Use ashmem for CursorWindows.

Bug: 5332296

The memory dealer introduces additional delays for reclaiming
the memory owned by CursorWindows because the Binder object must
be finalized.  Using ashmem instead gives CursorWindow more
direct control over the lifetime of the shared memory region.

The provider now allocates the CursorWindows and returns them
to clients with a read-only protection bit set on the ashmem
region.

Improved the encapsulation of CursorWindow.  Callers shouldn't
need to care about details like how string fields are allocated.

Removed the compile-time configuration of string and numeric
storage modes to remove some dead weight.

Change-Id: I07c2bc2a9c573d7e435dcaecd269d25ea9807acd

1 files changed, 131 insertions, 160 deletions

diff --git a/include/binder/CursorWindow.h b/include/binder/CursorWindow.h
index d227244..5d490ed 100644
--- a/include/binder/CursorWindow.h
+++ b/include/binder/CursorWindow.h
@@ -21,18 +21,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#include <binder/IMemory.h>
-#include <utils/RefBase.h>
-
-#define DEFAULT_WINDOW_SIZE 4096
-#define WINDOW_ALLOCATION_SIZE 4096
-
-#define ROW_SLOT_CHUNK_NUM_ROWS 16
-
-// Row slots are allocated in chunks of ROW_SLOT_CHUNK_NUM_ROWS,
-// with an offset after the rows that points to the next chunk
-#define ROW_SLOT_CHUNK_SIZE ((ROW_SLOT_CHUNK_NUM_ROWS * sizeof(row_slot_t)) + sizeof(uint32_t))
-
+#include <binder/Parcel.h>
+#include <utils/String8.h>
 
 #if LOG_NDEBUG
 
@@ -46,176 +36,157 @@
 
 #endif
 
-
-// When defined to true strings are stored as UTF8, otherwise they're UTF16
-#define WINDOW_STORAGE_UTF8 1
-
-// When defined to true numberic values are stored inline in the field_slot_t, otherwise they're allocated in the window
-#define WINDOW_STORAGE_INLINE_NUMERICS 1
-
 namespace android {
 
