acquire proper error messages for .step()

sqlite.js

@@ -225,3 +225,42 @@ Database.prototype.insertMany = function (table, columns, rows, callback) {
   });
 }
 
+
+exports.fromErrorCode = function(code) {
+  switch (code) {
+    case 0: return "SQLITE_OK";
+    case 1: return "SQLITE_ERROR";
+    case 2: return "SQLITE_INTERNAL";
+    case 3: return "SQLITE_PERM";
+    case 4: return "SQLITE_ABORT";
+    case 5: return "SQLITE_BUSY";
+    case 6: return "SQLITE_LOCKED";
+    case 7: return "SQLITE_NOMEM";
+    case 8: return "SQLITE_READONLY";
+    case 9: return "SQLITE_INTERRUPT";
+    case 10: return "SQLITE_IOERR";
+    case 11: return "SQLITE_CORRUPT";
+    case 12: return "SQLITE_NOTFOUND";
+    case 13: return "SQLITE_FULL";
+    case 14: return "SQLITE_CANTOPEN";
+    case 15: return "SQLITE_PROTOCOL";
+    case 16: return "SQLITE_EMPTY";
+    case 17: return "SQLITE_SCHEMA";
+    case 18: return "SQLITE_TOOBIG";
+    case 19: return "SQLITE_CONSTRAINT";
+    case 20: return "SQLITE_MISMATCH";
+    case 21: return "SQLITE_MISUSE";
+    case 22: return "SQLITE_NOLFS";
+    case 23: return "SQLITE_AUTH";
+    case 24: return "SQLITE_FORMAT";
+    case 25: return "SQLITE_RANGE";
+    case 26: return "SQLITE_NOTADB";
+  }
+};
+
+exports.sanitizeError = function(err, data) {
+  err.message = exports.fromErrorCode(err.errno) + ', ' + err.message +
+                ' in query "' + err.query +
+                '" with values ' + JSON.stringify(data, false, 4);
+  return err;
+};

src/statement.cc

@@ -513,8 +513,11 @@ int Statement::EIO_AfterStep(eio_req *req) {
   Local<Value> argv[2];
 
   if (sto->error_) {
-    argv[0] = Exception::Error(
-        String::New(sqlite3_errmsg(db)));
+    Local<Value> e = Exception::Error(sto->error_msg_);
+    Local<Object> obj = e->ToObject();
+    obj->Set(NODE_PSYMBOL("errno"), Integer::New(sto->error_));
+    obj->Set(NODE_PSYMBOL("query"), String::NewSymbol(sqlite3_sql(sto->stmt_)));
+    argv[0] = e;
   }
   else {
     argv[0] = Local<Value>::New(Undefined());
@@ -622,6 +625,7 @@ int Statement::EIO_Step(eio_req *req) {
   sqlite3_stmt *stmt = sto->stmt_;
   assert(stmt);
   int rc;
+  const char *msg;
 
   // check if we have already taken a step immediately after prepare
   if (sto->first_rc_ != -1) {
@@ -633,10 +637,16 @@ int Statement::EIO_Step(eio_req *req) {
     sto->first_rc_ = -1;
   }
   else {
-    rc = req->result = sqlite3_step(stmt);
+    sqlite3* db = sqlite3_db_handle(stmt);
+    sqlite3_mutex* mtx = sqlite3_db_mutex(db);
+    sqlite3_mutex_enter(mtx);
+    rc = sqlite3_step(stmt);
+    if (rc != SQLITE_ROW && rc != SQLITE_DONE) msg = sqlite3_errmsg(db);
+    sqlite3_mutex_leave(mtx);
+    req->result = rc;
   }
 
-  sto->error_ = false;
+  sto->error_ = SQLITE_OK;
 
   if (rc == SQLITE_ROW) {
     // If this pointer is NULL, look up and store the columns names.
@@ -713,7 +723,9 @@ int Statement::EIO_Step(eio_req *req) {
     // nothing to do in this case
   }
   else {
-    sto->error_ = true;
+    HandleScope scope;
+    sto->error_ = rc;
+    sto->error_msg_ = scope.Close(String::NewSymbol(msg));
     sto->cells = NULL;
   }
 

src/statement.h

@@ -104,7 +104,8 @@ class Statement : public EventEmitter {
 
     int  column_count_;
     char **column_names_;
-    bool error_;
+    int error_;
+    Local<String> error_msg_;
 
     int first_rc_;
     int mode_;