Improve null gpu's memory handling

src/gpu/gl/GrGLCreateNullInterface.cpp

Index: src/gpu/gl/GrGLCreateNullInterface.cpp
===================================================================
--- src/gpu/gl/GrGLCreateNullInterface.cpp	(revision 10138)
+++ src/gpu/gl/GrGLCreateNullInterface.cpp	(working copy)
@@ -15,13 +15,90 @@
 
 namespace { // added to suppress 'no previous prototype' warning
 
+class GrBufferObj {
+public:
+    GrBufferObj() : fDataPtr(NULL), fSize(0), fMapped(false) {
+        static GrGLuint gNextID = 0;     // 0 is reserved
+
+        fID = ++gNextID;
+    }
+    ~GrBufferObj() { SkDELETE_ARRAY(fDataPtr); }
+
+    void allocate(GrGLint size, const GrGLchar *dataPtr) {

[tfarina, 2013/07/18 16:30:21]

nit: GrGLChar* 

[robertphillips, 2013/07/18 16:59:31]

Done.

+        if (NULL != fDataPtr) {
+            GrAssert(0 != fSize);
+            SkDELETE_ARRAY(fDataPtr);
+        }
+
+        fSize = size;
+        fDataPtr = SkNEW_ARRAY(char, size);
+    }
+
+    GrGLuint id() const          { return fID; }
+    GrGLchar *dataPtr()          { return fDataPtr; }

[tfarina, 2013/07/18 16:30:21]

nit: GrGLChar*

[robertphillips, 2013/07/18 16:59:31]

Done.

+    GrGLint size() const         { return fSize; }
+
+    void setMapped(bool mapped)  { fMapped = mapped; }
+    bool mapped() const          { return fMapped; }
+
+private:
+    GrGLuint     fID;
+    GrGLchar*    fDataPtr;
+    GrGLint      fSize;         // size in bytes
+    bool         fMapped;
+};
+
+// In debug builds we do asserts that ensure we agree with GL about when a buffer
+// is mapped.
+static SkTDArray<GrBufferObj*> gBuffers;
+static GrGLuint gCurrArrayBuffer;
+static GrGLuint gCurrElementArrayBuffer;
+
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLActiveTexture(GrGLenum texture) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLAttachShader(GrGLuint program, GrGLuint shader) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLBeginQuery(GrGLenum target, GrGLuint id) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLBindAttribLocation(GrGLuint program, GrGLuint index, const char* name) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLBindTexture(GrGLenum target, GrGLuint texture) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLBindVertexArray(GrGLuint id) {}
-GrGLvoid GR_GL_FUNCTION_TYPE nullGLBufferData(GrGLenum target, GrGLsizeiptr size, const GrGLvoid* data, GrGLenum usage) {}
+
+GrGLvoid GR_GL_FUNCTION_TYPE nullGLGenBuffers(GrGLsizei n, GrGLuint* ids) {
+
+    for (int i = 0; i < n; ++i) {
+        GrBufferObj* buffer = SkNEW(GrBufferObj);
+        // This code relies on the id of the buffer being 1 more then its
+        // position in 'gBuffers'
+        GrAssert(gBuffers.count() == (int)buffer->id() - 1);
+        *gBuffers.append() = buffer;
+        ids[i] = buffer->id();
+    }
+}
+
+GrGLvoid GR_GL_FUNCTION_TYPE nullGLBufferData(GrGLenum target, 
+                                              GrGLsizeiptr size, 
+                                              const GrGLvoid* data, 
+                                              GrGLenum usage) {
+    GrGLuint id = 0;
+
+    switch (target) {
+    case GR_GL_ARRAY_BUFFER:
+        id = gCurrArrayBuffer;
+        break;
+    case GR_GL_ELEMENT_ARRAY_BUFFER:
+        id = gCurrElementArrayBuffer;
+        break;
+    default:
+        GrCrash("Unexpected target to nullGLBufferData");
+        break;
+    }
+
+    if (id > 0) {
+        GrBufferObj* buffer = gBuffers[id-1];
+        GrAssert(NULL != buffer && buffer->id() == id);
+
+        buffer->allocate(size, (const GrGLchar*) data);
+    }
+}
+
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLPixelStorei(GrGLenum pname, GrGLint param) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLReadPixels(GrGLint x, GrGLint y, GrGLsizei width, GrGLsizei height, GrGLenum format, GrGLenum type, GrGLvoid* pixels) {}
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLUseProgram(GrGLuint program) {}
@@ -34,12 +111,12 @@
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLFramebufferTexture2D(GrGLenum target, GrGLenum attachment, GrGLenum textarget, GrGLuint texture, GrGLint level) {}
 
 GrGLuint GR_GL_FUNCTION_TYPE nullGLCreateProgram() {
-    static int gCurrID = 0;
+    static GrGLuint gCurrID = 0;
     return ++gCurrID;
 }
 
 GrGLuint GR_GL_FUNCTION_TYPE nullGLCreateShader(GrGLenum type) {
-    static int gCurrID = 0;
+    static GrGLuint gCurrID = 0;
     return ++gCurrID;
 }
 
@@ -47,12 +124,6 @@
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLDelete(GrGLuint program) {
 }
 
