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| 1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 // A handy type for iterating through query results. | |
| 6 // | |
| 7 // Just define your Traits type with | |
| 8 // | |
| 9 // RowType | |
| 10 // Extract(statement*, RowType); | |
| 11 // | |
| 12 // and then pass an sqlite3_stmt into the constructor for begin, | |
| 13 // and use the no-arg constructor for an end iterator. Ex: | |
| 14 // | |
| 15 // for (RowIterator<SomeTraits> i(statement), end; i != end; ++i) | |
| 16 // ... | |
| 17 | |
| 18 #ifndef CHROME_BROWSER_SYNC_UTIL_ROW_ITERATOR_H_ | |
| 19 #define CHROME_BROWSER_SYNC_UTIL_ROW_ITERATOR_H_ | |
| 20 | |
| 21 #include "base/logging.h" | |
| 22 #include "third_party/sqlite/preprocessed/sqlite3.h" | |
| 23 | |
| 24 template <typename ColumnType, int index = 0> | |
| 25 struct SingleColumnTraits { | |
| 26 typedef ColumnType RowType; | |
| 27 inline void Extract(sqlite3_stmt* statement, ColumnType* x) const { | |
| 28 GetColumn(statement, index, x); | |
| 29 } | |
| 30 }; | |
| 31 | |
| 32 template <typename RowTraits> | |
| 33 class RowIterator : public std::iterator<std::input_iterator_tag, | |
| 34 const typename RowTraits::RowType> { | |
| 35 public: | |
| 36 typedef typename RowTraits::RowType RowType; | |
| 37 // Statement must have been prepared, but not yet stepped: | |
| 38 RowIterator(sqlite3_stmt* statement, RowTraits traits = RowTraits()) { | |
| 39 kernel_ = new Kernel; | |
| 40 kernel_->done = false; | |
| 41 kernel_->refcount = 1; | |
| 42 kernel_->statement = statement; | |
| 43 kernel_->row_traits = traits; | |
| 44 ++(*this); | |
| 45 } | |
| 46 RowIterator() : kernel_(NULL) { } // creates end iterator | |
| 47 | |
| 48 RowIterator(const RowIterator& i) | |
| 49 : kernel_(NULL) { | |
| 50 *this = i; | |
| 51 } | |
| 52 | |
| 53 ~RowIterator() { | |
| 54 if (kernel_ && 0 == --(kernel_->refcount)) { | |
| 55 sqlite3_finalize(kernel_->statement); | |
| 56 delete kernel_; | |
| 57 } | |
| 58 } | |
| 59 | |
| 60 RowIterator& operator = (const RowIterator& i) { | |
| 61 if (kernel_ && (0 == --(kernel_->refcount))) { | |
| 62 sqlite3_finalize(kernel_->statement); | |
| 63 delete kernel_; | |
| 64 } | |
| 65 kernel_ = i.kernel_; | |
| 66 if (kernel_) | |
| 67 kernel_->refcount += 1; | |
| 68 return *this; | |
| 69 } | |
| 70 | |
| 71 RowIterator operator ++(int) { | |
| 72 RowIterator i(*this); | |
| 73 return ++i; | |
| 74 } | |
| 75 | |
| 76 RowIterator& operator ++() { | |
| 77 DCHECK(NULL != kernel_); | |
| 78 if (SQLITE_ROW == sqlite3_step(kernel_->statement)) { | |
| 79 kernel_->row_traits.Extract(kernel_->statement, &kernel_->row); | |
| 80 } else { | |
| 81 kernel_->done = true; | |
| 82 } | |
| 83 return *this; | |
| 84 } | |
| 85 | |
| 86 const RowType& operator *() const { | |
| 87 return *(operator -> ()); | |
| 88 } | |
| 89 | |
| 90 const RowType* operator ->() const { | |
| 91 DCHECK(NULL != kernel_); | |
| 92 DCHECK(!kernel_->done); | |
| 93 return &(kernel_->row); | |
| 94 } | |
| 95 | |
| 96 bool operator == (const RowIterator& i) const { | |
| 97 if (kernel_ == i.kernel_) | |
| 98 return true; | |
| 99 if (NULL == kernel_ && i.kernel_->done) | |
| 100 return true; | |
| 101 if (NULL == i.kernel_ && kernel_->done) | |
| 102 return true; | |
| 103 return false; | |
| 104 } | |
| 105 | |
| 106 bool operator != (const RowIterator& i) const { | |
| 107 return !(*this == i); | |
| 108 } | |
| 109 | |
| 110 protected: | |
| 111 struct Kernel { | |
| 112 int refcount; | |
| 113 bool done; | |
| 114 RowType row; | |
| 115 sqlite3_stmt* statement; | |
| 116 RowTraits row_traits; | |
| 117 }; | |
| 118 | |
| 119 Kernel* kernel_; | |
| 120 }; | |
| 121 | |
| 122 #endif // CHROME_BROWSER_SYNC_UTIL_ROW_ITERATOR_H_ | |
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Chromium Code Reviews
Issue 3020010:
sync: Remove unused row_iterator.h file. (Closed)
Base URL: git://git.chromium.org/chromium.git