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- /*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef SkRecordPattern_DEFINED
- #define SkRecordPattern_DEFINED
- #include "include/private/SkTLogic.h"
- #include "src/core/SkRecord.h"
- namespace SkRecords {
- // First, some matchers. These match a single command in the SkRecord,
- // and may hang onto some data from it. If so, you can get the data by calling .get().
- // Matches a command of type T, and stores that command.
- template <typename T>
- class Is {
- public:
- Is() : fPtr(nullptr) {}
- typedef T type;
- type* get() { return fPtr; }
- bool operator()(T* ptr) {
- fPtr = ptr;
- return true;
- }
- template <typename U>
- bool operator()(U*) {
- fPtr = nullptr;
- return false;
- }
- private:
- type* fPtr;
- };
- // Matches any command that draws, and stores its paint.
- class IsDraw {
- public:
- IsDraw() : fPaint(nullptr) {}
- typedef SkPaint type;
- type* get() { return fPaint; }
- template <typename T>
- SK_WHEN((T::kTags & kDrawWithPaint_Tag) == kDrawWithPaint_Tag, bool) operator()(T* draw) {
- fPaint = AsPtr(draw->paint);
- return true;
- }
- template <typename T>
- SK_WHEN((T::kTags & kDrawWithPaint_Tag) == kDraw_Tag, bool) operator()(T* draw) {
- fPaint = nullptr;
- return true;
- }
- template <typename T>
- SK_WHEN(!(T::kTags & kDraw_Tag), bool) operator()(T* draw) {
- fPaint = nullptr;
- return false;
- }
- private:
- // Abstracts away whether the paint is always part of the command or optional.
- template <typename T> static T* AsPtr(SkRecords::Optional<T>& x) { return x; }
- template <typename T> static T* AsPtr(T& x) { return &x; }
- type* fPaint;
- };
- // Matches if Matcher doesn't. Stores nothing.
- template <typename Matcher>
- struct Not {
- template <typename T>
- bool operator()(T* ptr) { return !Matcher()(ptr); }
- };
- // Matches if any of First or Rest... does. Stores nothing.
- template <typename First, typename... Rest>
- struct Or {
- template <typename T>
- bool operator()(T* ptr) { return First()(ptr) || Or<Rest...>()(ptr); }
- };
- template <typename First>
- struct Or<First> {
- template <typename T>
- bool operator()(T* ptr) { return First()(ptr); }
- };
- // Greedy is a special matcher that greedily matches Matcher 0 or more times. Stores nothing.
- template <typename Matcher>
- struct Greedy {
- template <typename T>
- bool operator()(T* ptr) { return Matcher()(ptr); }
- };
- // Pattern matches each of its matchers in order.
- //
- // This is the main entry point to pattern matching, and so provides a couple of extra API bits:
- // - search scans through the record to look for matches;
- // - first, second, third, ... return the data stored by their respective matchers in the pattern.
- template <typename... Matchers> class Pattern;
- template <> class Pattern<> {
- public:
- // Bottoms out recursion. Just return whatever i the front decided on.
- int match(SkRecord*, int i) { return i; }
- };
- template <typename First, typename... Rest>
- class Pattern<First, Rest...> {
- public:
- // If this pattern matches the SkRecord starting from i,
- // return the index just past the end of the pattern, otherwise return 0.
- SK_ALWAYS_INLINE int match(SkRecord* record, int i) {
- i = this->matchFirst(&fFirst, record, i);
- return i > 0 ? fRest.match(record, i) : 0;
- }
- // Starting from *end, walk through the SkRecord to find the first span matching this pattern.
- // If there is no such span, return false. If there is, return true and set [*begin, *end).
- SK_ALWAYS_INLINE bool search(SkRecord* record, int* begin, int* end) {
- for (*begin = *end; *begin < record->count(); ++(*begin)) {
- *end = this->match(record, *begin);
- if (*end != 0) {
- return true;
- }
- }
- return false;
- }
- // TODO: some sort of smart get<i>()
- template <typename T> T* first() { return fFirst.get(); }
- template <typename T> T* second() { return fRest.template first<T>(); }
- template <typename T> T* third() { return fRest.template second<T>(); }
- template <typename T> T* fourth() { return fRest.template third<T>(); }
- private:
- // If first isn't a Greedy, try to match at i once.
- template <typename T>
- int matchFirst(T* first, SkRecord* record, int i) {
- if (i < record->count()) {
- if (record->mutate(i, *first)) {
- return i+1;
- }
- }
- return 0;
- }
- // If first is a Greedy, walk i until it doesn't match.
- template <typename T>
- int matchFirst(Greedy<T>* first, SkRecord* record, int i) {
- while (i < record->count()) {
- if (!record->mutate(i, *first)) {
- return i;
- }
- i++;
- }
- return 0;
- }
- First fFirst;
- Pattern<Rest...> fRest;
- };
- } // namespace SkRecords
- #endif//SkRecordPattern_DEFINED
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