-// In debug builds we do asserts that ensure we agree with GL about when a buffer
-// is mapped.
-static SkTDArray<GrGLuint> gMappedBuffers;
-static GrGLuint gCurrArrayBuffer;
-static GrGLuint gCurrElementArrayBuffer;
-
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLBindBuffer(GrGLenum target, GrGLuint buffer) {
     switch (target) {
     case GR_GL_ARRAY_BUFFER:
@@ -73,75 +144,82 @@
         if (ids[i] == gCurrElementArrayBuffer) {
             gCurrElementArrayBuffer = 0;
         }
-        for (int j = 0; j < gMappedBuffers.count(); ++j) {
-            if (gMappedBuffers[j] == ids[i]) {
-                gMappedBuffers.remove(j);
-                // don't break b/c we didn't check for dupes on insert
-                --j;
-            }
-        }
+
+        GrBufferObj* buffer = gBuffers[ids[i]-1];
+        GrAssert(NULL != buffer && ids[i] == buffer->id());
+
+        SkDELETE(buffer);
+        gBuffers[ids[i]-1] = NULL;
     }
 }
 
 GrGLvoid* GR_GL_FUNCTION_TYPE nullGLMapBuffer(GrGLenum target, GrGLenum access) {
-    // We just reserve 32MB of RAM for all locks and hope its big enough
-    static SkAutoMalloc gBufferData(32 * (1 << 20));
-    GrGLuint buf = 0;
+
+    GrGLuint id = 0;
     switch (target) {
         case GR_GL_ARRAY_BUFFER:
-            buf = gCurrArrayBuffer;
+            id = gCurrArrayBuffer;
             break;
         case GR_GL_ELEMENT_ARRAY_BUFFER:
-            buf = gCurrElementArrayBuffer;
+            id = gCurrElementArrayBuffer;
             break;
     }
-    if (buf) {
-        *gMappedBuffers.append() = buf;
+
+    if (id > 0) {
+        GrBufferObj* buffer = gBuffers[id-1];
+        GrAssert(NULL != buffer && buffer->id() == id);
+
+        GrAssert(!buffer->mapped());
+        buffer->setMapped(true);
+        return buffer->dataPtr();
     }
-    return gBufferData.get();
+
+    GrAssert(false);
+    return NULL;            // no buffer bound to target
 }
 
 GrGLboolean GR_GL_FUNCTION_TYPE nullGLUnmapBuffer(GrGLenum target) {
-    GrGLuint buf = 0;
+    GrGLuint id = 0;
     switch (target) {
     case GR_GL_ARRAY_BUFFER:
-        buf = gCurrArrayBuffer;
+        id = gCurrArrayBuffer;
         break;
     case GR_GL_ELEMENT_ARRAY_BUFFER:
-        buf = gCurrElementArrayBuffer;
+        id = gCurrElementArrayBuffer;
         break;
     }
-    if (buf) {
-        for (int i = 0; i < gMappedBuffers.count(); ++i) {
-            if (gMappedBuffers[i] == buf) {
-                gMappedBuffers.remove(i);
-                // don't break b/c we didn't check for dupes on insert
-                --i;
-            }
-        }
+    if (id > 0) {
+        GrBufferObj* buffer = gBuffers[id-1];
+        GrAssert(NULL != buffer && buffer->id() == id);
+        GrAssert(buffer->mapped());
+
+        buffer->setMapped(false);
+        return GR_GL_TRUE;
     }
-    return GR_GL_TRUE;
+
+    GrAlwaysAssert(false);
+    return GR_GL_FALSE; // GR_GL_INVALID_OPERATION;
 }
 
 GrGLvoid GR_GL_FUNCTION_TYPE nullGLGetBufferParameteriv(GrGLenum target, GrGLenum pname, GrGLint* params) {
     switch (pname) {
         case GR_GL_BUFFER_MAPPED: {
             *params = GR_GL_FALSE;
-            GrGLuint buf = 0;
+            GrGLuint id = 0;
             switch (target) {
                 case GR_GL_ARRAY_BUFFER:
-                    buf = gCurrArrayBuffer;
+                    id = gCurrArrayBuffer;
                     break;
                 case GR_GL_ELEMENT_ARRAY_BUFFER:
-                    buf = gCurrElementArrayBuffer;
+                    id = gCurrElementArrayBuffer;
                     break;
             }
-            if (buf) {
-                for (int i = 0; i < gMappedBuffers.count(); ++i) {
-                    if (gMappedBuffers[i] == buf) {
-                        *params = GR_GL_TRUE;
-                        break;
-                    }
+            if (id > 0) {
+                GrBufferObj* buffer = gBuffers[id-1];
+                GrAssert(NULL != buffer && buffer->id() == id);
+
+                if (buffer->mapped()) {
+                    *params = GR_GL_TRUE;
                 }
             }
             break; }
@@ -202,7 +280,7 @@
         interface->fFinish = noOpGLFinish;
         interface->fFlush = noOpGLFlush;
         interface->fFrontFace = noOpGLFrontFace;
-        interface->fGenBuffers = noOpGLGenIds;
+        interface->fGenBuffers = nullGLGenBuffers;
         interface->fGenQueries = noOpGLGenIds;
         interface->fGenTextures = noOpGLGenIds;
         interface->fGenVertexArrays = noOpGLGenIds;