-typedef struct
-{
-    uint32_t numRows;
-    uint32_t numColumns;
-} window_header_t;
-
-typedef struct
-{
-    uint32_t offset;
-} row_slot_t;
-
-typedef struct
-{
-    uint8_t type;
-    union {
-        double d;
-        int64_t l;
-        struct {
-            uint32_t offset;
-            uint32_t size;
-        } buffer;
-    } data;
-} __attribute__((packed)) field_slot_t;
-
-#define FIELD_TYPE_NULL 0
-#define FIELD_TYPE_INTEGER 1
-#define FIELD_TYPE_FLOAT 2
-#define FIELD_TYPE_STRING 3
-#define FIELD_TYPE_BLOB 4
-
 /**
  * This class stores a set of rows from a database in a buffer. The begining of the
- * window has first chunk of row_slot_ts, which are offsets to the row directory, followed by
- * an offset to the next chunk in a linked-list of additional chunk of row_slot_ts in case
+ * window has first chunk of RowSlots, which are offsets to the row directory, followed by
+ * an offset to the next chunk in a linked-list of additional chunk of RowSlots in case
  * the pre-allocated chunk isn't big enough to refer to all rows. Each row directory has a
- * field_slot_t per column, which has the size, offset, and type of the data for that field.
+ * FieldSlot per column, which has the size, offset, and type of the data for that field.
  * Note that the data types come from sqlite3.h.
+ *
+ * Strings are stored in UTF-8.
  */
-class CursorWindow
-{
+class CursorWindow {
+    CursorWindow(const String8& name, int ashmemFd,
+            void* data, size_t size, bool readOnly);
+
 public:
-                        CursorWindow(size_t maxSize);
-                        CursorWindow(){}
-    bool                setMemory(const sp<IMemory>&);
-                        ~CursorWindow();
-
-    bool                initBuffer(bool localOnly);
-    sp<IMemory>         getMemory() {return mMemory;}
-
-    size_t              size() {return mSize;}
-    uint8_t *           data() {return mData;}
-    uint32_t            getNumRows() {return mHeader->numRows;}
-    uint32_t            getNumColumns() {return mHeader->numColumns;}
-    void                freeLastRow() {
-                            if (mHeader->numRows > 0) {
-                                mHeader->numRows--;
-                            }
-                        }
-    bool                setNumColumns(uint32_t numColumns)
-                            {
-                                uint32_t cur = mHeader->numColumns;
-                                if (cur > 0 && cur != numColumns) {
-                                    LOGE("Trying to go from %d columns to %d", cur, numColumns);
-                                    return false;
-                                }
-                                mHeader->numColumns = numColumns;
-                                return true;
-                            }
-
-    int32_t             freeSpace();
-
-    void                clear();
-
-                        /**
-                         * Allocate a row slot and its directory. The returned
-                         * pointer points to the begining of the row's directory
-                         * or NULL if there wasn't room. The directory is
-                         * initialied with NULL entries for each field.
-                         */
-    field_slot_t *      allocRow();
-
-                        /**
-                         * Allocate a portion of the window. Returns the offset
-                         * of the allocation, or 0 if there isn't enough space.
-                         * If aligned is true, the allocation gets 4 byte alignment.
-                         */
-    uint32_t            alloc(size_t size, bool aligned = false);
-
-                        /**
-                         * Copy data into the window at the given offset.
-                         */
-    void                copyIn(uint32_t offset, uint8_t const * data, size_t size);
-    void                copyIn(uint32_t offset, int64_t data);
-    void                copyIn(uint32_t offset, double data);
-
-    void                copyOut(uint32_t offset, uint8_t * data, size_t size);
-    int64_t             copyOutLong(uint32_t offset);
-    double              copyOutDouble(uint32_t offset);
-
-    bool                putLong(unsigned int row, unsigned int col, int64_t value);
-    bool                putDouble(unsigned int row, unsigned int col, double value);
-    bool                putNull(unsigned int row, unsigned int col);
-
-    bool                getLong(unsigned int row, unsigned int col, int64_t * valueOut);
-    bool                getDouble(unsigned int row, unsigned int col, double * valueOut);
-    bool                getNull(unsigned int row, unsigned int col, bool * valueOut);
-
-    uint8_t *           offsetToPtr(uint32_t offset) {return mData + offset;}
-
-    row_slot_t *        allocRowSlot();
-
-    row_slot_t *        getRowSlot(int row);
-
-                        /**
-                         * return NULL if Failed to find rowSlot or
-                         * Invalid rowSlot
-                         */
-    field_slot_t *      getFieldSlotWithCheck(int row, int column);
-    field_slot_t *      getFieldSlot(int row, int column)
-                            {
-                                int fieldDirOffset = getRowSlot(row)->offset;
-                                return ((field_slot_t *)offsetToPtr(fieldDirOffset)) + column;
-                            }
-
-    int64_t getFieldSlotValueLong(field_slot_t* fieldSlot) {
-#if WINDOW_STORAGE_INLINE_NUMERICS
+    /* Field types. */
+    enum {
+        FIELD_TYPE_NULL = 0,
+        FIELD_TYPE_INTEGER = 1,
+        FIELD_TYPE_FLOAT = 2,
+        FIELD_TYPE_STRING = 3,
+        FIELD_TYPE_BLOB = 4,
+    };
+
+    /* Opaque type that describes a field slot. */
+    struct FieldSlot {
+    private:
+        int32_t type;
+        union {
+            double d;
+            int64_t l;
+            struct {
+                uint32_t offset;
+                uint32_t size;
+            } buffer;
+        } data;
+
+        friend class CursorWindow;
+    } __attribute((packed));
+
+    ~CursorWindow();
+
+    static status_t create(const String8& name, size_t size, bool localOnly,
+            CursorWindow** outCursorWindow);
+    static status_t createFromParcel(Parcel* parcel, CursorWindow** outCursorWindow);
+
+    status_t writeToParcel(Parcel* parcel);
+
+    inline String8 name() { return mName; }
+    inline size_t size() { return mSize; }
+    inline size_t freeSpace() { return mSize - mHeader->freeOffset; }
+    inline uint32_t getNumRows() { return mHeader->numRows; }
+    inline uint32_t getNumColumns() { return mHeader->numColumns; }
+
+    status_t clear();
+    status_t setNumColumns(uint32_t numColumns);
+
+    /**
+     * Allocate a row slot and its directory.
+     * The row is initialized will null entries for each field.
+     */
+    status_t allocRow();
+    status_t freeLastRow();
+
+    status_t putBlob(uint32_t row, uint32_t column, const void* value, size_t size);
+    status_t putString(uint32_t row, uint32_t column, const char* value, size_t sizeIncludingNull);
+    status_t putLong(uint32_t row, uint32_t column, int64_t value);
+    status_t putDouble(uint32_t row, uint32_t column, double value);
+    status_t putNull(uint32_t row, uint32_t column);
+
+    /**
+     * Gets the field slot at the specified row and column.
+     * Returns null if the requested row or column is not in the window.
+     */
+    FieldSlot* getFieldSlot(uint32_t row, uint32_t column);
+
+    inline int32_t getFieldSlotType(FieldSlot* fieldSlot) {
+        return fieldSlot->type;
+    }
+
+    inline int64_t getFieldSlotValueLong(FieldSlot* fieldSlot) {
         return fieldSlot->data.l;
-#else
-        return copyOutLong(fieldSlot->data.buffer.offset);
-#endif
     }
 
