Add SkTLList, linked list class implemented on top of the internal llist class.

R=robertphillips@google.com
Committed: https://code.google.com/p/skia/source/detail?r=6644
Review URL: https://codereview.appspot.com/6869049

git-svn-id: http://skia.googlecode.com/svn/trunk@6647 2bbb7eff-a529-9590-31e7-b0007b416f81

gyp/core.gypi

@@ -164,6 +164,7 @@
         '<(skia_src_path)/core/SkTextFormatParams.h',
         '<(skia_src_path)/core/SkTileGrid.cpp',
         '<(skia_src_path)/core/SkTileGrid.h',
+        '<(skia_src_path)/core/SkTLList.h',
         '<(skia_src_path)/core/SkTLS.cpp',
         '<(skia_src_path)/core/SkTSearch.cpp',
         '<(skia_src_path)/core/SkTSort.h',

gyp/tests.gyp

@@ -56,6 +56,7 @@
         '../tests/GrMemoryPoolTest.cpp',
         '../tests/HashCacheTest.cpp',
         '../tests/InfRectTest.cpp',
+        '../tests/LListTest.cpp',
         '../tests/MathTest.cpp',
         '../tests/MatrixTest.cpp',
         '../tests/Matrix44Test.cpp',
@@ -91,7 +92,6 @@
         '../tests/StreamTest.cpp',
         '../tests/StringTest.cpp',
         '../tests/StrokeTest.cpp',
-        '../tests/TDLinkedListTest.cpp',
         '../tests/Test.cpp',
         '../tests/Test.h',
         '../tests/TestSize.cpp',

