Re: Suggested patches for libpq++/pgdatabase.* - Mailing list pgsql-interfaces

On Mon, 26 Feb 2001, J. T. Vermeulen wrote:

> Suggest the following fixes for a future version.  These include some minor
> changes of interface (ints changed to bools) that should be compatible at the
> source level but incompatible at the linking level, so those may have to be
> skipped or deferred to some more convenient time.
> 
> Other changes: fixed possible portability problem for weird platforms (using 
> memset() to clear pointers); fixed minor memory leak in PrintTuples(), and
> marked PrintTuples() / DisplayTuples() as obsolescent; changed dubious 
> parameter names "string" to "str".

Oh, and made constructor 'explicit' for greater safety.

Here's an updated version of the same patch.  Added changes:- made lots of member functions 'const'- documented
GetIsNull()-updated documentation for interface changes
 


Diffs follow:


--- postgresql-7.0.3/src/interfaces/libpq++/pgdatabase.h    Sun Apr 23 00:39:15 2000
+++ postgresql-7.0.3-jtv/src/interfaces/libpq++/pgdatabase.h    Mon Feb 26 15:06:59 2001
@@ -37,35 +37,37 @@class PgDatabase : public PgConnection {public:  // connect to the database with conninfo
-  PgDatabase(const char* conninfo) : PgConnection(conninfo) {}
+  explicit PgDatabase(const char conninfo[]) : PgConnection(conninfo) {}  ~PgDatabase() {}                // close
connectionand clean up    // query result access
 
-  int Tuples();
-  int CmdTuples(); 
+  int Tuples() const;
+  int CmdTuples() const;   int Fields();
-  const char* FieldName(int field_num);
-  int FieldNum(const char* field_name);
-  Oid FieldType(int field_num);
-  Oid FieldType(const char* field_name);
-  short FieldSize(int field_num);
-  short FieldSize(const char* field_name);
-  const char* GetValue(int tup_num, int field_num);
-  const char* GetValue(int tup_num, const char* field_name);
-  int GetIsNull(int tup_num, int field_num);
-  int GetIsNull(int tup_num, const char* field_name);
-  int GetLength(int tup_num, int field_num);
-  int GetLength(int tup_num, const char* field_name);
-  void DisplayTuples(FILE *out = 0, int fillAlign = 1, 
-    const char* fieldSep = "|",int printHeader = 1, int quiet = 0) ;
-  void PrintTuples(FILE *out = 0, int printAttName = 1, 
-    int terseOutput = 0, int width = 0) ;
+  const char* FieldName(int field_num) const;
+  int FieldNum(const char* field_name) const;
+  Oid FieldType(int field_num) const;
+  Oid FieldType(const char* field_name) const;
+  short FieldSize(int field_num) const;
+  short FieldSize(const char* field_name) const;
+  const char* GetValue(int tup_num, int field_num) const;
+  const char* GetValue(int tup_num, const char* field_name) const;
+  bool GetIsNull(int tup_num, int field_num) const;
+  bool GetIsNull(int tup_num, const char* field_name) const;
+  int GetLength(int tup_num, int field_num) const;
+  int GetLength(int tup_num, const char* field_name) const;
+
+  // OBSOLESCENT (use PQprint()):
+  void DisplayTuples(FILE *out=0, bool fillAlign=true, 
+    const char* fieldSep="|", bool printHeader=true, bool quiet=false) const;
+  void PrintTuples(FILE *out=0, bool printAttName=true, 
+    bool terseOutput=false, bool fillAlign=false) const;  // copy command related access
-  int GetLine(char* string, int length);
-  void PutLine(const char* string);
-  const char* OidStatus();
+  int GetLine(char str[], int length);
+  void PutLine(const char str[]);
+  const char* OidStatus() const;  int EndCopy();    protected:




