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1 /*
2  * Copyright (C) 2006 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 "SqliteCursor.cpp"
19 
20 #include <jni.h>
21 #include <JNIHelp.h>
22 #include <android_runtime/AndroidRuntime.h>
23 
24 #include <sqlite3.h>
25 
26 #include <utils/Log.h>
27 
28 #include <stdio.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "binder/CursorWindow.h"
33 #include "sqlite3_exception.h"
34 
35 
36 namespace android {
37 
nativeFillWindow(JNIEnv * env,jclass clazz,jint databasePtr,jint statementPtr,jint windowPtr,jint startPos,jint offsetParam)38 static jint nativeFillWindow(JNIEnv* env, jclass clazz, jint databasePtr,
39         jint statementPtr, jint windowPtr, jint startPos, jint offsetParam) {
40     sqlite3* database = reinterpret_cast<sqlite3*>(databasePtr);
41     sqlite3_stmt* statement = reinterpret_cast<sqlite3_stmt*>(statementPtr);
42     CursorWindow* window = reinterpret_cast<CursorWindow*>(windowPtr);
43 
44     // Only do the binding if there is a valid offsetParam. If no binding needs to be done
45     // offsetParam will be set to 0, an invalid value.
46     if (offsetParam > 0) {
47         // Bind the offset parameter, telling the program which row to start with
48         int err = sqlite3_bind_int(statement, offsetParam, startPos);
49         if (err != SQLITE_OK) {
50             LOGE("Unable to bind offset position, offsetParam = %d", offsetParam);
51             throw_sqlite3_exception(env, database);
52             return 0;
53         }
54         LOG_WINDOW("Bound to startPos %d", startPos);
55     } else {
56         LOG_WINDOW("Not binding to startPos %d", startPos);
57     }
58 
59     // We assume numRows is initially 0.
60     LOG_WINDOW("Window: numRows = %d, size = %d, freeSpace = %d",
61             window->getNumRows(), window->size(), window->freeSpace());
62 
63     int numColumns = sqlite3_column_count(statement);
64     status_t status = window->setNumColumns(numColumns);
65     if (status) {
66         LOGE("Failed to change column count from %d to %d", window->getNumColumns(), numColumns);
67         jniThrowException(env, "java/lang/IllegalStateException", "numColumns mismatch");
68         return 0;
69     }
70 
71     int retryCount = 0;
72     int totalRows = 0;
73     int addedRows = 0;
74     bool windowFull = false;
75     bool gotException = false;
76     const bool countAllRows = (startPos == 0); // when startPos is 0, we count all rows
77     while (!gotException && (!windowFull || countAllRows)) {
78         int err = sqlite3_step(statement);
79         if (err == SQLITE_ROW) {
80             LOG_WINDOW("Stepped statement %p to row %d", statement, totalRows);
81             retryCount = 0;
82             totalRows += 1;
83 
84             // Skip the row if the window is full or we haven't reached the start position yet.
85             if (startPos >= totalRows || windowFull) {
86                 continue;
87             }
88 
89             // Allocate a new field directory for the row. This pointer is not reused
90             // since it may be possible for it to be relocated on a call to alloc() when
91             // the field data is being allocated.
92             status = window->allocRow();
93             if (status) {
94                 LOG_WINDOW("Failed allocating fieldDir at startPos %d row %d, error=%d",
95                         startPos, addedRows, status);
96                 windowFull = true;
97                 continue;
98             }
99 
100             // Pack the row into the window.
101             for (int i = 0; i < numColumns; i++) {
102                 int type = sqlite3_column_type(statement, i);
103                 if (type == SQLITE_TEXT) {
104                     // TEXT data
105                     const char* text = reinterpret_cast<const char*>(
106                             sqlite3_column_text(statement, i));
107                     // SQLite does not include the NULL terminator in size, but does
108                     // ensure all strings are NULL terminated, so increase size by
109                     // one to make sure we store the terminator.
