1 // Copyright 2014 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 #ifndef TOOLS_GN_DEPS_ITERATOR_H_ 6 #define TOOLS_GN_DEPS_ITERATOR_H_ 7 8 #include <stddef.h> 9 10 #include "gn/label_ptr.h" 11 12 // Provides an iterator for iterating over multiple LabelTargetVectors to 13 // make it convenient to iterate over all deps of a target. 14 // 15 // This works by maintaining a simple stack of vectors (since we have a fixed 16 // number of deps types). When the stack is empty, we've reached the end. This 17 // means that the default-constructed iterator == end() for any sequence. 18 class DepsIterator { 19 public: 20 // Creates an empty iterator. 21 DepsIterator(); 22 23 // Iterate over the deps in the given vectors. If passing less than three, 24 // pad with nulls. 25 DepsIterator(const LabelTargetVector* a, 26 const LabelTargetVector* b, 27 const LabelTargetVector* c); 28 29 // Prefix increment operator. This assumes there are more items (i.e. 30 // *this != DepsIterator()). 31 // 32 // For internal use, this function tolerates an initial index equal to the 33 // length of the current vector. In this case, it will advance to the next 34 // one. 35 DepsIterator& operator++(); 36 37 // Comparison for STL-based loops. 38 bool operator!=(const DepsIterator& other) const { 39 return current_index_ != other.current_index_ || 40 vect_stack_[0] != other.vect_stack_[0] || 41 vect_stack_[1] != other.vect_stack_[1] || 42 vect_stack_[2] != other.vect_stack_[2]; 43 } 44 45 // Dereference operator for STL-compatible iterators. 46 const LabelTargetPair& operator*() const { 47 DCHECK_LT(current_index_, vect_stack_[0]->size()); 48 return (*vect_stack_[0])[current_index_]; 49 } 50 51 private: 52 const LabelTargetVector* vect_stack_[3]; 53 54 size_t current_index_; 55 }; 56 57 // Provides a virtual container implementing begin() and end() for a 58 // sequence of deps. This can then be used in range-based for loops. 59 class DepsIteratorRange { 60 public: 61 explicit DepsIteratorRange(const DepsIterator& b); 62 ~DepsIteratorRange(); 63 begin()64 const DepsIterator& begin() const { return begin_; } end()65 const DepsIterator& end() const { return end_; } 66 67 private: 68 DepsIterator begin_; 69 DepsIterator end_; 70 }; 71 72 #endif // TOOLS_GN_DEPS_ITERATOR_H_ 73