/// <summary>
/// split PqsqlCommand.CommandText into an array of sub-statements
/// </summary>
/// <returns></returns>
private IEnumerable <string> ParseStatements()
{
#if CODECONTRACTS
Contract.Ensures(Contract.Result <IEnumerable <string> >() != null);
#endif
IntPtr pstate = IntPtr.Zero;
IntPtr varArray = IntPtr.Zero;
try
{
unsafe
{
int offset = 0;
varArray = Marshal.AllocHGlobal((mParams.Count + 1) * sizeof(sbyte *));
// always write NULL before we continue, so finally clause can clean up properly
// if we get hit by an exception
Marshal.WriteIntPtr(varArray, offset, IntPtr.Zero);
foreach (PqsqlParameter param in mParams)
{
// always write NULL before we continue, so finally clause can clean up properly
// if we get hit by an exception
Marshal.WriteIntPtr(varArray, offset, IntPtr.Zero);
string psqlParamName = param.PsqlParameterName;
// psql-specific: characters allowed in variable names: [A-Za-z\200-\377_0-9]
// we only allow lowercase [a-z0-9_], as PsqlParameter always stores parameter names in lowercase
char invalid = psqlParamName.FirstOrDefault(c => !(c >= 'a' && c <= 'z') && !char.IsDigit(c) && c != '_');
if (invalid != default(char))
{
string msg = string.Format(CultureInfo.InvariantCulture, "Parameter name «{0}» contains invalid character «{1}»", psqlParamName, invalid);
throw new PqsqlException(msg, (int)PqsqlState.SYNTAX_ERROR);
}
// variable names are pure ascii
byte[] paramNameArray = Encoding.ASCII.GetBytes(psqlParamName);
int len = paramNameArray.Length;
// we need a null-terminated variable string
IntPtr varString = Marshal.AllocHGlobal(len + 1);
Marshal.Copy(paramNameArray, 0, varString, len);
Marshal.WriteByte(varString, len, 0);
Marshal.WriteIntPtr(varArray, offset, varString);
offset += sizeof(sbyte *);
}
Marshal.WriteIntPtr(varArray, offset, IntPtr.Zero);
}
// varArray pointers must be valid during parsing
pstate = PqsqlBinaryFormat.pqparse_init(varArray);
// always terminate CommandText with a ; (prevents unnecessary re-parsing)
// we have the following cases:
// 1) "select 1; select 2"
// 2) "select 1; select 2 -- dash-dash comment forces newline for semicolon"
// 3) "select 1; select 2; /* slash-star comment forces unnecessary semicolon */"
// 4) "select 1; select 2 -- dash-dash comment triggers ;"
//
// For (1), (2), (3) we simply add a newline + semicolon. Case (4) is more tricky
// and requires to re-start the parser for another round.
string commands = CommandText.TrimEnd();
if (!commands.EndsWith(";", StringComparison.Ordinal))
{
commands += "\n;";
}
byte[] statementsString = PqsqlUTF8Statement.CreateUTF8Statement(commands);
// add a semicolon-separated list of UTF-8 statements
int parsingState = PqsqlBinaryFormat.pqparse_add_statements(pstate, statementsString);
if (parsingState == -1) // syntax error or missing parameter
{
ParsingError(pstate);
}
else if (parsingState == 1) // incomplete input, continue with current parsing state and force final "\n;"
{
statementsString = PqsqlUTF8Statement.CreateUTF8Statement("\n;");
if (PqsqlBinaryFormat.pqparse_add_statements(pstate, statementsString) != 0)
{
ParsingError(pstate); // syntax error / missing parameter / incomplete input
}
}
uint num = PqsqlBinaryFormat.pqparse_num_statements(pstate);
string[] statements = new string[num];
// the null-terminated array of UTF-8 statement strings
IntPtr sptr = PqsqlBinaryFormat.pqparse_get_statements(pstate);
if (num > 0 && sptr != IntPtr.Zero)
{
unsafe
{
for (int i = 0; i < num; i++)
{
sbyte **stm = (sbyte **)sptr.ToPointer();
if (stm == null || *stm == null)
{
break;
}
// convert UTF-8 to UTF-16
statements[i] = PqsqlUTF8Statement.CreateStringFromUTF8(new IntPtr(*stm));
sptr = IntPtr.Add(sptr, sizeof(sbyte *));
}
}
}
#if CODECONTRACTS
Contract.Assert(statements != null);
Contract.Assert(statements.Length == num);
#endif
return(from statement in statements
where !string.IsNullOrWhiteSpace(statement) && statement != ";"
select statement);
}
finally
{
if (pstate != IntPtr.Zero)
{
PqsqlBinaryFormat.pqparse_destroy(pstate);
}
if (varArray != IntPtr.Zero)
{
unsafe
{
for (int i = mParams.Count - 1; i >= 0; i--)
{
IntPtr varPtr = Marshal.ReadIntPtr(varArray, i * sizeof(sbyte *));
if (varPtr != IntPtr.Zero)
{
Marshal.FreeHGlobal(varPtr);
}
}
}
Marshal.FreeHGlobal(varArray);
}
}
}