Generate path names on the client side

Pre-allocates a range of path names and manages allocations within
that range on the client side. This allows us to generate new path
objects in a feed-forward manner that doesn't require round trips to
the GL server.

BUG=skia:
R=bsalomon@google.com, markkilgard@gmail.com

Author: cdalton@nvidia.com

Review URL: https://codereview.chromium.org/304403003

1 files changed, 169 insertions, 0 deletions

diff --git a/tests/NameAllocatorTest.cpp b/tests/NameAllocatorTest.cpp
new file mode 100644
index 0000000000..86efdb2f72
--- /dev/null
+++ b/tests/NameAllocatorTest.cpp
@@ -0,0 +1,169 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#if SK_SUPPORT_GPU
+
+#include "gl/GrGLNameAllocator.h"
+#include "Test.h"
+
+////////////////////////////////////////////////////////////////////////////////
+
+class NameLeakTest {
+    static const GrGLuint kFirstName = 101;
+    static const GrGLuint kRange = 1013;
+
+public:
+    NameLeakTest(skiatest::Reporter* reporter)
+        : fReporter(reporter),
+          fAllocator(kFirstName, kFirstName + kRange),
+          fAllocatedCount(0),
+          fRandomName(kFirstName + 4 * kRange / 7) {
+        memset(fAllocatedNames, 0, sizeof(fAllocatedNames));
+    }
+
+    bool run() {
+        if (!this->allocateAllRemaining()) {
+            return false;
+        }
+
+        for (GrGLuint freeCount = 1; freeCount <= kRange; ++freeCount) {
+            if (!this->freeRandomNames(freeCount)) {
+                return false;
+            }
+            if (!this->allocateAllRemaining()) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+private:
+    bool isAllocated(GrGLuint name) const {
+        return fAllocatedNames[name - kFirstName];
+    }
+
+    void setAllocated(GrGLuint name, bool allocated) {
+        fAllocatedNames[name - kFirstName] = allocated;
+    }
+
+    bool allocateAllRemaining() {
+        for (; fAllocatedCount < kRange; ++fAllocatedCount) {
+            GrGLuint name = fAllocator.allocateName();
+            if (0 == name) {
+                ERRORF(fReporter,
+                       "Name allocate failed, but there should still be %u free names",
+                       kRange - fAllocatedCount);
+                return false;
+            }
+            if (name < kFirstName || name >= kFirstName + kRange) {
+                ERRORF(fReporter,
+                       "Name allocate returned name %u outside its bounds [%u, %u)",
+                       name, kFirstName, kFirstName + kRange);
+                return false;
+            }
+            if (this->isAllocated(name)) {
+                ERRORF(fReporter, "Name allocate returned name that is already allocated");
+                return false;
+            }
+
+            this->setAllocated(name, true);
+        }
+
+        // Ensure it returns 0 once all the names are allocated.
+        GrGLuint name = fAllocator.allocateName();
+        if (0 != name) {
+            ERRORF(fReporter,
+                   "Name allocate did not fail when all names were already in use");
+            return false;
+        }
+
+        // Ensure every unique name is allocated.
+        for (GrGLuint i = 0; i < kRange; ++i) {
+            if (!this->isAllocated(kFirstName + i)) {
+                ERRORF(fReporter, "Not all unique names are allocated after allocateAllRemaining()");
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    bool freeRandomNames(GrGLuint count) {
+        // The values a and c make up an LCG (pseudo-random generator). These
+        // values must satisfy the Hull-Dobell Theorem (with m=kRange):
+        // http://en.wikipedia.org/wiki/Linear_congruential_generator
+        // We use our own generator to guarantee it hits each unique value
+        // within kRange exactly once before repeating.
+        const GrGLuint seed = (count + fRandomName) / 2;
+        const GrGLuint a = seed * kRange + 1;
+        const GrGLuint c = (seed * 743) % kRange;
+
+        for (GrGLuint i = 0; i < count; ++i) {
+            fRandomName = (a * fRandomName + c) % kRange;
+            const GrGLuint name = kFirstName + fRandomName;
+            if (!this->isAllocated(name)) {
+                ERRORF(fReporter, "Test bug: Should not free a not-allocated name at this point (%u)", i);
+                return false;
+            }
+
+            fAllocator.free(name);
+            this->setAllocated(name, false);
+            --fAllocatedCount;
+        }
+
+        return true;
+    }
+
+    skiatest::Reporter* fReporter;
+    GrGLNameAllocator fAllocator;
+    bool fAllocatedNames[kRange];
+    GrGLuint fAllocatedCount;
+    GrGLuint fRandomName;
+};
+
+DEF_GPUTEST(NameAllocator, reporter, factory) {
+    // Ensure no names are leaked or double-allocated during heavy usage.
+    {
+        NameLeakTest nameLeakTest(reporter);
+        nameLeakTest.run();
+    }
+
+    static const GrGLuint range = 32;
+    GrGLNameAllocator allocator(1, 1 + range);
+    for (GrGLuint i = 1; i <= range; ++i) {
+        allocator.allocateName();
+    }
+    REPORTER_ASSERT(reporter, 0 == allocator.allocateName());
+
+    // Test freeing names out of range.
+    allocator.free(allocator.firstName() - 1);
+    allocator.free(allocator.endName());
+    REPORTER_ASSERT(reporter, 0 == allocator.allocateName());
+
+    // Test freeing not-allocated names.
+    for (GrGLuint i = 1; i <= range/2; i += 2) {
+        allocator.free(i);
+    }
+    for (GrGLuint i = 1; i <= range/2; i += 2) {
+        // None of these names will be allocated.
+        allocator.free(i);
+    }
+    for (GrGLuint i = 1; i <= range/2; ++i) {
+        // Every other name will not be be allocated.
+        allocator.free(i);
+    }
+    for (GrGLuint i = 1; i <= range/2; ++i) {
+        if (0 == allocator.allocateName()) {
+            ERRORF(reporter, "Name allocate failed when there should be free names");
+            break;
+        }
+    }
+    REPORTER_ASSERT(reporter, 0 == allocator.allocateName());
+}
+
+#endif