[sql] Complain about statement mutations after stepping has started.

DCHECK if any Bind*() calls occur after Step() has been called.  The
bind cannot be implemented at that point, so most likely the calling
code has an error, such as a forgotted Reset().

Also DCHECK if Run() is called after Run() or Step() without an
intervening Reset().  Such a calling sequence is unlikely to be
intentional, because the results of calling Run() twice aren't
defined.

BUG=309759

Review URL: https://codereview.chromium.org/40733003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231098 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 18 insertions, 0 deletions

diff --git a/sql/statement.cc b/sql/statement.cc
index 67b7334..4f5e17f 100644
--- a/sql/statement.cc
+++ b/sql/statement.cc
@@ -16,11 +16,13 @@ namespace sql {
 // only have to check the ref's validity bit.
 Statement::Statement()
     : ref_(new Connection::StatementRef(NULL, NULL, false)),
+      stepped_(false),
       succeeded_(false) {
 }
 
 Statement::Statement(scoped_refptr<Connection::StatementRef> ref)
     : ref_(ref),
+      stepped_(false),
       succeeded_(false) {
 }
 
@@ -50,10 +52,12 @@ bool Statement::CheckValid() const {
 }
 
 bool Statement::Run() {
+  DCHECK(!stepped_);
   ref_->AssertIOAllowed();
   if (!CheckValid())
     return false;
 
+  stepped_ = true;
   return CheckError(sqlite3_step(ref_->stmt())) == SQLITE_DONE;
 }
 
@@ -62,6 +66,7 @@ bool Statement::Step() {
   if (!CheckValid())
     return false;
 
+  stepped_ = true;
   return CheckError(sqlite3_step(ref_->stmt())) == SQLITE_ROW;
 }
 
@@ -77,6 +82,7 @@ void Statement::Reset(bool clear_bound_vars) {
   }
 
   succeeded_ = false;
+  stepped_ = false;
 }
 
 bool Statement::Succeeded() const {
@@ -87,6 +93,7 @@ bool Statement::Succeeded() const {
 }
 
 bool Statement::BindNull(int col) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -98,6 +105,7 @@ bool Statement::BindBool(int col, bool val) {
 }
 
 bool Statement::BindInt(int col, int val) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -105,6 +113,7 @@ bool Statement::BindInt(int col, int val) {
 }
 
 bool Statement::BindInt64(int col, int64 val) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -112,6 +121,7 @@ bool Statement::BindInt64(int col, int64 val) {
 }
 
 bool Statement::BindDouble(int col, double val) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -119,6 +129,7 @@ bool Statement::BindDouble(int col, double val) {
 }
 
 bool Statement::BindCString(int col, const char* val) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -127,6 +138,7 @@ bool Statement::BindCString(int col, const char* val) {
 }
 
 bool Statement::BindString(int col, const std::string& val) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
@@ -142,6 +154,7 @@ bool Statement::BindString16(int col, const string16& value) {
 }
 
 bool Statement::BindBlob(int col, const void* val, int val_len) {
+  DCHECK(!stepped_);
   if (!is_valid())
     return false;
 
diff --git a/sql/statement.h b/sql/statement.h
index 5fedc53..acf89e7 100644
--- a/sql/statement.h
+++ b/sql/statement.h
@@ -178,6 +178,11 @@ class SQL_EXPORT Statement {
   // guaranteed non-NULL.
   scoped_refptr<Connection::StatementRef> ref_;
 
+  // Set after Step() or Run() are called, reset by Reset().  Used to
+  // prevent accidental calls to API functions which would not work
+  // correctly after stepping has started.
+  bool stepped_;
+
   // See Succeeded() for what this holds.
   bool succeeded_;