4 files changed, 36 insertions, 12 deletions
diff --git a/app/sql/connection.cc b/app/sql/connection.cc
index 4878e1b..53ab07d 100644
--- a/app/sql/connection.cc
+++ b/app/sql/connection.cc
@@ -224,8 +224,10 @@ scoped_refptr<Connection::StatementRef> Connection::GetUniqueStatement(
   return new StatementRef(this, stmt);
 }
 
-bool Connection::DoesTableExist(const char* table_name) {
-  Statement statement(GetUniqueStatement(
+bool Connection::DoesTableExist(const char* table_name) const {
+  // GetUniqueStatement can't be const since statements may modify the
+  // database, but we know ours doesn't modify it, so the cast is safe.
+  Statement statement(const_cast<Connection*>(this)->GetUniqueStatement(
       "SELECT name FROM sqlite_master "
       "WHERE type='table' AND name=?"));
   if (!statement)
@@ -235,12 +237,14 @@ bool Connection::DoesTableExist(const char* table_name) {
 }
 
 bool Connection::DoesColumnExist(const char* table_name,
-                                 const char* column_name) {
+                                 const char* column_name) const {
   std::string sql("PRAGMA TABLE_INFO(");
   sql.append(table_name);
   sql.append(")");
 
-  Statement statement(GetUniqueStatement(sql.c_str()));
+  // Our SQL is non-mutating, so this cast is OK.
+  Statement statement(const_cast<Connection*>(this)->GetUniqueStatement(
+      sql.c_str()));
   if (!statement)
     return false;
 
@@ -259,6 +263,14 @@ int64 Connection::GetLastInsertRowId() const {
   return sqlite3_last_insert_rowid(db_);
 }
 
+int Connection::GetLastChangeCount() const {
+  if (!db_) {
+    NOTREACHED();
+    return 0;
+  }
+  return sqlite3_changes(db_);
+}
+
 int Connection::GetErrorCode() const {
   if (!db_)
     return SQLITE_ERROR;
diff --git a/app/sql/connection.h b/app/sql/connection.h
index 2bb450a..cd9d213 100644
--- a/app/sql/connection.h
+++ b/app/sql/connection.h
@@ -197,15 +197,20 @@ class Connection {
   // Info querying -------------------------------------------------------------
 
   // Returns true if the given table exists.
-  bool DoesTableExist( const char* table_name);
+  bool DoesTableExist( const char* table_name) const;
 
   // Returns true if a column with the given name exists in the given table.
-  bool DoesColumnExist(const char* table_name, const char* column_name);
+  bool DoesColumnExist(const char* table_name, const char* column_name) const;
 
   // Returns sqlite's internal ID for the last inserted row. Valid only
   // immediately after an insert.
   int64 GetLastInsertRowId() const;
 
+  // Returns sqlite's count of the number of rows modified by the last
+  // statement executed. Will be 0 if no statement has executed or the database
+  // is closed.
+  int GetLastChangeCount() const;
+
   // Errors --------------------------------------------------------------------
 
   // Returns the error code associated with the last sqlite operation.
diff --git a/app/sql/statement.cc b/app/sql/statement.cc
index 0b419ba..f625e86 100644
--- a/app/sql/statement.cc
+++ b/app/sql/statement.cc
@@ -170,7 +170,7 @@ std::string Statement::ColumnString(int col) const {
   return result;
 }
 
-int Statement::ColumnByteLength(int col) {
+int Statement::ColumnByteLength(int col) const {
   if (!is_valid()) {
     NOTREACHED();
     return 0;
@@ -178,7 +178,7 @@ int Statement::ColumnByteLength(int col) {
   return sqlite3_column_bytes(ref_->stmt(), col);
 }
 
-const void* Statement::ColumnBlob(int col) {
+const void* Statement::ColumnBlob(int col) const {
   if (!is_valid()) {
     NOTREACHED();
     return NULL;
@@ -187,7 +187,7 @@ const void* Statement::ColumnBlob(int col) {
   return sqlite3_column_blob(ref_->stmt(), col);
 }
 
-void Statement::ColumnBlobAsVector(int col, std::vector<char>* val) {
+void Statement::ColumnBlobAsVector(int col, std::vector<char>* val) const {
   val->clear();
   if (!is_valid()) {
     NOTREACHED();
@@ -202,6 +202,12 @@ void Statement::ColumnBlobAsVector(int col, std::vector<char>* val) {
   }
 }
 
+void Statement::ColumnBlobAsVector(
+    int col,
+    std::vector<unsigned char>* val) const {
+  ColumnBlobAsVector(col, reinterpret_cast< std::vector<char>* >(val));
+}
+
 int Statement::CheckError(int err) {
   succeeded_ = (err == SQLITE_OK || err == SQLITE_ROW || err == SQLITE_DONE);
 
diff --git a/app/sql/statement.h b/app/sql/statement.h
index 371bc4e..a711ae5 100644
--- a/app/sql/statement.h
+++ b/app/sql/statement.h
@@ -105,9 +105,10 @@ class Statement {
   // When reading a blob, you can get a raw pointer to the underlying data,
   // along with the length, or you can just ask us to copy the blob into a
   // vector. Danger! ColumnBlob may return NULL if there is no data!
-  int ColumnByteLength(int col);
-  const void* ColumnBlob(int col);
-  void ColumnBlobAsVector(int col, std::vector<char>* val);
+  int ColumnByteLength(int col) const;
+  const void* ColumnBlob(int col) const;
+  void ColumnBlobAsVector(int col, std::vector<char>* val) const;
+  void ColumnBlobAsVector(int col, std::vector<unsigned char>* val) const;
 
  private:
   // This is intended to check for serious errors and report them to the