src/add-ons/kernel/file_systems/ramfs/Query.h

   1 /* Query - query parsing and evaluation
   2  *
   3  * Copyright 2001-2004, Axel Dörfler, axeld@pinc-software.de.
   4  * This file may be used under the terms of the MIT License.
   5  *
   6  * Adjusted by Ingo Weinhold <bonefish@cs.tu-berlin.de> for usage in RAM FS.
   7  */
   8 #ifndef QUERY_H
   9 #define QUERY_H
  10
  11
  12 #include <OS.h>
  13 #include <SupportDefs.h>
  14
  15 #include <util/DoublyLinkedList.h>
  16
  17 #include "Index.h"
  18 #include "Stack.h"
  19 #include "ramfs.h"
  20
  21 class Entry;
  22 class Equation;
  23 class IndexIterator;
  24 class Node;
  25 class Query;
  26 class Term;
  27 class Volume;
  28
  29
  30 #define B_QUERY_NON_INDEXED     0x00000002
  31
  32
  33 // Wraps the RAM FS Index to provide the interface required by the Query
  34 // implementation. At least most of it.
  35 //
  36 // IndexWrapper
  37 class IndexWrapper {
  38 public:
  39         IndexWrapper(Volume *volume);
  40
  41         status_t SetTo(const char *name);
  42         void Unset();
  43
  44         uint32 Type() const;
  45         off_t GetSize() const;
  46         int32 KeySize() const;
  47
  48 private:
  49         friend class IndexIterator;
  50
  51         Volume  *fVolume;
  52         Index   *fIndex;
  53 };
  54
  55 // IndexIterator
  56 class IndexIterator {
  57 public:
  58         IndexIterator(IndexWrapper *indexWrapper);
  59
  60         status_t Find(const uint8 *const key, size_t keyLength);
  61         status_t Rewind();
  62         status_t GetNextEntry(uint8 *buffer, uint16 *keyLength, size_t bufferSize,
  63                                                   Entry **entry);
  64
  65 private:
  66         IndexWrapper            *fIndexWrapper;
  67         IndexEntryIterator      fIterator;
  68         bool                            fInitialized;
  69 };
  70
  71
  72 class Expression {
  73         public:
  74                 Expression(char *expr);
  75                 ~Expression();
  76
  77                 status_t InitCheck();
  78                 const char *Position() const { return fPosition; }
  79                 Term *Root() const { return fTerm; }
  80
  81         protected:
  82                 Term *ParseOr(char **expr);
  83                 Term *ParseAnd(char **expr);
  84                 Term *ParseEquation(char **expr);
  85
  86                 bool IsOperator(char **expr,char op);
  87
  88         private:
  89                 Expression(const Expression &);
  90                 Expression &operator=(const Expression &);
  91                         // no implementation
  92
  93                 char *fPosition;
  94                 Term *fTerm;
  95 };
  96
  97 class Query : public DoublyLinkedListLinkImpl<Query> {
  98         public:
  99                 Query(Volume *volume, Expression *expression, uint32 flags);
 100                 ~Query();
 101
 102                 status_t Rewind();
 103                 status_t GetNextEntry(struct dirent *, size_t size);
 104
 105                 void SetLiveMode(port_id port, int32 token);
 106                 void LiveUpdate(Entry *entry, Node* node, const char *attribute,
 107                         int32 type, const uint8 *oldKey, size_t oldLength,
 108                         const uint8 *newKey, size_t newLength);
 109
 110                 Expression *GetExpression() const { return fExpression; }
 111
 112         private:
 113 //              void SendNotification(Entry* entry)
 114
 115         private:
 116                 Volume                  *fVolume;
 117                 Expression              *fExpression;
 118                 Equation                *fCurrent;
 119                 IndexIterator   *fIterator;
 120                 IndexWrapper    fIndex;
 121                 Stack<Equation *> fStack;
 122
 123                 uint32                  fFlags;
 124                 port_id                 fPort;
 125                 int32                   fToken;
 126                 bool                    fNeedsEntry;
 127 };
 128
 129 #endif  /* QUERY_H */