src/core/SkTLList.h

@@ -0,0 +1,272 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTInternalLList.h"
+#include "SkTemplates.h"
+
+/** Doubly-linked list of objects. The objects' lifetimes are controlled by the list. I.e. the
+    the list creates the objects and they are deleted upon removal. This class block-allocates
+    space for entries based on a param passed to the constructor. */
+template <typename T>
+class SkTLList : public SkNoncopyable {
+private:
+    struct Block;
+    struct Node {
+        char fObj[sizeof(T)];
+        SK_DECLARE_INTERNAL_LLIST_INTERFACE(Node);
+        Block* fBlock; // owning block.
+    };
+    typedef SkTInternalLList<Node> NodeList;
+
+public:
+    /** allocCnt is the number of objects to allocate as a group. In the worst case fragmentation
+        each object is using the space required for allocCnt unfragmented objects. */
+    SkTLList(int allocCnt = 1) : fCount(0), fAllocCnt(allocCnt) {
+        SkASSERT(allocCnt > 0);
+        this->validate();
+    }
+
+    ~SkTLList() {
+        this->validate();
+        typename NodeList::Iter iter;
+        Node* node = iter.init(fList, Iter::kHead_IterStart);
+        while (NULL != node) {
+            reinterpret_cast<T*>(node->fObj)->~T();
+            Block* block = node->fBlock;
+            node = iter.next();
+            if (0 == --block->fNodesInUse) {
+                for (int i = 0; i < fAllocCnt; ++i) {
+                    block->fNodes[i].~Node();
+                }
+                sk_free(block);
+            }
+        }
+    }
+    
+    void addToHead(const T& t) {
+        this->validate();
+        Node* node = this->createNode();
+        fList.addToHead(node);
+        SkNEW_PLACEMENT_ARGS(node->fObj, T, (t));
+        this->validate();
+    }
+
+    void addToTail(const T& t) {
+        this->validate();
+        Node* node = this->createNode();
+        fList.addToTail(node);
+        SkNEW_PLACEMENT_ARGS(node->fObj, T, (t));
+        this->validate();
+    }
+
+    void popHead() {
+        this->validate();
+        Node* node = fList.head();
+        if (NULL != node) {
+            this->removeNode(node);
+        }
+        this->validate();
+    }
+
+    void popTail() {
+        this->validate();
+        Node* node = fList.head();
+        if (NULL != node) {
+            this->removeNode(node);
+        }
+        this->validate();
+    }
+
+    void remove(T* t) {
+        this->validate();
+        Node* node = reinterpret_cast<Node*>(t);
+        SkASSERT(reinterpret_cast<T*>(node->fObj) == t);
+        this->removeNode(node);
+        this->validate();
+    }
+
+    void reset() {
+        this->validate();
+        Iter iter(*this, Iter::kHead_IterStart);
+        while (iter.get()) {
+            Iter next = iter;
+            next.next();
+            this->remove(iter.get());
+            iter = next;
+        }
+        SkASSERT(0 == fCount);
+        this->validate();
+    }
+
+    int count() const { return fCount; }
+    bool isEmpty() const { this->validate(); return 0 == fCount; }
+
+    bool operator== (const SkTLList& list) const {
+        if (this == &list) {
+            return true;
+        }
+        if (fCount != list.fCount) {
+            return false;
+        }
+        for (Iter a(*this, Iter::kHead_IterStart), b(list, Iter::kHead_IterStart);
+             a.get();
+             a.next(), b.next()) {
+            SkASSERT(NULL != b.get()); // already checked that counts match.
+            if (!(*a.get() == *b.get())) {
+                return false;
+            }
+        }
+        return true;
+    }
+    bool operator!= (const SkTLList& list) const { return !(*this == list); }
+
+    /** The iterator becomes invalid if the element it refers to is removed from the list. */
+    class Iter : private NodeList::Iter {
+    private:
+        typedef typename NodeList::Iter INHERITED;
+
+    public:
+        typedef typename INHERITED::IterStart IterStart;
+        //!< Start the iterator at the head of the list.
+        static const IterStart kHead_IterStart = INHERITED::kHead_IterStart;
+        //!< Start the iterator at the tail of the list.
+        static const IterStart kTail_IterStart = INHERITED::kTail_IterStart;
+
+        Iter() {}
+
+        Iter(const SkTLList& list, IterStart start) {
