yap-6.3/packages/myddas/sqlite3/Android/jni/sqlite/android_database_SQLiteConnection.cpp

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
** Modified to support SQLite extensions by the SQLite developers:
** sqlite-dev@sqlite.org.
*/

#define LOG_TAG "SQLiteConnection"

#include "ALog-priv.h"
#include <JNIHelp.h>
#include <jni.h>

#include <assert.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>

#if 0
#include <androidfw/CursorWindow.h>
#endif

#include <sqlite3.h>
#if 0
#include <sqlite3_android.h>
#endif

#include "android_database_SQLiteCommon.h"

#include <string>

// Set to 1 to use UTF16 storage for localized indexes.
#define UTF16_STORAGE 0

namespace android {

/* Busy timeout in milliseconds.
 * If another connection (possibly in another process) has the database locked
 * for
 * longer than this amount of time then SQLite will generate a SQLITE_BUSY
 * error.
 * The SQLITE_BUSY error is then raised as a SQLiteDatabaseLockedException.
 *
 * In ordinary usage, busy timeouts are quite rare.  Most databases only ever
 * have a single open connection at a time unless they are using WAL.  When
 * using
 * WAL, a timeout could occur if one connection is busy performing an
 * auto-checkpoint
 * operation.  The busy timeout needs to be long enough to tolerate slow I/O
 * write
 * operations but not so long as to cause the application to hang indefinitely
 * if
 * there is a problem acquiring a database lock.
 */
static const int BUSY_TIMEOUT_MS = 2500;

static JavaVM *gpJavaVM = 0;

static struct {
  jfieldID name;
  jfieldID numArgs;
  jmethodID dispatchCallback;
} gSQLiteCustomFunctionClassInfo;

static struct { jclass clazz; } gStringClassInfo;

struct SQLiteConnection {
  // Open flags.
  // Must be kept in sync with the constants defined in SQLiteDatabase.java.
  enum {
    OPEN_READWRITE = 0x00000000,
    OPEN_READONLY = 0x00000001,
    OPEN_READ_MASK = 0x00000001,
    NO_LOCALIZED_COLLATORS = 0x00000010,
    CREATE_IF_NECESSARY = 0x10000000,
  };

  sqlite3 *const db;
  const int openFlags;
  std::string path;
  std::string label;

  volatile bool canceled;

  SQLiteConnection(sqlite3 *db, int openFlags, const std::string &path,
                   const std::string &label)
      : db(db), openFlags(openFlags), path(path), label(label),
        canceled(false) {}
};

// Called each time a statement begins execution, when tracing is enabled.
static void sqliteTraceCallback(void *data, const char *sql) {
  SQLiteConnection *connection = static_cast<SQLiteConnection *>(data);
  ALOG(LOG_VERBOSE, SQLITE_TRACE_TAG, "%s: \"%s\"\n", connection->label.c_str(),
       sql);
}

// Called each time a statement finishes execution, when profiling is enabled.
static void sqliteProfileCallback(void *data, const char *sql,
                                  sqlite3_uint64 tm) {
  SQLiteConnection *connection = static_cast<SQLiteConnection *>(data);
  ALOG(LOG_VERBOSE, SQLITE_PROFILE_TAG, "%s: \"%s\" took %0.3f ms\n",
       connection->label.c_str(), sql, tm * 0.000001f);
}

// Called after each SQLite VM instruction when cancelation is enabled.
static int sqliteProgressHandlerCallback(void *data) {
  SQLiteConnection *connection = static_cast<SQLiteConnection *>(data);
  return connection->canceled;
}

