1 karl  1.11 //%2006////////////////////////////////////////////////////////////////////////

  2 mike  1.2  //

  3 karl  1.7  // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
  4            // Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
  5            // Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;

  6 karl  1.6  // IBM Corp.; EMC Corporation, The Open Group.

  7 karl  1.7  // Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
  8            // IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.

  9 karl  1.9  // Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
 10            // EMC Corporation; VERITAS Software Corporation; The Open Group.

 11 karl  1.11 // Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
 12            // EMC Corporation; Symantec Corporation; The Open Group.

 13 mike  1.2  //
 14            // Permission is hereby granted, free of charge, to any person obtaining a copy

 15 kumpf 1.4  // of this software and associated documentation files (the "Software"), to
 16            // deal in the Software without restriction, including without limitation the
 17            // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 18 mike  1.2  // sell copies of the Software, and to permit persons to whom the Software is
 19            // furnished to do so, subject to the following conditions:
 20            // 

 21 kumpf 1.4  // THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN

 22 mike  1.2  // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
 23            // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT

 24 kumpf 1.4  // LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 25            // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 26            // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 27 mike  1.2  // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 28            // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 29            //
 30            //==============================================================================
 31            //
 32            //%/////////////////////////////////////////////////////////////////////////////
 33            
 34            #ifndef Pegasus_WQLParser_h
 35            #define Pegasus_WQLParser_h
 36            
 37            #include <Pegasus/Common/Config.h>

 38 kumpf 1.5  #include <Pegasus/Common/ArrayInternal.h>

 39 mike  1.2  #include <Pegasus/WQL/Linkage.h>
 40            #include <Pegasus/WQL/WQLSelectStatement.h>

 41 mike  1.10 #include <Pegasus/Common/Buffer.h>

 42 mike  1.2  
 43            PEGASUS_NAMESPACE_BEGIN
 44            
 45            /** This class is the main interface to the WQL parser used for parsing WQL1
 46                compliant SQL statements.
 47            
 48                Here's an example which parses a SELECT statement:
 49            
 50                <pre>

 51 karl  1.12     const char TEXT[] = "SELECT X,Y FROM MyClass WHERE X > 10 AND Y < 3";

 52 mike  1.2  

 53 karl  1.12     // Note that this array must be null-terminated (sizeof(TEXT) includes
 54                // the null-terminator in the count).

 55 mike  1.2  

 56 karl  1.12     Buffer text(TEXT, sizeof(TEXT));

 57 mike  1.2  

 58 karl  1.12     WQLSelectStatement selectStatement;

 59 mike  1.2  

 60 karl  1.12     WQLParser parser;
 61            
 62                try
 63                {
 64                    parser.parse(text, selectStatement);
 65                }
 66                catch (ParseError&)
 67                {
 68                    ...
 69                }
 70                catch (MissingNullTerminator&)
 71                {
 72                    ...
 73                }

 74 mike  1.2      </pre>
 75            
 76                Note that the text must be NULL terminated or else the MissingNullTerminator
 77                exception is thrown.
 78            
 79                The text is read and the result is left in the selectStatement output
 80                argument.
 81            
 82                At this point you might wish to peek at the contents of the selectStatement.
 83                This may be done by calling WQLSelectStatement::print() like this:
 84            
 85                <pre>

 86 karl  1.12     WQLSelectStatement selectStatement;
 87                ...
 88                selectStatement.print();

 89 mike  1.2      </pre>
 90            
 91                For the above query text, the following is printed:
 92            
 93                <pre>

 94 karl  1.12     WQLSelectStatement
 95                {
 96                    _className: "MyClass"
 97            
 98                    _propertyNames[0]: "X"
 99                    _propertyNames[1]: "Y"
100            
101                    _operations[0]: "WQL_GT"
102                    _operations[1]: "WQL_LT"
103                    _operations[2]: "WQL_AND"
104            
105                    _operands[0]: "PROPERTY_NAME: X"
106                    _operands[1]: "INTEGER_VALUE: 10"
107                    _operands[2]: "PROPERTY_NAME: Y"
108                    _operands[3]: "INTEGER_VALUE: 3"
109                }

