past);
-}
-
-// protected (tx friend)
-bool input::is_internal_lock() const NOEXCEPT
-{
-    // Internal spends have no relative height/mtp (any metadata values work).
-    return is_locked(metadata.height, metadata.median_time_past);
+    return is_relative_locked(sequence_, height, median_time_past,
+        metadata.height, metadata.median_time_past);
 }
 
 bool input::reserved_hash(hash_digest& out) const NOEXCEPT

src/chain/transaction.cpp

@@ -1047,7 +1047,7 @@ bool transaction::is_invalid_coinbase_size() const NOEXCEPT
 // Accept (contextual).
 // ----------------------------------------------------------------------------
 
-bool transaction::is_non_final(size_t height, uint32_t timestamp,
+bool transaction::is_absolute_locked(size_t height, uint32_t timestamp,
     uint32_t median_time_past, bool bip113) const NOEXCEPT
 {
     // BIP113: comparing the locktime against the median of the past 11 block
@@ -1153,7 +1153,7 @@ bool transaction::is_relative_locktime_applied(bool coinbase, uint32_t version,
         (version >= relative_locktime_min_version);
 }
 
-bool transaction::is_internal_lock(const input& in) const NOEXCEPT
+bool transaction::is_internally_locked(const input& in) const NOEXCEPT
 {
     // BIP68: not applied to the sequence of the input of a coinbase.
     BC_ASSERT(!is_coinbase());
@@ -1162,10 +1162,12 @@ bool transaction::is_internal_lock(const input& in) const NOEXCEPT
     if (version_ < relative_locktime_min_version)
         return false;
 
-    return in.is_internal_lock();
+    // Internal spends have no relative height/mtp (own metadata vs. itself).
+    return in.is_relative_locked(in.metadata.height,
+        in.metadata.median_time_past);
 }
 
-bool transaction::is_locked(size_t height,
+bool transaction::is_relative_locked(size_t height,
     uint32_t median_time_past) const NOEXCEPT
 {
     // BIP68: not applied to the sequence of the input of a coinbase.
@@ -1178,11 +1180,9 @@ bool transaction::is_locked(size_t height,
     // BIP68: references to median time past are as defined by bip113.
     const auto locked = [=](const auto& input) NOEXCEPT
     {
-        return input->is_locked(height, median_time_past);
+        return input->is_relative_locked(height, median_time_past);
     };
 
-    // BIP68: when the relative lock time is block based, it is interpreted as
-    // a minimum block height constraint over the age of the input.
     return std::any_of(inputs_->begin(), inputs_->end(), locked);
 }
 
@@ -1289,8 +1289,8 @@ code transaction::check(const context& ctx) const NOEXCEPT
 {
     const auto bip113 = ctx.is_enabled(bip113_rule);
 
-    if (is_non_final(ctx.height, ctx.timestamp, ctx.median_time_past, bip113))
-        return error::transaction_non_final;
+    if (is_absolute_locked(ctx.height, ctx.timestamp, ctx.median_time_past, bip113))
+        return error::absolute_time_locked;
 
     return error::transaction_success;
 }
@@ -1325,7 +1325,7 @@ code transaction::confirm(const context& ctx) const NOEXCEPT
 
     if (is_coinbase())
         return error::transaction_success;
-    if (bip68 && is_locked(ctx.height, ctx.median_time_past))
+    if (bip68 && is_relative_locked(ctx.height, ctx.median_time_past))
         return error::relative_time_locked;
     if (is_immature(ctx.height))
         return error::coinbase_maturity;