CursorWindow.cpp revision 9d3b1a424c5c61e24e9659d15fb353026a00d925 
1/*
2 * Copyright (C) 2006-2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#undef LOG_TAG
18#define LOG_TAG "CursorWindow"
19
20#include <androidfw/CursorWindow.h>
21#include <binder/Parcel.h>
22#include <utils/Log.h>
23
24#include <cutils/ashmem.h>
25#include <sys/mman.h>
26
27#include <assert.h>
28#include <string.h>
29#include <stdlib.h>
30
31namespace android {
32
33CursorWindow::CursorWindow(const String8& name, int ashmemFd,
34        void* data, size_t size, bool readOnly) :
35        mName(name), mAshmemFd(ashmemFd), mData(data), mSize(size), mReadOnly(readOnly) {
36    mHeader = static_cast<Header*>(mData);
37}
38
39CursorWindow::~CursorWindow() {
40    ::munmap(mData, mSize);
41    ::close(mAshmemFd);
42}
43
44status_t CursorWindow::create(const String8& name, size_t size, CursorWindow** outCursorWindow) {
45    String8 ashmemName("CursorWindow: ");
46    ashmemName.append(name);
47
48    status_t result;
49    int ashmemFd = ashmem_create_region(ashmemName.string(), size);
50    if (ashmemFd < 0) {
51        result = -errno;
52    } else {
53        result = ashmem_set_prot_region(ashmemFd, PROT_READ | PROT_WRITE);
54        if (result >= 0) {
55            void* data = ::mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, ashmemFd, 0);
56            if (data == MAP_FAILED) {
57                result = -errno;
58            } else {
59                result = ashmem_set_prot_region(ashmemFd, PROT_READ);
60                if (result >= 0) {
61                    CursorWindow* window = new CursorWindow(name, ashmemFd,
62                            data, size, false /*readOnly*/);
63                    result = window->clear();
64                    if (!result) {
65                        LOG_WINDOW("Created new CursorWindow: freeOffset=%d, "
66                                "numRows=%d, numColumns=%d, mSize=%d, mData=%p",
67                                window->mHeader->freeOffset,
68                                window->mHeader->numRows,
69                                window->mHeader->numColumns,
70                                window->mSize, window->mData);
71                        *outCursorWindow = window;
72                        return OK;
73                    }
74                    delete window;
75                }
76            }
77            ::munmap(data, size);
78        }
79        ::close(ashmemFd);
80    }
81    *outCursorWindow = NULL;
82    return result;
83}
84
85status_t CursorWindow::createFromParcel(Parcel* parcel, CursorWindow** outCursorWindow) {
86    String8 name = parcel->readString8();
87
88    status_t result;
89    int ashmemFd = parcel->readFileDescriptor();
90    if (ashmemFd == int(BAD_TYPE)) {
91        result = BAD_TYPE;
92    } else {
93        ssize_t size = ashmem_get_size_region(ashmemFd);
94        if (size < 0) {
95            result = UNKNOWN_ERROR;
96        } else {
97            int dupAshmemFd = ::dup(ashmemFd);
98            if (dupAshmemFd < 0) {
99                result = -errno;
100            } else {
101                void* data = ::mmap(NULL, size, PROT_READ, MAP_SHARED, dupAshmemFd, 0);
102                if (data == MAP_FAILED) {
103                    result = -errno;
104                } else {
105                    CursorWindow* window = new CursorWindow(name, dupAshmemFd,
106                            data, size, true /*readOnly*/);
107                    LOG_WINDOW("Created CursorWindow from parcel: freeOffset=%d, "
108                            "numRows=%d, numColumns=%d, mSize=%d, mData=%p",
109                            window->mHeader->freeOffset,
110                            window->mHeader->numRows,
111                            window->mHeader->numColumns,