-    double getFieldSlotValueDouble(field_slot_t* fieldSlot) {
-#if WINDOW_STORAGE_INLINE_NUMERICS
+    inline double getFieldSlotValueDouble(FieldSlot* fieldSlot) {
         return fieldSlot->data.d;
-#else
-        return copyOutDouble(fieldSlot->data.buffer.offset);
-#endif
     }
 
-#if WINDOW_STORAGE_UTF8
-    char* getFieldSlotValueString(field_slot_t* fieldSlot) {
-        return reinterpret_cast<char*>(offsetToPtr(fieldSlot->data.buffer.offset));
+    inline const char* getFieldSlotValueString(FieldSlot* fieldSlot,
+            size_t* outSizeIncludingNull) {
+        *outSizeIncludingNull = fieldSlot->data.buffer.size;
+        return static_cast<char*>(offsetToPtr(fieldSlot->data.buffer.offset));
     }
-#else
-    char16_t* getFieldSlotValueString(field_slot_t* fieldSlot) {
-        return reinterpret_cast<char16_t*>(offsetToPtr(fieldSlot->data.buffer.offset));
+
+    inline const void* getFieldSlotValueBlob(FieldSlot* fieldSlot, size_t* outSize) {
+        *outSize = fieldSlot->data.buffer.size;
+        return offsetToPtr(fieldSlot->data.buffer.offset);
     }
-#endif
 
 private:
-    uint8_t * mData;
+    static const size_t ROW_SLOT_CHUNK_NUM_ROWS = 100;
+
+    struct Header {
+        // Offset of the lowest unused byte in the window.
+        uint32_t freeOffset;
+
+        // Offset of the first row slot chunk.
+        uint32_t firstChunkOffset;
+
+        uint32_t numRows;
+        uint32_t numColumns;
+    };
+
+    struct RowSlot {
+        uint32_t offset;
+    };
+
+    struct RowSlotChunk {
+        RowSlot slots[ROW_SLOT_CHUNK_NUM_ROWS];
+        uint32_t nextChunkOffset;
+    };
+
+    String8 mName;
+    int mAshmemFd;
+    void* mData;
     size_t mSize;
-    size_t mMaxSize;
-    window_header_t * mHeader;
-    sp<IMemory> mMemory;
+    bool mReadOnly;
+    Header* mHeader;
+
+    inline void* offsetToPtr(uint32_t offset) {
+        return static_cast<uint8_t*>(mData) + offset;
+    }
+
+    inline uint32_t offsetFromPtr(void* ptr) {
+        return static_cast<uint8_t*>(ptr) - static_cast<uint8_t*>(mData);
+    }
 
     /**
-     * Offset of the lowest unused data byte in the array.
+     * Allocate a portion of the window. Returns the offset
+     * of the allocation, or 0 if there isn't enough space.
+     * If aligned is true, the allocation gets 4 byte alignment.
      */
-    uint32_t mFreeOffset;
+    uint32_t alloc(size_t size, bool aligned = false);
+
+    RowSlot* getRowSlot(uint32_t row);
+    RowSlot* allocRowSlot();
+
+    status_t putBlobOrString(uint32_t row, uint32_t column,
+            const void* value, size_t size, int32_t type);
 };
 
 }; // namespace android