--- postgresql-7.0.3/src/interfaces/libpq++/pgdatabase.cc    Sat Jan 29 17:58:52 2000
+++ postgresql-7.0.3-jtv/src/interfaces/libpq++/pgdatabase.cc    Mon Feb 26 15:09:59 2001
@@ -18,57 +18,57 @@#include "pgdatabase.h"
-void PgDatabase::DisplayTuples(FILE *out, int fillAlign, 
-                               const char* fieldSep, int printHeader,
-                               int /* quiet */) 
+// OBSOLESCENT (uses PQprint(), which is no longer being maintained)
+void PgDatabase::DisplayTuples(FILE *out, 
+    bool fillAlign, 
+    const char* fieldSep, 
+    bool printHeader,
+    bool /* quiet */) const{    PQprintOpt po;
-    memset(&po,0,sizeof(po));
-
-    po.align = fillAlign;
-    po.fieldSep = (char *)fieldSep;    po.header = printHeader;
+    po.align = fillAlign;
+    po.standard = po.html3 = po.expanded = po.pager = 0;
+    po.fieldSep = const_cast<char *>(fieldSep);
+    po.tableOpt = po.caption = 0;
+    po.fieldName = 0;    PQprint(out,pgResult,&po);}
-
-void PgDatabase::PrintTuples(FILE *out, int printAttName, int terseOutput,
-                             int width)
+// OBSOLESCENT (uses PQprint(), which is no longer being maintained)
+void PgDatabase::PrintTuples(FILE *out, 
+    bool printAttName, 
+    bool terseOutput,
+    bool fillAlign) const{    PQprintOpt po;
-    memset(&po,0,sizeof(po));
-
-    po.align = width;
-
-    if(terseOutput) po.fieldSep = strdup("|");
-    else po.fieldSep = "";
-    po.header = printAttName;
+    po.align = fillAlign;
+    po.standard = po.html3 = po.expanded = po.pager = 0;
+    po.tableOpt = po.caption = 0;
+    po.fieldSep = const_cast<char *>(terseOutput ? "" : "|");
+    po.fieldName = 0;    PQprint(out,pgResult,&po);}
-int PgDatabase::Tuples()
+int PgDatabase::Tuples() const{ return PQntuples(pgResult); }
-int PgDatabase::CmdTuples()
+int PgDatabase::CmdTuples() const{
-char *a;
-
-  a = (char *)PQcmdTuples(pgResult);
-  if(!a[0]) return -1;
-
-return atoi(a);
+const char *a = PQcmdTuples(pgResult);
+return a[0] ? atoi(a) : -1;}
@@ -78,91 +78,91 @@}
-const char* PgDatabase::FieldName(int field_num)
+const char* PgDatabase::FieldName(int field_num) const{ return PQfname(pgResult, field_num); }
-int PgDatabase::FieldNum(const char* field_name)
+int PgDatabase::FieldNum(const char* field_name) const{ return PQfnumber(pgResult, field_name); }
-Oid PgDatabase::FieldType(int field_num)
+Oid PgDatabase::FieldType(int field_num) const{ return PQftype(pgResult, field_num); }
-Oid PgDatabase::FieldType(const char* field_name)
+Oid PgDatabase::FieldType(const char* field_name) const{ return PQftype(pgResult, FieldNum(field_name)); }
-short PgDatabase::FieldSize(int field_num)
+short PgDatabase::FieldSize(int field_num) const{ return PQfsize(pgResult, field_num); }
-short PgDatabase::FieldSize(const char* field_name)
+short PgDatabase::FieldSize(const char* field_name) const{ return PQfsize(pgResult, FieldNum(field_name)); }
-const char* PgDatabase::GetValue(int tup_num, int field_num)
+const char* PgDatabase::GetValue(int tup_num, int field_num) const{ return PQgetvalue(pgResult, tup_num, field_num);
}
-const char* PgDatabase::GetValue(int tup_num, const char* field_name)
+const char* PgDatabase::GetValue(int tup_num, const char* field_name) const{ return PQgetvalue(pgResult, tup_num,
FieldNum(field_name));}
 
-int PgDatabase::GetIsNull(int tup_num, int field_num)
+bool PgDatabase::GetIsNull(int tup_num, int field_num) const{ return PQgetisnull(pgResult, tup_num, field_num); }
-int PgDatabase::GetIsNull(int tup_num, const char* field_name)
+bool PgDatabase::GetIsNull(int tup_num, const char* field_name) const{ return PQgetisnull(pgResult, tup_num,
FieldNum(field_name));}
 