+            INHERITED::init(list.fList, start);
+        }
+
+        T* init(const SkTLList& list, IterStart start) {
+            return this->nodeToObj(INHERITED::init(list.fList, start));
+        }
+
+        T* get() { return this->nodeToObj(INHERITED::get()); }
+
+        T* next() { return this->nodeToObj(INHERITED::next()); }
+
+        T* prev() { return this->nodeToObj(INHERITED::prev()); }
+
+        Iter& operator= (const Iter& iter) { INHERITED::operator=(iter); return *this; }
+
+    private:
+        T* nodeToObj(Node* node) {
+            if (NULL != node) {
+                return reinterpret_cast<T*>(node->fObj);
+            } else {
+                return NULL;
+            }
+        }
+    };
+
+private:
+    struct Block {
+        int fNodesInUse;
+        Node fNodes[1];
+    };
+
+    size_t blockSize() const { return sizeof(Block) + sizeof(Node) * (fAllocCnt-1); }
+
+    Node* createNode() {
+        Node* node = fFreeList.head();
+        if (NULL != node) {
+            fFreeList.remove(node);
+            ++node->fBlock->fNodesInUse;
+        } else {
+            Block* block = reinterpret_cast<Block*>(sk_malloc_flags(this->blockSize(), 0));
+            node = &block->fNodes[0];
+            SkNEW_PLACEMENT(node, Node);
+            node->fBlock = block;
+            block->fNodesInUse = 1;
+            for (int i = 1; i < fAllocCnt; ++i) {
+                SkNEW_PLACEMENT(block->fNodes + i, Node);
+                fFreeList.addToHead(block->fNodes + i);
+                block->fNodes[i].fBlock = block;
+            }
+        }
+        ++fCount;
+        return node;
+    }
+
+    void removeNode(Node* node) {
+        SkASSERT(NULL != node);
+        fList.remove(node);
+        reinterpret_cast<T*>(node->fObj)->~T();
+        if (0 == --node->fBlock->fNodesInUse) {
+            // Delete a block when it no longer has any nodes in use to reduce memory consumption.
+            Block* block = node->fBlock;
+            for (int i = 0; i < fAllocCnt; ++i) {
+                if (block->fNodes + i != node) {
+                    fFreeList.remove(block->fNodes + i);
+                }
+                block->fNodes[i].~Node();
+            }
+            sk_free(block);
+        } else {
+            fFreeList.addToHead(node);
+        }
+        --fCount;
+        this->validate();
+    }
+
+    void validate() const {
+#ifdef SK_DEBUG
+        SkASSERT((0 == fCount) == fList.isEmpty());
+        SkASSERT((0 != fCount) || fFreeList.isEmpty());
+
+        fList.validate();
+        fFreeList.validate();
+        typename NodeList::Iter iter;
+        Node* freeNode = iter.init(fFreeList, Iter::kHead_IterStart);
+        while (freeNode) {
+            SkASSERT(fFreeList.isInList(freeNode));
+            Block* block = freeNode->fBlock;
+            SkASSERT(block->fNodesInUse > 0 && block->fNodesInUse < fAllocCnt);
+
+            int activeCnt = 0;
+            int freeCnt = 0;
+            for (int i = 0; i < fAllocCnt; ++i) {
+                bool free = fFreeList.isInList(block->fNodes + i);
+                bool active = fList.isInList(block->fNodes + i);
+                SkASSERT(free != active);
+                activeCnt += active;
+                freeCnt += free;
+            }
+            SkASSERT(activeCnt == block->fNodesInUse);
+            freeNode = iter.next();
+        }
+
+        int count = 0;
+        Node* activeNode = iter.init(fList, Iter::kHead_IterStart);
+        while (activeNode) {
+            ++count;
+            SkASSERT(fList.isInList(activeNode));
+            Block* block = activeNode->fBlock;
+            SkASSERT(block->fNodesInUse > 0 && block->fNodesInUse <= fAllocCnt);
+
+            int activeCnt = 0;
+            int freeCnt = 0;
+            for (int i = 0; i < fAllocCnt; ++i) {
+                bool free = fFreeList.isInList(block->fNodes + i);
+                bool active = fList.isInList(block->fNodes + i);
+                SkASSERT(free != active);
+                activeCnt += active;
+                freeCnt += free;
+            }
+            SkASSERT(activeCnt == block->fNodesInUse);
+            activeNode = iter.next();
+        }
+        SkASSERT(count == fCount);
+#endif
+    }
+
+    NodeList fList;
+    NodeList fFreeList;
+    int fCount;
+    int fAllocCnt;
+};