110 mike  1.2      </pre>
111            
112                The WQLSelectStatement::evaluateWhereClause() method may be called to
113                determine whether a particular instance (whose properties are made 
114                available to he evaluateWhereClause() by a user implementation of the
115                WQLPropertySource class). This method returns true, if the where clause
116                matches this instance. Here is an example:
117            
118                <pre>

119 karl  1.12     WQLSelectStatement selectStatement;
120                ...
121                WQLPropertySource* propertySource = new MyPropertySource(...);
122            
123                if (selectStatement.evaluateWhereClause(propertySource))
124                {
125                    // It's a match!
126                }

127 mike  1.2      </pre>
128            
129                The evaluateWhereClause() method calls propertySource->getValue() to
130                obtain values for each of the properties referred to in where clause (X 
131                and Y in the above query example).
132            
133                The implementer of the WQLPropertySource interface must provide the
134                implementation of getValue() to produce values for the target data
135                types. The WQL library makes no assumptions about the nature of the 
136                target data representation. This was done so that this libary could be
137                adapted to multiple data representations.
138            
139                For use with Pegasus CIMInstance objects, a CIMInstancePropertySource
140                class could be developed whose getValue() method fetches values from 
141                a CIMInstance. Here is an example of how it might be used.
142            
143                <pre>

144 karl  1.12     CIMInstancePropertySource* propertySource 
145                    = new CIMInstancePropertySource(...);

146 mike  1.2  

147 karl  1.12     CIMInstance instance;

148 mike  1.2  

149 karl  1.12     while (instance = GetNextInstance(...))
150                {
151                    propertySource->setInstance(currentInstance);
152            
153                    if (selectStatement.evaluateWhereClause(propertySource))
154                    {
155                    // It's a match!
156                    }
157                }

158 mike  1.2      </pre>
159            
160                Of course the numeration of instances is left to the user of WQL.
161            */
162            class PEGASUS_WQL_LINKAGE WQLParser
163            {
164            public:
165            
166                /** Parse the SELECT statement given by the text parameter and initialize

167 karl  1.12     the statement parameter accordingly.

168 mike  1.2  

169 karl  1.12     Please note that this method is not thread safe. It must be guarded 
170                with mutexes by the caller.

171 mike  1.2  

172 karl  1.12     @param text null-terminated C-string which points to SQL statement.
173                @param statement object which holds the compiled version of the SELECT
174                    statement upon return.
175                @exception ParseError if text is not a valid SELECT statement.
176                @exception MissingNullTerminator if text argument is not 
177                    terminated with a null. 

178 mike  1.2      */
179                static void parse(

180 karl  1.12     const char* text,
181                WQLSelectStatement& statement);

182 mike  1.3  
183                /** Version of parse() taking an array of characters.
184                */
185                static void parse(

186 karl  1.12     const Buffer& text,
187                WQLSelectStatement& statement);

188 mike  1.3  
189                /** Version of parse() taking a string.
190                */
191                static void parse(

192 karl  1.12     const String& text,
193                WQLSelectStatement& statement);

194 mike  1.2  
195            private:
196            
197                /** This method cleans up all the strings which were created by LEX and

198 karl  1.12         passed to YACC. These strings cannot be cleaned up by YACC actions
199                    since the actions that clean up certain strings are not always reached
200                    when errors occur.

201 mike  1.2      */
202                static void cleanup();
203            
204                /** Private constructor to avoid user from creating instance of this class.
205                */
206                WQLParser() { }
207            };
208            
209            PEGASUS_NAMESPACE_END
210            
211            #endif /* Pegasus_WQLParser_h */