-int PgDatabase::GetLength(int tup_num, int field_num)
+int PgDatabase::GetLength(int tup_num, int field_num) const{ return PQgetlength(pgResult, tup_num, field_num); }
-int PgDatabase::GetLength(int tup_num, const char* field_name)
+int PgDatabase::GetLength(int tup_num, const char* field_name) const{ return PQgetlength(pgResult, tup_num,
FieldNum(field_name));}
 
-int PgDatabase::GetLine(char* string, int length)
+int PgDatabase::GetLine(char str[], int length){ 
-return PQgetline(pgConn, string, length); 
+return PQgetline(pgConn, str, length); }
-void PgDatabase::PutLine(const char* string)
+void PgDatabase::PutLine(const char str[]){ 
-PQputline(pgConn, string); 
+PQputline(pgConn, str); }
-const char* PgDatabase::OidStatus()
+const char* PgDatabase::OidStatus() const{ return PQoidStatus(pgResult); }




--- postgresql-7.0.3/doc/src/sgml/libpq++.sgml    Tue May  2 22:01:51 2000
+++ postgresql-7.0.3-jtv/doc/src/sgml/libpq++.sgml    Mon Feb 26 15:17:14 2001
@@ -354,7 +354,7 @@       <function>Tuples</function>       Returns the number of tuples (instances) in the query
result.       <synopsis>
 
-    int PgDatabase::Tuples()
+    int PgDatabase::Tuples() const       </synopsis>      </para>     </listitem>
@@ -364,7 +364,7 @@              Returns the number of rows affected after an INSERT, UPDATE or DELETE.
Ifthe command was anything else, it returns -1.        <synopsis>
 
-      int PgDatabase::CmdTuples()
+      int PgDatabase::CmdTuples() const       </synopsis>      </para>     </listitem>
@@ -383,7 +383,7 @@       Returns the field (attribute) name associated with the given field index.        Field
indicesstart at 0.        <synopsis>
 
-    const char *PgDatabase::FieldName(int field_num)
+    const char *PgDatabase::FieldName(int field_num) const       </synopsis>      </para>     </listitem>
@@ -393,7 +393,7 @@       PQfnumber Returns the field (attribute) index associated with        the given field name.
   <synopsis>
 
-    int PgDatabase::FieldNum(const char* field_name)
+    int PgDatabase::FieldNum(const char* field_name) const       </synopsis>       -1 is returned if the given name
doesnot match any field.      </para>
 
@@ -405,7 +405,7 @@       integer returned is an internal coding of the type. Field indices       start at 0.
<synopsis>
-    Oid PgDatabase::FieldType(int field_num)
+    Oid PgDatabase::FieldType(int field_num) const       </synopsis>      </para>     </listitem>
@@ -416,7 +416,7 @@       integer returned is an internal coding of the type. Field indices       start at 0.
<synopsis>
-    Oid PgDatabase::FieldType(const char* field_name)
+    Oid PgDatabase::FieldType(const char* field_name) const       </synopsis>      </para>     </listitem>
@@ -426,7 +426,7 @@       Returns the size in bytes of the field associated with the given        field index. Field
indicesstart at 0.        <synopsis>
 
-    short PgDatabase::FieldSize(int field_num)
+    short PgDatabase::FieldSize(int field_num) const       </synopsis>       Returns the space allocated for this
fieldin a database tuple given       the field number. In other words the size of the server's binary 
 
@@ -440,7 +440,7 @@       Returns the size in bytes of the field associated with the given        field index. Field
indicesstart at 0.        <synopsis>
 
-    short PgDatabase::FieldSize(const char *field_name)
+    short PgDatabase::FieldSize(const char *field_name) const       </synopsis>       Returns the space allocated for
thisfield in a database tuple given       the field name. In other words the size of the server's binary 
 
@@ -454,7 +454,7 @@       Returns a single field (attribute) value of one tuple of a PGresult.        Tuple and field
indicesstart at 0.        <synopsis>
 
