Changes to support the ledger cleaner

* Rework ledger save return values to indicate errors to callers
* Add an extra function to support the ledger cleaner.

src/ripple_app/TODO.md

@@ -12,13 +12,6 @@
 
 ## Peers.cpp
 
-## LedgerMaster.cpp
-
-- Change getLedgerByHash() to not use "all bits zero" to mean
-  "return the current ledger"
-
-- replace uint32 with LedgerIndex and choose appropriate names
-
 ## Beast
 
 - Change Stoppable to not require a constructor with parameters

src/ripple_app/ledger/Ledger.cpp

@@ -538,7 +538,7 @@ uint256 Ledger::getHash ()
     return mHash;
 }
 
-void Ledger::saveValidatedLedger (bool current)
+bool Ledger::saveValidatedLedger (bool current)
 {
     WriteLog (lsTRACE, Ledger) << "saveValidatedLedger " << (current ? "" : "fromAcquire ") << getLedgerSeq ();
     static boost::format deleteLedger ("DELETE FROM Ledgers WHERE LedgerSeq = %u;");
@@ -588,7 +588,7 @@ void Ledger::saveValidatedLedger (bool current)
             StaticScopedLockType sl (sPendingSaveLock, __FILE__, __LINE__);
             sPendingSaves.erase(getLedgerSeq());
         }
-        return;
+        return false;
     }
 
     {
@@ -664,6 +664,7 @@ void Ledger::saveValidatedLedger (bool current)
         StaticScopedLockType sl (sPendingSaveLock, __FILE__, __LINE__);
         sPendingSaves.erase(getLedgerSeq());
     }
+    return true;
 }
 
 #ifndef NO_SQLITE3_PREPARE
@@ -1875,12 +1876,15 @@ uint32 Ledger::roundCloseTime (uint32 closeTime, uint32 closeResolution)
     return closeTime - (closeTime % closeResolution);
 }
 
+/** Save, or arrange to save, a fully-validated ledger
+    Returns false on error
+*/
 bool Ledger::pendSaveValidated (bool isSynchronous, bool isCurrent)
 {
     if (!getApp().getHashRouter ().setFlag (getHash (), SF_SAVED))
     {
         WriteLog (lsDEBUG, Ledger) << "Double pend save for " << getLedgerSeq();
-        return false;
+        return true;
     }
 
     assert (isImmutable ());
@@ -1890,13 +1894,13 @@ bool Ledger::pendSaveValidated (bool isSynchronous, bool isCurrent)
         if (!sPendingSaves.insert(getLedgerSeq()).second)
         {
             WriteLog (lsDEBUG, Ledger) << "Pend save with seq in pending saves " << getLedgerSeq();
-            return false;
+            return true;
         }
     }
 
     if (isSynchronous)
     {
-        saveValidatedLedger(isCurrent);
+        return saveValidatedLedger(isCurrent);
     }
     else if (isCurrent)
     {

src/ripple_app/ledger/Ledger.h

@@ -63,6 +63,12 @@ protected:
 //         class. But then what is the meaning of a Ledger object? Is this
 //         really two classes in one? StoreOfAllLedgers + SingleLedgerObject?
 //
+/** Holds some or all of a ledger.
+    This can hold just the header, a partial set of data, or the entire set
+    of data. It all depends on what is in the corresponding SHAMap entry.
+    Various functions are provided to populate or depopulate the caches that
+    the object holds references to.
+*/
 class Ledger
     : public boost::enable_shared_from_this <Ledger>
     , public LedgerBase
@@ -470,7 +476,7 @@ protected:
     {
         saveValidatedLedger(current);
     }
-    void saveValidatedLedger (bool current);
+    bool saveValidatedLedger (bool current);
 
     void updateFees ();
 

src/ripple_app/ledger/LedgerHistory.cpp

@@ -30,8 +30,8 @@
 // FIXME: Need to clean up ledgers by index at some point
 
 LedgerHistory::LedgerHistory ()
-	: mLedgersByHash ("LedgerCache", CACHED_LEDGER_NUM, CACHED_LEDGER_AGE)
-	, mConsensusValidated ("ConsensusValidated", 64, 300)
+        : mLedgersByHash ("LedgerCache", CACHED_LEDGER_NUM, CACHED_LEDGER_AGE)
+        , mConsensusValidated ("ConsensusValidated", 64, 300)
 {
     ;
 }
@@ -159,6 +159,21 @@ void LedgerHistory::validatedLedger (Ledger::ref ledger)
     }
 }
 
+/** Ensure mLedgersByHash doesn't have the wrong hash for a particular index
+*/
+bool LedgerHistory::fixIndex (LedgerIndex ledgerIndex, LedgerHash const& ledgerHash)
+{
+    TaggedCache::ScopedLockType sl (mLedgersByHash.peekMutex (), __FILE__, __LINE__);
+    std::map<uint32, uint256>::iterator it (mLedgersByIndex.find (ledgerIndex));
+
+    if ((it != mLedgersByIndex.end ()) && (it->second != ledgerHash) )
+    {
+        it->second = ledgerHash;
+        return false;
+    }
+    return true;
+}
+
 void LedgerHistory::tune (int size, int age)
 {
     mLedgersByHash.setTargetSize (size);

src/ripple_app/ledger/LedgerHistory.h

@@ -50,6 +50,8 @@ public:
     void builtLedger (Ledger::ref);
     void validatedLedger (Ledger::ref);
 
+    bool fixIndex(LedgerIndex ledgerIndex, LedgerHash const& ledgerHash);
+
 private:
     TaggedCacheType <LedgerHash, Ledger, UptimeTimerAdapter> mLedgersByHash;
     TaggedCacheType <LedgerIndex, std::pair< LedgerHash, LedgerHash >, UptimeTimerAdapter> mConsensusValidated;

src/ripple_app/ledger/LedgerMaster.cpp

@@ -260,6 +260,11 @@ public:
         checkAccept (lastClosed);
     }
 
+    bool fixIndex (LedgerIndex ledgerIndex, LedgerHash const& ledgerHash)
+    {
+        return mLedgerHistory.fixIndex (ledgerIndex, ledgerHash);
+    }
+
     void storeLedger (Ledger::pointer ledger)
     {
         mLedgerHistory.addLedger (ledger, false);

src/ripple_app/ledger/LedgerMaster.h

@@ -122,6 +122,8 @@ public:
     virtual void newPathRequest () = 0;
     virtual void newOrderBookDB () = 0;
 
+    virtual bool fixIndex (LedgerIndex ledgerIndex, LedgerHash const& ledgerHash) = 0;
+
     static bool shouldAcquire (uint32 currentLedgerID, uint32 ledgerHistory, uint32 targetLedger);
 };
 

src/ripple_app/ledger/TODO.md

@@ -0,0 +1,18 @@
+# ripple_app
+
+## Ledger.cpp
+
+- Move all inlines into the .cpp, make the interface abstract
+
+- Move static database functions into a real class, perhaps LedgerMaster
+
+## LedgerMaster.cpp
+
+- Change getLedgerByHash() to not use "all bits zero" to mean
+  "return the current ledger"
+
+- replace uint32 with LedgerIndex and choose appropriate names
+
+## Beast
+
+- Change Stoppable to not require a constructor with parameters