110                     size_t sizeIncludingNull = sqlite3_column_bytes(statement, i) + 1;
111                     status = window->putString(addedRows, i, text, sizeIncludingNull);
112                     if (status) {
113                         LOG_WINDOW("Failed allocating %u bytes for text at %d,%d, error=%d",
114                                 sizeIncludingNull, startPos + addedRows, i, status);
115                         windowFull = true;
116                         break;
117                     }
118                     LOG_WINDOW("%d,%d is TEXT with %u bytes",
119                             startPos + addedRows, i, sizeIncludingNull);
120                 } else if (type == SQLITE_INTEGER) {
121                     // INTEGER data
122                     int64_t value = sqlite3_column_int64(statement, i);
123                     status = window->putLong(addedRows, i, value);
124                     if (status) {
125                         LOG_WINDOW("Failed allocating space for a long in column %d, error=%d",
126                                 i, status);
127                         windowFull = true;
128                         break;
129                     }
130                     LOG_WINDOW("%d,%d is INTEGER 0x%016llx", startPos + addedRows, i, value);
131                 } else if (type == SQLITE_FLOAT) {
132                     // FLOAT data
133                     double value = sqlite3_column_double(statement, i);
134                     status = window->putDouble(addedRows, i, value);
135                     if (status) {
136                         LOG_WINDOW("Failed allocating space for a double in column %d, error=%d",
137                                 i, status);
138                         windowFull = true;
139                         break;
140                     }
141                     LOG_WINDOW("%d,%d is FLOAT %lf", startPos + addedRows, i, value);
142                 } else if (type == SQLITE_BLOB) {
143                     // BLOB data
144                     const void* blob = sqlite3_column_blob(statement, i);
145                     size_t size = sqlite3_column_bytes(statement, i);
146                     status = window->putBlob(addedRows, i, blob, size);
147                     if (status) {
148                         LOG_WINDOW("Failed allocating %u bytes for blob at %d,%d, error=%d",
149                                 size, startPos + addedRows, i, status);
150                         windowFull = true;
151                         break;
152                     }
153                     LOG_WINDOW("%d,%d is Blob with %u bytes",
154                             startPos + addedRows, i, size);
155                 } else if (type == SQLITE_NULL) {
156                     // NULL field
157                     status = window->putNull(addedRows, i);
158                     if (status) {
159                         LOG_WINDOW("Failed allocating space for a null in column %d, error=%d",
160                                 i, status);
161                         windowFull = true;
162                         break;
163                     }
164 
165                     LOG_WINDOW("%d,%d is NULL", startPos + addedRows, i);
166                 } else {
167                     // Unknown data
168                     LOGE("Unknown column type when filling database window");
169                     throw_sqlite3_exception(env, "Unknown column type when filling window");
170                     gotException = true;
171                     break;
172                 }
173             }
174 
175             // Update the final row tally.
176             if (windowFull || gotException) {
177                 window->freeLastRow();
178             } else {
179                 addedRows += 1;
180             }
181         } else if (err == SQLITE_DONE) {
182             // All rows processed, bail
183             LOG_WINDOW("Processed all rows");
184             break;
185         } else if (err == SQLITE_LOCKED || err == SQLITE_BUSY) {
186             // The table is locked, retry
187             LOG_WINDOW("Database locked, retrying");
188             if (retryCount > 50) {
189                 LOGE("Bailing on database busy retry");
190                 throw_sqlite3_exception(env, database, "retrycount exceeded");
191                 gotException = true;
192             } else {
193                 // Sleep to give the thread holding the lock a chance to finish
194                 usleep(1000);
195                 retryCount++;
196             }
197         } else {
198             throw_sqlite3_exception(env, database);
199             gotException = true;
200         }
201     }
202 
203     LOG_WINDOW("Resetting statement %p after fetching %d rows and adding %d rows"
204             "to the window in %d bytes",
205             statement, totalRows, addedRows, window->size() - window->freeSpace());
206     sqlite3_reset(statement);
207 
208     // Report the total number of rows on request.
209     if (startPos > totalRows) {
210         LOGE("startPos %d > actual rows %d", startPos, totalRows);
211     }
212     return countAllRows ? totalRows : 0;
213 }
214 
nativeColumnCount(JNIEnv * env,jclass clazz,jint statementPtr)215 static jint nativeColumnCount(JNIEnv* env, jclass clazz, jint statementPtr) {
216     sqlite3_stmt* statement = reinterpret_cast<sqlite3_stmt*>(statementPtr);
217     return sqlite3_column_count(statement);
218 }
219 
nativeColumnName(JNIEnv * env,jclass clazz,jint statementPtr,jint columnIndex)220 static jstring nativeColumnName(JNIEnv* env, jclass clazz, jint statementPtr,
221         jint columnIndex) {
222     sqlite3_stmt* statement = reinterpret_cast<sqlite3_stmt*>(statementPtr);
223     const char* name = sqlite3_column_name(statement, columnIndex);
224     return env->NewStringUTF(name);
225 }
226 
227 
228 static JNINativeMethod sMethods[] =
229 {
230      /* name, signature, funcPtr */
231     { "nativeFillWindow", "(IIIII)I",
232             (void*)nativeFillWindow },
233     { "nativeColumnCount", "(I)I",
234             (void*)nativeColumnCount},
235     { "nativeColumnName", "(II)Ljava/lang/String;",
236             (void*)nativeColumnName},
237 };
238 
register_android_database_SQLiteQuery(JNIEnv * env)239 int register_android_database_SQLiteQuery(JNIEnv * env)
240 {
241     return AndroidRuntime::registerNativeMethods(env,
242         "android/database/sqlite/SQLiteQuery", sMethods, NELEM(sMethods));
243 }
244 
245 } // namespace android
246