112                            window->mSize, window->mData);
113                    *outCursorWindow = window;
114                    return OK;
115                }
116                ::close(dupAshmemFd);
117            }
118        }
119    }
120    *outCursorWindow = NULL;
121    return result;
122}
123
124status_t CursorWindow::writeToParcel(Parcel* parcel) {
125    status_t status = parcel->writeString8(mName);
126    if (!status) {
127        status = parcel->writeDupFileDescriptor(mAshmemFd);
128    }
129    return status;
130}
131
132status_t CursorWindow::clear() {
133    if (mReadOnly) {
134        return INVALID_OPERATION;
135    }
136
137    mHeader->freeOffset = sizeof(Header) + sizeof(RowSlotChunk);
138    mHeader->firstChunkOffset = sizeof(Header);
139    mHeader->numRows = 0;
140    mHeader->numColumns = 0;
141
142    RowSlotChunk* firstChunk = static_cast<RowSlotChunk*>(offsetToPtr(mHeader->firstChunkOffset));
143    firstChunk->nextChunkOffset = 0;
144    return OK;
145}
146
147status_t CursorWindow::setNumColumns(uint32_t numColumns) {
148    if (mReadOnly) {
149        return INVALID_OPERATION;
150    }
151
152    uint32_t cur = mHeader->numColumns;
153    if ((cur > 0 || mHeader->numRows > 0) && cur != numColumns) {
154        ALOGE("Trying to go from %d columns to %d", cur, numColumns);
155        return INVALID_OPERATION;
156    }
157    mHeader->numColumns = numColumns;
158    return OK;
159}
160
161status_t CursorWindow::allocRow() {
162    if (mReadOnly) {
163        return INVALID_OPERATION;
164    }
165
166    // Fill in the row slot
167    RowSlot* rowSlot = allocRowSlot();
168    if (rowSlot == NULL) {
169        return NO_MEMORY;
170    }
171
172    // Allocate the slots for the field directory
173    size_t fieldDirSize = mHeader->numColumns * sizeof(FieldSlot);
174    uint32_t fieldDirOffset = alloc(fieldDirSize, true /*aligned*/);
175    if (!fieldDirOffset) {
176        mHeader->numRows--;
177        LOG_WINDOW("The row failed, so back out the new row accounting "
178                "from allocRowSlot %d", mHeader->numRows);
179        return NO_MEMORY;
180    }
181    FieldSlot* fieldDir = static_cast<FieldSlot*>(offsetToPtr(fieldDirOffset));
182    memset(fieldDir, 0, fieldDirSize);
183
184    LOG_WINDOW("Allocated row %u, rowSlot is at offset %u, fieldDir is %d bytes at offset %u\n",
185            mHeader->numRows - 1, offsetFromPtr(rowSlot), fieldDirSize, fieldDirOffset);
186    rowSlot->offset = fieldDirOffset;
187    return OK;
188}
189
190status_t CursorWindow::freeLastRow() {
191    if (mReadOnly) {
192        return INVALID_OPERATION;
193    }
194
195    if (mHeader->numRows > 0) {
196        mHeader->numRows--;
197    }
198    return OK;
199}
200
201uint32_t CursorWindow::alloc(size_t size, bool aligned) {
202    uint32_t padding;
203    if (aligned) {
204        // 4 byte alignment
205        padding = (~mHeader->freeOffset + 1) & 3;
206    } else {
207        padding = 0;
208    }
209
210    uint32_t offset = mHeader->freeOffset + padding;
211    uint32_t nextFreeOffset = offset + size;
212    if (nextFreeOffset > mSize) {
213        ALOGW("Window is full: requested allocation %d bytes, "
214                "free space %d bytes, window size %d bytes",
215                size, freeSpace(), mSize);
216        return 0;
217    }
218
219    mHeader->freeOffset = nextFreeOffset;
220    return offset;
221}
222
223CursorWindow::RowSlot* CursorWindow::getRowSlot(uint32_t row) {
224    uint32_t chunkPos = row;
225    RowSlotChunk* chunk = static_cast<RowSlotChunk*>(
226            offsetToPtr(mHeader->firstChunkOffset));
227    while (chunkPos >= ROW_SLOT_CHUNK_NUM_ROWS) {
228        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
229        chunkPos -= ROW_SLOT_CHUNK_NUM_ROWS;
230    }
231    return &chunk->slots[chunkPos];
232}
233
