CursorWindow.cpp revision 45e2e95c2ffeb2d978e2cce80b729ef6ada3b8d2 
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                // the size of the ashmem descriptor can be modified between ashmem_get_size_region
102                // call and mmap, so we'll check again immediately after memory is mapped
103                void* data = ::mmap(NULL, size, PROT_READ, MAP_SHARED, dupAshmemFd, 0);
104                if (data == MAP_FAILED) {
105                    result = -errno;
106                } else if (ashmem_get_size_region(dupAshmemFd) != size) {
107                    ::munmap(data, size);
108                    result = BAD_VALUE;
109                } else {
110                    CursorWindow* window = new CursorWindow(name, dupAshmemFd,
111                            data, size, true /*readOnly*/);
112                    LOG_WINDOW("Created CursorWindow from parcel: freeOffset=%d, "
113                            "numRows=%d, numColumns=%d, mSize=%d, mData=%p",
114                            window->mHeader->freeOffset,
115                            window->mHeader->numRows,
116                            window->mHeader->numColumns,
117                            window->mSize, window->mData);
118                    *outCursorWindow = window;
119                    return OK;
120                }
121                ::close(dupAshmemFd);
122            }
123        }
124    }
125    *outCursorWindow = NULL;
126    return result;
127}
128
129status_t CursorWindow::writeToParcel(Parcel* parcel) {
130    status_t status = parcel->writeString8(mName);
131    if (!status) {
132        status = parcel->writeDupFileDescriptor(mAshmemFd);
133    }
134    return status;
135}
136
137status_t CursorWindow::clear() {
138    if (mReadOnly) {
139        return INVALID_OPERATION;
140    }
141
142    mHeader->freeOffset = sizeof(Header) + sizeof(RowSlotChunk);
143    mHeader->firstChunkOffset = sizeof(Header);
144    mHeader->numRows = 0;
145    mHeader->numColumns = 0;
146
147    RowSlotChunk* firstChunk = static_cast<RowSlotChunk*>(offsetToPtr(mHeader->firstChunkOffset));
148    firstChunk->nextChunkOffset = 0;
149    return OK;
150}
151
152status_t CursorWindow::setNumColumns(uint32_t numColumns) {
153    if (mReadOnly) {
154        return INVALID_OPERATION;
155    }
156
157    uint32_t cur = mHeader->numColumns;
158    if ((cur > 0 || mHeader->numRows > 0) && cur != numColumns) {
159        ALOGE("Trying to go from %d columns to %d", cur, numColumns);
160        return INVALID_OPERATION;
161    }
162    mHeader->numColumns = numColumns;
163    return OK;
164}
165
166status_t CursorWindow::allocRow() {
167    if (mReadOnly) {
168        return INVALID_OPERATION;
169    }
170
171    // Fill in the row slot
172    RowSlot* rowSlot = allocRowSlot();
173    if (rowSlot == NULL) {
174        return NO_MEMORY;
175    }
176
177    // Allocate the slots for the field directory
178    size_t fieldDirSize = mHeader->numColumns * sizeof(FieldSlot);
179    uint32_t fieldDirOffset = alloc(fieldDirSize, true /*aligned*/);
180    if (!fieldDirOffset) {
181        mHeader->numRows--;
182        LOG_WINDOW("The row failed, so back out the new row accounting "
183                "from allocRowSlot %d", mHeader->numRows);
184        return NO_MEMORY;
185    }
186    FieldSlot* fieldDir = static_cast<FieldSlot*>(offsetToPtr(fieldDirOffset));
187    memset(fieldDir, 0, fieldDirSize);
188
189    LOG_WINDOW("Allocated row %u, rowSlot is at offset %u, fieldDir is %d bytes at offset %u\n",
190            mHeader->numRows - 1, offsetFromPtr(rowSlot), fieldDirSize, fieldDirOffset);
191    rowSlot->offset = fieldDirOffset;
192    return OK;
193}
194
195status_t CursorWindow::freeLastRow() {
196    if (mReadOnly) {
197        return INVALID_OPERATION;
198    }
199
200    if (mHeader->numRows > 0) {
201        mHeader->numRows--;
202    }
203    return OK;
204}
205
206uint32_t CursorWindow::alloc(size_t size, bool aligned) {
207    uint32_t padding;
208    if (aligned) {
209        // 4 byte alignment
210        padding = (~mHeader->freeOffset + 1) & 3;
211    } else {
212        padding = 0;
213    }
214
215    uint32_t offset = mHeader->freeOffset + padding;
216    uint32_t nextFreeOffset = offset + size;
217    if (nextFreeOffset > mSize) {
218        ALOGW("Window is full: requested allocation %zu bytes, "
219                "free space %zu bytes, window size %zu bytes",