/*
** This function is a collation sequence callback equivalent to the built-in
** BINARY sequence.
**
** Stock Android uses a modified version of sqlite3.c that calls out to a module
** named "sqlite3_android" to add extra built-in collations and functions to
** all database handles. Specifically, collation sequence "LOCALIZED". For now,
** this module does not include sqlite3_android (since it is difficult to build
** with the NDK only). Instead, this function is registered as "LOCALIZED" for
*all
** new database handles.
*/
static int coll_localized(void *not_used, int nKey1, const void *pKey1,
                          int nKey2, const void *pKey2) {
  int rc, n;
  n = nKey1 < nKey2 ? nKey1 : nKey2;
  rc = memcmp(pKey1, pKey2, n);
  if (rc == 0) {
    rc = nKey1 - nKey2;
  }
  return rc;
}

static jlong nativeOpen(JNIEnv *env, jclass clazz, jstring pathStr,
                        jint openFlags, jstring labelStr, jboolean enableTrace,
                        jboolean enableProfile) {
  int sqliteFlags;
  if (openFlags & SQLiteConnection::CREATE_IF_NECESSARY) {
    sqliteFlags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
  } else if (openFlags & SQLiteConnection::OPEN_READONLY) {
    sqliteFlags = SQLITE_OPEN_READONLY;
  } else {
    sqliteFlags = SQLITE_OPEN_READWRITE;
  }

  const char *pathChars = env->GetStringUTFChars(pathStr, NULL);
  std::string path(pathChars);
  env->ReleaseStringUTFChars(pathStr, pathChars);

  const char *labelChars = env->GetStringUTFChars(labelStr, NULL);
  std::string label(labelChars);
  env->ReleaseStringUTFChars(labelStr, labelChars);

  sqlite3 *db;
  int err = sqlite3_open_v2(path.c_str(), &db, sqliteFlags, NULL);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception_errcode(env, err, "Could not open database");
    return 0;
  }
  err =
      sqlite3_create_collation(db, "localized", SQLITE_UTF8, 0, coll_localized);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception_errcode(env, err, "Could not register collation");
    sqlite3_close(db);
    return 0;
  }

  // Check that the database is really read/write when that is what we asked
  // for.
  if ((sqliteFlags & SQLITE_OPEN_READWRITE) && sqlite3_db_readonly(db, NULL)) {
    throw_sqlite3_exception(env, db,
                            "Could not open the database in read/write mode.");
    sqlite3_close(db);
    return 0;
  }

  // Set the default busy handler to retry automatically before returning
  // SQLITE_BUSY.
  err = sqlite3_busy_timeout(db, BUSY_TIMEOUT_MS);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, db, "Could not set busy timeout");
    sqlite3_close(db);
    return 0;
  }

// Register custom Android functions.
#if 0
    err = register_android_functions(db, UTF16_STORAGE);
    if (err) {
        throw_sqlite3_exception(env, db, "Could not register Android SQL functions.");
        sqlite3_close(db);
        return 0;
    }
#endif

  // Create wrapper object.
  SQLiteConnection *connection =
      new SQLiteConnection(db, openFlags, path, label);

  // Enable tracing and profiling if requested.
  if (enableTrace) {
    sqlite3_trace(db, &sqliteTraceCallback, connection);
  }
  if (enableProfile) {
    sqlite3_profile(db, &sqliteProfileCallback, connection);
  }

  ALOGV("Opened connection %p with label '%s'", db, label.c_str());
  return reinterpret_cast<jlong>(connection);
}

static void nativeClose(JNIEnv *env, jclass clazz, jlong connectionPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);

  if (connection) {
    ALOGV("Closing connection %p", connection->db);
    int err = sqlite3_close(connection->db);
    if (err != SQLITE_OK) {
      // This can happen if sub-objects aren't closed first.  Make sure the
      // caller knows.
      ALOGE("sqlite3_close(%p) failed: %d", connection->db, err);
      throw_sqlite3_exception(env, connection->db, "Count not close db.");
      return;
    }

    delete connection;
  }
}

// Called each time a custom function is evaluated.
static void sqliteCustomFunctionCallback(sqlite3_context *context, int argc,
                                         sqlite3_value **argv) {

  JNIEnv *env = 0;
  gpJavaVM->GetEnv((void **)&env, JNI_VERSION_1_4);

