[1760] Provide the IteratorContext

The one for providing the "normal" lookups is just slightly modified to
accept another SELECT statement. The SELECT statement has a small hack -
since the table does not contain a sigtype column (because it makes
little sense in the nsec3 namespace), it is replaced with column where
everything equals to 1, to position the rdata column to the proper
position.

src/lib/datasrc/sqlite3_accessor.cc

@@ -54,7 +54,8 @@ enum StatementID {
     LOW_DIFF_ID = 13,
     HIGH_DIFF_ID = 14,
     DIFF_RECS = 15,
-    NUM_STATEMENTS = 16
+    NSEC3 = 16,
+    NUM_STATEMENTS = 17
 };
 
 const char* const text_statements[NUM_STATEMENTS] = {
@@ -103,7 +104,15 @@ const char* const text_statements[NUM_STATEMENTS] = {
     // that the columns match the column IDs passed to the iterator
     "SELECT rrtype, ttl, id, rdata, name FROM diffs "   // DIFF_RECS
         "WHERE zone_id=?1 AND id>=?2 and id<=?3 "
-        "ORDER BY id ASC"
+        "ORDER BY id ASC",
+
+    // Query to get the NSEC3 records
+    //
+    // The "1" in SELECT is for positioning the rdata column to the
+    // expected position, so we can reuse the same code as for other
+    // lookups.
+    "SELECT rdtype, ttl, 1, rdata FROM nsec3 WHERE zone_id=?1 AND "
+        "hash=?2"
 };
 
 struct SQLite3Parameters {
@@ -482,19 +491,46 @@ public:
         bindZoneId(id);
     }
 
+    // What kind of query it is - selection of the statement for DB
+    enum QueryType {
+        QT_ANY, // Directly for a domain
+        QT_SUBDOMAINS, // Subdomains of a given domain
+        QT_NSEC3 // Domain in the NSEC3 namespace (the name is is the hash,
+                 // not the whole name)
+    };
+
     // Construct an iterator for records with a specific name. When constructed
     // this way, the getNext() call will copy all fields except name
     Context(const boost::shared_ptr<const SQLite3Accessor>& accessor, int id,
-            const std::string& name, bool subdomains) :
-        iterator_type_(ITT_NAME),
+            const std::string& name, QueryType qtype) :
+        iterator_type_(qtype == QT_NSEC3 ? ITT_NSEC3 : ITT_NAME),
         accessor_(accessor),
         statement_(NULL),
         name_(name)
     {
+        // Choose the statement text depending on the query type
+        const char* statement(NULL);
+        switch (qtype) {
+            case QT_ANY:
+                statement = text_statements[ANY];
+                break;
+            case QT_SUBDOMAINS:
+                statement = text_statements[ANY_SUB];
+                break;
+            case QT_NSEC3:
+                statement = text_statements[NSEC3];
+                break;
+            default:
+                // Can Not Happen - there isn't any other type of query
+                // and all the calls to the constructor are from this
+                // file. Therefore no way to test it throws :-(.
+                isc_throw(Unexpected,
+                          "Invalid qtype passed - unreachable code branch "
+                          "reached");
+        }
+
         // We create the statement now and then just keep getting data from it
-        statement_ = prepare(accessor->dbparameters_->db_,
-                             subdomains ? text_statements[ANY_SUB] :
-                             text_statements[ANY]);
+        statement_ = prepare(accessor->dbparameters_->db_, statement);
         bindZoneId(id);
         bindName(name_);
     }
@@ -511,7 +547,11 @@ public:
             // For both types, we copy the first four columns
             copyColumn(data, TYPE_COLUMN);
             copyColumn(data, TTL_COLUMN);
-            copyColumn(data, SIGTYPE_COLUMN);
+            // The NSEC3 lookup does not provide the SIGTYPE, it is not
+            // necessary and not contained in the table.
+            if (iterator_type_ != ITT_NSEC3) {
+                copyColumn(data, SIGTYPE_COLUMN);
+            }
             copyColumn(data, RDATA_COLUMN);
             // Only copy Name if we are iterating over every record
             if (iterator_type_ == ITT_ALL) {
@@ -537,7 +577,8 @@ private:
     // See description of getNext() and the constructors
     enum IteratorType {
         ITT_ALL,
-        ITT_NAME
+        ITT_NAME,
+        ITT_NSEC3
     };
 
     void copyColumn(std::string (&data)[COLUMN_COUNT], int column) {
@@ -584,13 +625,15 @@ SQLite3Accessor::getRecords(const std::string& name, int id,
                             bool subdomains) const
 {
     return (IteratorContextPtr(new Context(shared_from_this(), id, name,
-                                           subdomains)));
+                                           subdomains ?
+                                           Context::QT_SUBDOMAINS :
+                                           Context::QT_ANY)));
 }
 
 DatabaseAccessor::IteratorContextPtr
-SQLite3Accessor::getNSEC3Records(const std::string&, int) const {
-    // TODO: Implement
-    isc_throw(NotImplemented, "Not implemented yet, see ticket #1760");
+SQLite3Accessor::getNSEC3Records(const std::string& hash, int id) const {
+    return (IteratorContextPtr(new Context(shared_from_this(), id, hash,
+                                           Context::QT_NSEC3)));
 }
 
 DatabaseAccessor::IteratorContextPtr

src/lib/datasrc/tests/sqlite3_accessor_unittest.cc

@@ -183,9 +183,11 @@ TEST_F(SQLite3AccessorTest, nsec3) {
         context(accessor->getNSEC3Records("1BB7SO0452U1QHL98UISNDD9218GELR5",
                                           zone_info.second));
     // This relies on specific ordering in the DB. Is it OK?
-    checkRR(context, "1BB7SO0452U1QHL98UISNDD9218GELR5", "7200", "NSEC3",
+    // The name field is empty, as well as the sigtype one. This is OK, as
+    // both are not needed and the interface allows it.
+    checkRR(context, "", "7200", "NSEC3",
             "1 0 10 FEEDABEE 4KLSVDE8KH8G95VU68R7AHBE1CPQN38J");
-    checkRR(context, "1BB7SO0452U1QHL98UISNDD9218GELR5", "7200", "RRSIG",
+    checkRR(context, "", "7200", "RRSIG",
             "NSEC3 5 4 7200 20100410172647 20100311172647 63192 "
             "sql2.example.com. gNIVj4T8t51fEU6kOPpvK7HOGBFZGbalN5ZK "
             "mInyrww6UWZsUNdw07ge6/U6HfG+/s61RZ/L is2M6yUWHyXbNbj/"