-    const char *PgDatabase::GetValue(int tup_num, int field_num)
+    const char *PgDatabase::GetValue(int tup_num, int field_num) const       </synopsis>       For most queries, the
valuereturned by GetValue is a null-terminated        ASCII string representation of the attribute value. But if
BinaryTuples()
 
@@ -474,7 +474,7 @@       Returns a single field (attribute) value of one tuple of a PGresult.        Tuple and field
indicesstart at 0.        <synopsis>
 
-    const char *PgDatabase::GetValue(int tup_num, const char *field_name)
+    const char *PgDatabase::GetValue(int tup_num, const char *field_name) const       </synopsis>       For most
queries,the value returned by GetValue is a null-terminated        ASCII string representation of the attribute value.
Butif BinaryTuples() 
 
@@ -490,11 +490,33 @@     </listitem>     <listitem>      <para>
+       <function>GetIsNull</function>
+       Returns whether a field has the null value.
+       <synopsis>
+        bool GetIsNull(int tup_num, int field_num) const
+       </synopsis>
+       Note that GetValue will return the empty string for null fields, not
+       the NULL pointer.
+      </para>
+     </listitem>
+     <listitem>
+      <para>
+       <function>GetIsNull</function>
+       Returns whether a field has the null value.
+       <synopsis>
+        bool GetIsNull(int tup_num, const char* field_name) const
+       </synopsis>
+       Note that GetValue will return the empty string for null fields, not
+       the NULL pointer.
+      </para>
+     </listitem>
+     <listitem>
+      <para>       <function>GetLength</function>       Returns the length of a field (attribute) in bytes. Tuple and
field       indices start at 0.        <synopsis>
 
-    int PgDatabase::GetLength(int tup_num, int field_num)
+    int PgDatabase::GetLength(int tup_num, int field_num) const       </synopsis>       This is the actual data length
forthe particular data value, that        is the size of the object pointed to by GetValue. Note that for
 
@@ -508,7 +530,7 @@       Returns the length of a field (attribute) in bytes. Tuple and field        indices start at
0.       <synopsis>
 
-    int PgDatabase::GetLength(int tup_num, const char* field_name)
+    int PgDatabase::GetLength(int tup_num, const char* field_name) const       </synopsis>       This is the actual
datalength for the particular data value, that        is the size of the object pointed to by GetValue. Note that for
 
@@ -522,8 +544,8 @@       Prints out all the tuples and, optionally, the attribute names to the        specified output
stream.       <synopsis>
 
-    void PgDatabase::DisplayTuples(FILE *out = 0, int fillAlign = 1, 
-    const char* fieldSep = "|",int printHeader = 1, int quiet = 0)
+    void PgDatabase::DisplayTuples(FILE *out = 0, bool fillAlign = true, 
+    const char* fieldSep = "|",bool printHeader = true, bool quiet = false) const       </synopsis>      </para>
</listitem>
@@ -533,8 +555,8 @@       Prints out all the tuples and, optionally, the attribute names to the        specified output
stream.       <synopsis>
 
-    void PgDatabase::PrintTuples(FILE *out = 0, int printAttName = 1, 
-    int terseOutput = 0, int width = 0) 
+    void PgDatabase::PrintTuples(FILE *out = 0, bool printAttName = true, 
+    bool terseOutput = false, bool fillAlign = false)  const       </synopsis>      </para>     </listitem>
@@ -558,7 +580,7 @@      <para>       <function>OidStatus</function>       <synopsis>
-    const char *PgDatabase::OidStatus()
+    const char *PgDatabase::OidStatus() const       </synopsis>      </para>     </listitem>
@@ -612,8 +634,8 @@    to see if any notification data is currently available from the backend.
<function>PgDatabase::Notifies</function>   returns the notification from a list of unhandled notifications from the
 
-    backend. The function eturns NULL if there is no pending notifications from the
-    backend.   
+    backend. The function returns NULL if there is no pending notifications 
+    from the backend.       <function>PgDatabase::Notifies</function>    behaves like the popping of a stack.  Once a
notificationis returned    from <function>PgDatabase::Notifies</function>,
 


Jeroen