  // Get the callback function object.
  // Create a new local reference to it in case the callback tries to do
  // something
  // dumb like unregister the function (thereby destroying the global ref) while
  // it is running.
  jobject functionObjGlobal =
      reinterpret_cast<jobject>(sqlite3_user_data(context));
  jobject functionObj = env->NewLocalRef(functionObjGlobal);

  jobjectArray argsArray =
      env->NewObjectArray(argc, gStringClassInfo.clazz, NULL);
  if (argsArray) {
    for (int i = 0; i < argc; i++) {
      const jchar *arg =
          static_cast<const jchar *>(sqlite3_value_text16(argv[i]));
      if (!arg) {
        ALOGW("NULL argument in custom_function_callback.  This should not "
              "happen.");
      } else {
        size_t argLen = sqlite3_value_bytes16(argv[i]) / sizeof(jchar);
        jstring argStr = env->NewString(arg, argLen);
        if (!argStr) {
          goto error; // out of memory error
        }
        env->SetObjectArrayElement(argsArray, i, argStr);
        env->DeleteLocalRef(argStr);
      }
    }

    // TODO: Support functions that return values.
    env->CallVoidMethod(functionObj,
                        gSQLiteCustomFunctionClassInfo.dispatchCallback,
                        argsArray);

  error:
    env->DeleteLocalRef(argsArray);
  }

  env->DeleteLocalRef(functionObj);

  if (env->ExceptionCheck()) {
    ALOGE("An exception was thrown by custom SQLite function.");
    /* LOGE_EX(env); */
    env->ExceptionClear();
  }
}

// Called when a custom function is destroyed.
static void sqliteCustomFunctionDestructor(void *data) {
  jobject functionObjGlobal = reinterpret_cast<jobject>(data);
  JNIEnv *env = 0;
  gpJavaVM->GetEnv((void **)&env, JNI_VERSION_1_4);
  env->DeleteGlobalRef(functionObjGlobal);
}

static void nativeRegisterCustomFunction(JNIEnv *env, jclass clazz,
                                         jlong connectionPtr,
                                         jobject functionObj) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);

  jstring nameStr = jstring(
      env->GetObjectField(functionObj, gSQLiteCustomFunctionClassInfo.name));
  jint numArgs =
      env->GetIntField(functionObj, gSQLiteCustomFunctionClassInfo.numArgs);

  jobject functionObjGlobal = env->NewGlobalRef(functionObj);

  const char *name = env->GetStringUTFChars(nameStr, NULL);
  int err =
      sqlite3_create_function_v2(connection->db, name, numArgs, SQLITE_UTF16,
                                 reinterpret_cast<void *>(functionObjGlobal),
                                 &sqliteCustomFunctionCallback, NULL, NULL,
                                 &sqliteCustomFunctionDestructor);
  env->ReleaseStringUTFChars(nameStr, name);

  if (err != SQLITE_OK) {
    ALOGE("sqlite3_create_function returned %d", err);
    env->DeleteGlobalRef(functionObjGlobal);
    throw_sqlite3_exception(env, connection->db);
    return;
  }
}

static void nativeRegisterLocalizedCollators(JNIEnv *env, jclass clazz,
                                             jlong connectionPtr,
                                             jstring localeStr) {
#if 0
    SQLiteConnection* connection = reinterpret_cast<SQLiteConnection*>(connectionPtr);

    const char* locale = env->GetStringUTFChars(localeStr, NULL);
    int err = register_localized_collators(connection->db, locale, UTF16_STORAGE);
    env->ReleaseStringUTFChars(localeStr, locale);

    if (err != SQLITE_OK) {
        throw_sqlite3_exception(env, connection->db);
    }
#endif
}

static jlong nativePrepareStatement(JNIEnv *env, jclass clazz,
                                    jlong connectionPtr, jstring sqlString) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);

  jsize sqlLength = env->GetStringLength(sqlString);
  const jchar *sql = env->GetStringCritical(sqlString, NULL);
  sqlite3_stmt *statement;
  int err = sqlite3_prepare16_v2(connection->db, sql, sqlLength * sizeof(jchar),
                                 &statement, NULL);
  env->ReleaseStringCritical(sqlString, sql);

  if (err != SQLITE_OK) {
    // Error messages like 'near ")": syntax error' are not
    // always helpful enough, so construct an error string that
    // includes the query itself.
    const char *query = env->GetStringUTFChars(sqlString, NULL);
    char *message = (char *)malloc(strlen(query) + 50);
    if (message) {
      strcpy(message, ", while compiling: "); // less than 50 chars
      strcat(message, query);
    }
    env->ReleaseStringUTFChars(sqlString, query);
    throw_sqlite3_exception(env, connection->db, message);
    free(message);
    return 0;
  }