220                size, freeSpace(), mSize);
221        return 0;
222    }
223
224    mHeader->freeOffset = nextFreeOffset;
225    return offset;
226}
227
228CursorWindow::RowSlot* CursorWindow::getRowSlot(uint32_t row) {
229    uint32_t chunkPos = row;
230    RowSlotChunk* chunk = static_cast<RowSlotChunk*>(
231            offsetToPtr(mHeader->firstChunkOffset));
232    while (chunkPos >= ROW_SLOT_CHUNK_NUM_ROWS) {
233        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
234        chunkPos -= ROW_SLOT_CHUNK_NUM_ROWS;
235    }
236    return &chunk->slots[chunkPos];
237}
238
239CursorWindow::RowSlot* CursorWindow::allocRowSlot() {
240    uint32_t chunkPos = mHeader->numRows;
241    RowSlotChunk* chunk = static_cast<RowSlotChunk*>(
242            offsetToPtr(mHeader->firstChunkOffset));
243    while (chunkPos > ROW_SLOT_CHUNK_NUM_ROWS) {
244        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
245        chunkPos -= ROW_SLOT_CHUNK_NUM_ROWS;
246    }
247    if (chunkPos == ROW_SLOT_CHUNK_NUM_ROWS) {
248        if (!chunk->nextChunkOffset) {
249            chunk->nextChunkOffset = alloc(sizeof(RowSlotChunk), true /*aligned*/);
250            if (!chunk->nextChunkOffset) {
251                return NULL;
252            }
253        }
254        chunk = static_cast<RowSlotChunk*>(offsetToPtr(chunk->nextChunkOffset));
255        chunk->nextChunkOffset = 0;
256        chunkPos = 0;
257    }
258    mHeader->numRows += 1;
259    return &chunk->slots[chunkPos];
260}
261
262CursorWindow::FieldSlot* CursorWindow::getFieldSlot(uint32_t row, uint32_t column) {
263    if (row >= mHeader->numRows || column >= mHeader->numColumns) {
264        ALOGE("Failed to read row %d, column %d from a CursorWindow which "
265                "has %d rows, %d columns.",
266                row, column, mHeader->numRows, mHeader->numColumns);
267        return NULL;
268    }
269    RowSlot* rowSlot = getRowSlot(row);
270    if (!rowSlot) {
271        ALOGE("Failed to find rowSlot for row %d.", row);
272        return NULL;
273    }
274    FieldSlot* fieldDir = static_cast<FieldSlot*>(offsetToPtr(rowSlot->offset));
275    return &fieldDir[column];
276}
277
278status_t CursorWindow::putBlob(uint32_t row, uint32_t column, const void* value, size_t size) {
279    return putBlobOrString(row, column, value, size, FIELD_TYPE_BLOB);
280}
281
282status_t CursorWindow::putString(uint32_t row, uint32_t column, const char* value,
283        size_t sizeIncludingNull) {
284    return putBlobOrString(row, column, value, sizeIncludingNull, FIELD_TYPE_STRING);
285}
286
287status_t CursorWindow::putBlobOrString(uint32_t row, uint32_t column,
288        const void* value, size_t size, int32_t type) {
289    if (mReadOnly) {
290        return INVALID_OPERATION;
291    }
292
293    FieldSlot* fieldSlot = getFieldSlot(row, column);
294    if (!fieldSlot) {
295        return BAD_VALUE;
296    }
297
298    uint32_t offset = alloc(size);
299    if (!offset) {
300        return NO_MEMORY;
301    }
302
303    memcpy(offsetToPtr(offset), value, size);
304
305    fieldSlot->type = type;
306    fieldSlot->data.buffer.offset = offset;
307    fieldSlot->data.buffer.size = size;
308    return OK;
309}
310
311status_t CursorWindow::putLong(uint32_t row, uint32_t column, int64_t value) {
312    if (mReadOnly) {
313        return INVALID_OPERATION;
314    }
315
316    FieldSlot* fieldSlot = getFieldSlot(row, column);
317    if (!fieldSlot) {
318        return BAD_VALUE;
319    }
320
321    fieldSlot->type = FIELD_TYPE_INTEGER;
322    fieldSlot->data.l = value;
323    return OK;
324}
325
326status_t CursorWindow::putDouble(uint32_t row, uint32_t column, double value) {
327    if (mReadOnly) {
328        return INVALID_OPERATION;
329    }
330
331    FieldSlot* fieldSlot = getFieldSlot(row, column);
332    if (!fieldSlot) {
333        return BAD_VALUE;
334    }
335
336    fieldSlot->type = FIELD_TYPE_FLOAT;
337    fieldSlot->data.d = value;
338    return OK;
339}
340
341status_t CursorWindow::putNull(uint32_t row, uint32_t column) {
342    if (mReadOnly) {
343        return INVALID_OPERATION;
344    }
345
346    FieldSlot* fieldSlot = getFieldSlot(row, column);
347    if (!fieldSlot) {
348        return BAD_VALUE;
349    }
350
351    fieldSlot->type = FIELD_TYPE_NULL;
352    fieldSlot->data.buffer.offset = 0;
353    fieldSlot->data.buffer.size = 0;
354    return OK;
355}
356
357}; // namespace android
358