tests/LListTest.cpp

@@ -0,0 +1,233 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+#include "SkRandom.h"
+#include "SkTInternalLList.h"
+#include "SkTLList.h"
+
+class ListElement {
+public:
+    ListElement(int id) : fID(id) {
+    }
+    bool operator== (const ListElement& other) { return fID == other.fID; }
+
+#ifdef SK_ENABLE_INST_COUNT
+    // Make the instance count available publicly.
+    static int InstanceCount() { return GetInstanceCount(); }
+#endif
+
+    int fID;
+
+private:
+    SK_DECLARE_INST_COUNT_ROOT(ListElement);
+    SK_DECLARE_INTERNAL_LLIST_INTERFACE(ListElement);
+};
+
+SK_DEFINE_INST_COUNT(ListElement);
+
+static void check_list(const SkTInternalLList<ListElement>& list,
+                       skiatest::Reporter* reporter,
+                       bool empty,
+                       int numElements,
+                       bool in0, bool in1, bool in2, bool in3,
+                       ListElement elements[4]) {
+
+    REPORTER_ASSERT(reporter, empty == list.isEmpty());
+#if SK_DEBUG
+    REPORTER_ASSERT(reporter, numElements == list.countEntries());
+    REPORTER_ASSERT(reporter, in0 == list.isInList(&elements[0]));
+    REPORTER_ASSERT(reporter, in1 == list.isInList(&elements[1]));
+    REPORTER_ASSERT(reporter, in2 == list.isInList(&elements[2]));
+    REPORTER_ASSERT(reporter, in3 == list.isInList(&elements[3]));
+#endif
+}
+
+static void TestTInternalLList(skiatest::Reporter* reporter) {
+    SkTInternalLList<ListElement> list;
+    ListElement elements[4] = {
+        ListElement(0),
+        ListElement(1),
+        ListElement(2),
+        ListElement(3),
+    };
+
+    // list should be empty to start with
+    check_list(list, reporter, true, 0, false, false, false, false, elements);
+
+    list.addToHead(&elements[0]);
+
+    check_list(list, reporter, false, 1, true, false, false, false, elements);
+
+    list.addToHead(&elements[1]);
+    list.addToHead(&elements[2]);
+    list.addToHead(&elements[3]);
+
+    check_list(list, reporter, false, 4, true, true, true, true, elements);
+
+    // test out iterators
+    typedef SkTInternalLList<ListElement>::Iter Iter;
+    Iter iter;
+
+    ListElement* cur = iter.init(list, Iter::kHead_IterStart);
+    for (int i = 0; NULL != cur; ++i, cur = iter.next()) {
+        REPORTER_ASSERT(reporter, cur->fID == 3-i);
+    }
+
+    cur = iter.init(list, Iter::kTail_IterStart);
+    for (int i = 0; NULL != cur; ++i, cur = iter.prev()) {
+        REPORTER_ASSERT(reporter, cur->fID == i);
+    }
+
+    // remove middle, frontmost then backmost
+    list.remove(&elements[1]);
+    list.remove(&elements[3]);
+    list.remove(&elements[0]);
+
+    check_list(list, reporter, false, 1, false, false, true, false, elements);
+
+    // remove last element
+    list.remove(&elements[2]);
+
+    // list should be empty again
+    check_list(list, reporter, true, 0, false, false, false, false, elements);
+}
+
+static void TestTLList(skiatest::Reporter* reporter) {
+    typedef SkTLList<ListElement> ElList;
+    typedef ElList::Iter Iter;
+    SkRandom random;
+
+    for (int i = 1; i <= 16; i *= 2) {
+
+        ElList list1(i);
+        ElList list2(i);
+        Iter iter1;
+        Iter iter2;
+        Iter iter3;
+        Iter iter4;
+
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(0 == ListElement::InstanceCount());
+#endif
+
+        REPORTER_ASSERT(reporter, list1.isEmpty());
+        REPORTER_ASSERT(reporter, NULL == iter1.init(list1, Iter::kHead_IterStart));
+        REPORTER_ASSERT(reporter, NULL == iter1.init(list1, Iter::kTail_IterStart));
+        // Try popping an empty list
+        list1.popHead();
+        list1.popTail();
+        REPORTER_ASSERT(reporter, list1.isEmpty());
+        REPORTER_ASSERT(reporter, list1 == list2);
+
+        // Create two identical lists, one by appending to head and the other to the tail.
+        list1.addToHead(ListElement(1));
+        list2.addToTail(ListElement(1));
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(2 == ListElement::InstanceCount());
+#endif
+        iter1.init(list1, Iter::kHead_IterStart);
+        iter2.init(list1, Iter::kTail_IterStart);
+        REPORTER_ASSERT(reporter, iter1.get()->fID == iter2.get()->fID);
+        iter3.init(list2, Iter::kHead_IterStart);
+        iter4.init(list2, Iter::kTail_IterStart);
+        REPORTER_ASSERT(reporter, iter3.get()->fID == iter1.get()->fID);
+        REPORTER_ASSERT(reporter, iter4.get()->fID == iter1.get()->fID);
+        REPORTER_ASSERT(reporter, list1 == list2);
+    
+        // add an element to the second list, check that iters are still valid
+        list2.addToHead(ListElement(2));
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(3 == ListElement::InstanceCount());
+#endif
+        REPORTER_ASSERT(reporter, iter3.get()->fID == iter1.get()->fID);
+        REPORTER_ASSERT(reporter, iter4.get()->fID == iter1.get()->fID);
+        REPORTER_ASSERT(reporter, 1 == Iter(list2, Iter::kTail_IterStart).get()->fID);
+        REPORTER_ASSERT(reporter, 2 == Iter(list2, Iter::kHead_IterStart).get()->fID);
+        REPORTER_ASSERT(reporter, list1 != list2);
+        list1.addToHead(ListElement(2));
+        REPORTER_ASSERT(reporter, list1 == list2);
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(4 == ListElement::InstanceCount());
+#endif
+        REPORTER_ASSERT(reporter, !list1.isEmpty());
+
+        list1.reset();
+        list2.reset();
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(0 == ListElement::InstanceCount());
+#endif
+        REPORTER_ASSERT(reporter, list1.isEmpty() && list2.isEmpty());
+
+        int count = 0;
+        for (int j = 0; j < 100; ++j) {
+            if (list1.isEmpty() || random.nextBiasedBool(3  * SK_Scalar1 / 4)) {
+                int id = static_cast<int>(random.nextU());
+                if (random.nextBool()) {
+                    list1.addToHead(ListElement(id));
+                } else {
+                    list1.addToTail(ListElement(id));
+                }
+                ++count;
+            } else {
+                // walk to a random place either forward or backwards and remove.
+                int n = random.nextULessThan(list1.count());
+                Iter::IterStart start;
+                ListElement* (Iter::*incrFunc)();
+                
+                if (random.nextBool()) {
+                    start = Iter::kHead_IterStart;
+                    incrFunc = &Iter::next;
+                } else {
+                    start = Iter::kTail_IterStart;
+                    incrFunc = &Iter::prev;
+                }
+
+                // find the element
+                Iter iter(list1, start);
+                while (n--) {
+                    REPORTER_ASSERT(reporter, NULL != iter.get());
+                    (iter.*incrFunc)();
+                }
+                REPORTER_ASSERT(reporter, NULL != iter.get());
+
+                // remember the prev and next elements from the element to be removed
+                Iter prev = iter;
+                Iter next = iter;
+                prev.prev();
+                next.next();
+                list1.remove(iter.get());
+
+                // make sure the remembered next/prev iters still work
+                Iter pn = prev; pn.next();
+                Iter np = next; np.prev();
+                // pn should match next unless the target node was the head, in which case prev
+                // walked off the list.
+                REPORTER_ASSERT(reporter, pn.get() == next.get() || NULL == prev.get());
+                // Similarly, np should match prev unless next originally walked off the tail.
+                REPORTER_ASSERT(reporter, np.get() == prev.get() || NULL == next.get());
+                --count;
+            }
+            REPORTER_ASSERT(reporter, count == list1.count());
+#ifdef SK_ENABLE_INST_COUNT
+            SkASSERT(count == ListElement::InstanceCount());
+#endif
+        }
+        list1.reset();
+#ifdef SK_ENABLE_INST_COUNT
+        SkASSERT(0 == ListElement::InstanceCount());
+#endif
+    }
+}
+
+static void test_llists(skiatest::Reporter* reporter) {
+    TestTInternalLList(reporter);
+    TestTLList(reporter);
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("LList", TestLListClass, test_llists)

