implement index of partial usernames so search-as-you-type can work as expected with listusernamespartial

src/main.cpp

@@ -1175,6 +1175,8 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
     CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
     std::vector<std::pair<uint256, CDiskTxPos> > vPos;
     vPos.reserve(block.vtx.size()-1);
+    std::vector<std::string> vUsernames;
+    vUsernames.reserve(block.vtx.size()-1);
     for (unsigned int i = 0; i < block.vtx.size(); i++)
     {
         const CTransaction &tx = block.vtx[i];
@@ -1184,6 +1186,7 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
             blockundo.vtxundo.push_back(txundo);
             uint256 txid = SerializeHash(make_pair(tx.GetUsername(),-1));
             vPos.push_back(std::make_pair(txid, pos));
+            vUsernames.push_back(tx.GetUsername());
 
             CDiskTxPos oldPos;
             if( pblocktree->ReadTxIndex(txid, oldPos) && pos != oldPos ) {
@@ -1228,6 +1231,11 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
     if (!pblocktree->WriteTxIndex(vPos))
         return state.Abort(_("Failed to write transaction index"));
 
+    for (size_t i=0; i<vUsernames.size(); i++) {
+        if (!pblocktree->AddNameToPartialNameTree(vUsernames.at(i)))
+            return state.Abort(_("Failed to write partial name index"));
+    }
+
     // add this block to the view's block chain
     assert(view.SetBestBlock(pindex));
 

src/twister.cpp

@@ -5,6 +5,7 @@
 #include "main.h"
 #include "init.h"
 #include "bitcoinrpc.h"
+#include "txdb.h"
 
 using namespace json_spirit;
 using namespace std;
@@ -1695,27 +1696,7 @@ Value listusernamespartial(const Array& params, bool fHelp)
         }
     }
 
-    // now the rest, the entire block chain
+    pblocktree->GetNamesFromPartial(userStartsWith, retStrings, count);
-    for(CBlockIndex* pindex = pindexBest; pindex && retStrings.size() < count; pindex = pindex->pprev ) {
-        CBlock block;
-        if( !ReadBlockFromDisk(block, pindex) )
-            continue;
-
-        BOOST_FOREACH(const CTransaction&tx, block.vtx) {
-            if( !tx.IsSpamMessage() ) {
-                string txUsername = tx.userName.ExtractSmallString();
-                if( (exact_match && userStartsWith.size() != txUsername.size()) ||
-                    userStartsWith.size() > txUsername.size() ) {
-                    continue;
-                }
-                int toCompare = userStartsWith.size();
-                if( memcmp( txUsername.data(), userStartsWith.data(), toCompare ) == 0 )
-                    retStrings.insert( txUsername );
-                if( retStrings.size() >= count )
-                   break;
-            }
-        }
-    }
 
     Array ret;
     BOOST_FOREACH(string username, retStrings) {

src/txdb.cpp

@@ -189,6 +189,51 @@ bool CBlockTreeDB::ReadFlag(const std::string &name, bool &fValue) {
     return true;
 }
 
+bool CBlockTreeDB::WritePartialNameTree(const std::string &partialName, const std::string &nextChars) {
+    return Write(std::make_pair('n', partialName), nextChars);
+}
+
+
+bool CBlockTreeDB::ReadPartialNameTree(const std::string &partialName, std::string &nextChars) {
+    return Read(std::make_pair('n', partialName), nextChars);
+}
+
+bool CBlockTreeDB::AddCharToPartialNameTree(const std::string &partialName, char ch) {
+    std::string nextChars;
+    if (ReadPartialNameTree(partialName, nextChars)) {
+        if (nextChars.find(ch) == string::npos) {
+            nextChars.push_back(ch);
+            return WritePartialNameTree(partialName, nextChars);
+        }
+    } else {
+        return WritePartialNameTree(partialName, std::string(1,ch));
+    }
+    return true;
+}
+
+bool CBlockTreeDB::AddNameToPartialNameTree(const std::string &name) {
+    std::string partial;
+    for (size_t i=0; i<name.size()-1; i++) {
+        partial.push_back(name.at(i));
+        if (!AddCharToPartialNameTree( partial, name.at(i+1) ))
+            return false;
+    }
+    return AddCharToPartialNameTree( name, '.' ); // mark end of name
+}
+
+void CBlockTreeDB::GetNamesFromPartial(const std::string &partial, std::set< std::string > &names, size_t count) {
+    std::string nextChars;
+    if (ReadPartialNameTree(partial, nextChars)) {
+        for(size_t i=0; i<nextChars.size() && names.size()<count; i++) {
+            if (nextChars.at(i) == '.') {
+                names.insert(partial);
+            } else {
+                GetNamesFromPartial(partial+nextChars.substr(i,1), names, count);
+            }
+        }
+    }
+}
+
 bool CBlockTreeDB::LoadBlockIndexGuts()
 {
     leveldb::Iterator *pcursor = NewIterator();

src/txdb.h

@@ -51,6 +51,11 @@ public:
     bool WriteTxIndex(const std::vector<std::pair<uint256, CDiskTxPos> > &list);
     bool WriteFlag(const std::string &name, bool fValue);
     bool ReadFlag(const std::string &name, bool &fValue);
+    bool WritePartialNameTree(const std::string &partialName, const std::string &nextChars);
+    bool ReadPartialNameTree(const std::string &partialName, std::string &nextChars);
+    bool AddCharToPartialNameTree(const std::string &partialName, char ch);
+    bool AddNameToPartialNameTree(const std::string &name);
+    void GetNamesFromPartial(const std::string &partial, std::set< std::string > &names, size_t count);
     bool LoadBlockIndexGuts();
 };