234CursorWindow::RowSlot* CursorWindow::allocRowSlot() {
235    uint32_t chunkPos = mHeader->numRows;
236    RowSlotChunk* chunk = static_cast<RowSlotChunk*>(
237            offsetToPtr(mHeader->firstChunkOffset));
238    while (chunkPos > ROW_SLOT_CHUNK_NUM_ROWS) {
239        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
240        chunkPos -= ROW_SLOT_CHUNK_NUM_ROWS;
241    }
242    if (chunkPos == ROW_SLOT_CHUNK_NUM_ROWS) {
243        if (!chunk->nextChunkOffset) {
244            chunk->nextChunkOffset = alloc(sizeof(RowSlotChunk), true /*aligned*/);
245            if (!chunk->nextChunkOffset) {
246                return NULL;
247            }
248        }
249        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
250        chunk->nextChunkOffset = 0;
251        chunkPos = 0;
252    }
253    mHeader->numRows += 1;
254    return &chunk->slots[chunkPos];
255}
256
257CursorWindow::FieldSlot* CursorWindow::getFieldSlot(uint32_t row, uint32_t column) {
258    if (row >= mHeader->numRows || column >= mHeader->numColumns) {
259        ALOGE("Failed to read row %d, column %d from a CursorWindow which "
260                "has %d rows, %d columns.",
261                row, column, mHeader->numRows, mHeader->numColumns);
262        return NULL;
263    }
264    RowSlot* rowSlot = getRowSlot(row);
265    if (!rowSlot) {
266        ALOGE("Failed to find rowSlot for row %d.", row);
267        return NULL;
268    }
269    FieldSlot* fieldDir = static_cast<FieldSlot*>(offsetToPtr(rowSlot->offset));
270    return &fieldDir[column];
271}
272
273status_t CursorWindow::putBlob(uint32_t row, uint32_t column, const void* value, size_t size) {
274    return putBlobOrString(row, column, value, size, FIELD_TYPE_BLOB);
275}
276
277status_t CursorWindow::putString(uint32_t row, uint32_t column, const char* value,
278        size_t sizeIncludingNull) {
279    return putBlobOrString(row, column, value, sizeIncludingNull, FIELD_TYPE_STRING);
280}
281
282status_t CursorWindow::putBlobOrString(uint32_t row, uint32_t column,
283        const void* value, size_t size, int32_t type) {
284    if (mReadOnly) {
285        return INVALID_OPERATION;
286    }
287
288    FieldSlot* fieldSlot = getFieldSlot(row, column);
289    if (!fieldSlot) {
290        return BAD_VALUE;
291    }
292
293    uint32_t offset = alloc(size);
294    if (!offset) {
295        return NO_MEMORY;
296    }
297
298    memcpy(offsetToPtr(offset), value, size);
299
300    fieldSlot->type = type;
301    fieldSlot->data.buffer.offset = offset;
302    fieldSlot->data.buffer.size = size;
303    return OK;
304}
305
306status_t CursorWindow::putLong(uint32_t row, uint32_t column, int64_t value) {
307    if (mReadOnly) {
308        return INVALID_OPERATION;
309    }
310
311    FieldSlot* fieldSlot = getFieldSlot(row, column);
312    if (!fieldSlot) {
313        return BAD_VALUE;
314    }
315
316    fieldSlot->type = FIELD_TYPE_INTEGER;
317    fieldSlot->data.l = value;
318    return OK;
319}
320
321status_t CursorWindow::putDouble(uint32_t row, uint32_t column, double value) {
322    if (mReadOnly) {
323        return INVALID_OPERATION;
324    }
325
326    FieldSlot* fieldSlot = getFieldSlot(row, column);
327    if (!fieldSlot) {
328        return BAD_VALUE;
329    }
330
331    fieldSlot->type = FIELD_TYPE_FLOAT;
332    fieldSlot->data.d = value;
333    return OK;
334}
335
336status_t CursorWindow::putNull(uint32_t row, uint32_t column) {
337    if (mReadOnly) {
338        return INVALID_OPERATION;
339    }
340
341    FieldSlot* fieldSlot = getFieldSlot(row, column);
342    if (!fieldSlot) {
343        return BAD_VALUE;
344    }
345
346    fieldSlot->type = FIELD_TYPE_NULL;
347    fieldSlot->data.buffer.offset = 0;
348    fieldSlot->data.buffer.size = 0;
349    return OK;
350}
351
352}; // namespace android
353