tests/TDLinkedListTest.cpp

@@ -1,90 +0,0 @@
-/*
- * Copyright 2012 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "Test.h"
-#include "SkTInternalLList.h"
-
-class ListElement {
-public:
-    ListElement(int id) : fID(id) {
-    }
-
-    int fID;
-
-private:
-    SK_DECLARE_INTERNAL_LLIST_INTERFACE(ListElement);
-};
-
-static void CheckList(const SkTInternalLList<ListElement>& list,
-                      skiatest::Reporter* reporter,
-                      bool empty,
-                      int numElements,
-                      bool in0, bool in1, bool in2, bool in3,
-                      ListElement elements[4]) {
-
-    REPORTER_ASSERT(reporter, empty == list.isEmpty());
-#if SK_DEBUG
-    REPORTER_ASSERT(reporter, numElements == list.countEntries());
-    REPORTER_ASSERT(reporter, in0 == list.isInList(&elements[0]));
-    REPORTER_ASSERT(reporter, in1 == list.isInList(&elements[1]));
-    REPORTER_ASSERT(reporter, in2 == list.isInList(&elements[2]));
-    REPORTER_ASSERT(reporter, in3 == list.isInList(&elements[3]));
-#endif
-}
-
-static void TestTDLinkedList(skiatest::Reporter* reporter) {
-    SkTInternalLList<ListElement> list;
-    ListElement elements[4] = {
-        ListElement(0),
-        ListElement(1),
-        ListElement(2),
-        ListElement(3),
-    };
-
-    // list should be empty to start with
-    CheckList(list, reporter, true, 0, false, false, false, false, elements);
-
-    list.addToHead(&elements[0]);
-
-    CheckList(list, reporter, false, 1, true, false, false, false, elements);
-
-    list.addToHead(&elements[1]);
-    list.addToHead(&elements[2]);
-    list.addToHead(&elements[3]);
-
-    CheckList(list, reporter, false, 4, true, true, true, true, elements);
-
-    // test out iterators
-    typedef SkTInternalLList<ListElement>::Iter Iter;
-    Iter iter;
-
-    ListElement* cur = iter.init(list, Iter::kHead_IterStart);
-    for (int i = 0; NULL != cur; ++i, cur = iter.next()) {
-        REPORTER_ASSERT(reporter, cur->fID == 3-i);
-    }
-
-    cur = iter.init(list, Iter::kTail_IterStart);
-    for (int i = 0; NULL != cur; ++i, cur = iter.prev()) {
-        REPORTER_ASSERT(reporter, cur->fID == i);
-    }
-
-    // remove middle, frontmost then backmost
-    list.remove(&elements[1]);
-    list.remove(&elements[3]);
-    list.remove(&elements[0]);
-
-    CheckList(list, reporter, false, 1, false, false, true, false, elements);
-
-    // remove last element
-    list.remove(&elements[2]);
-
-    // list should be empty again
-    CheckList(list, reporter, true, 0, false, false, false, false, elements);
-}
-
-#include "TestClassDef.h"
-DEFINE_TESTCLASS("TDLinkedList", TestTDLinkedListClass, TestTDLinkedList)