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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/base/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>
+ std::enable_if_t<(T::kTags & kDrawWithPaint_Tag) == kDrawWithPaint_Tag, bool>
+ operator()(T* draw) {
+ fPaint = AsPtr(draw->paint);
+ return true;
+ }
+
+ template <typename T>
+ std::enable_if_t<(T::kTags & kDrawWithPaint_Tag) == kDraw_Tag, bool> operator()(T* draw) {
+ fPaint = nullptr;
+ return true;
+ }
+
+ template <typename T>
+ std::enable_if_t<!(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