  ALOGV("Prepared statement %p on connection %p", statement, connection->db);
  return reinterpret_cast<jlong>(statement);
}

static void nativeFinalizeStatement(JNIEnv *env, jclass clazz,
                                    jlong connectionPtr, jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  // We ignore the result of sqlite3_finalize because it is really telling us
  // about
  // whether any errors occurred while executing the statement.  The statement
  // itself
  // is always finalized regardless.
  ALOGV("Finalized statement %p on connection %p", statement, connection->db);
  sqlite3_finalize(statement);
}

static jint nativeGetParameterCount(JNIEnv *env, jclass clazz,
                                    jlong connectionPtr, jlong statementPtr) {
  // SQLiteConnection *connection =
  //    reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  return sqlite3_bind_parameter_count(statement);
}

static jboolean nativeIsReadOnly(JNIEnv *env, jclass clazz, jlong connectionPtr,
                                 jlong statementPtr) {
  // SQLiteConnection *connection =
  //    reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  return sqlite3_stmt_readonly(statement) != 0;
}

static jint nativeGetColumnCount(JNIEnv *env, jclass clazz, jlong connectionPtr,
                                 jlong statementPtr) {
  // SQLiteConnection *connection =
  //    reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  return sqlite3_column_count(statement);
}

static jstring nativeGetColumnName(JNIEnv *env, jclass clazz,
                                   jlong connectionPtr, jlong statementPtr,
                                   jint index) {
  // SQLiteConnection *connection =
  //    reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  const jchar *name =
      static_cast<const jchar *>(sqlite3_column_name16(statement, index));
  if (name) {
    size_t length = 0;
    while (name[length]) {
      length += 1;
    }
    return env->NewString(name, length);
  }
  return NULL;
}

static void nativeBindNull(JNIEnv *env, jclass clazz, jlong connectionPtr,
                           jlong statementPtr, jint index) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = sqlite3_bind_null(statement, index);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static void nativeBindLong(JNIEnv *env, jclass clazz, jlong connectionPtr,
                           jlong statementPtr, jint index, jlong value) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = sqlite3_bind_int64(statement, index, value);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static void nativeBindDouble(JNIEnv *env, jclass clazz, jlong connectionPtr,
                             jlong statementPtr, jint index, jdouble value) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = sqlite3_bind_double(statement, index, value);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static void nativeBindString(JNIEnv *env, jclass clazz, jlong connectionPtr,
                             jlong statementPtr, jint index,
                             jstring valueString) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  jsize valueLength = env->GetStringLength(valueString);
  const jchar *value = env->GetStringCritical(valueString, NULL);
  int err = sqlite3_bind_text16(statement, index, value,
                                valueLength * sizeof(jchar), SQLITE_TRANSIENT);
  env->ReleaseStringCritical(valueString, value);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static void nativeBindBlob(JNIEnv *env, jclass clazz, jlong connectionPtr,
                           jlong statementPtr, jint index,
                           jbyteArray valueArray) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  jsize valueLength = env->GetArrayLength(valueArray);
  jbyte *value =
      static_cast<jbyte *>(env->GetPrimitiveArrayCritical(valueArray, NULL));
  int err =
      sqlite3_bind_blob(statement, index, value, valueLength, SQLITE_TRANSIENT);
  env->ReleasePrimitiveArrayCritical(valueArray, value, JNI_ABORT);
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static void nativeResetStatementAndClearBindings(JNIEnv *env, jclass clazz,
                                                 jlong connectionPtr,
                                                 jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = sqlite3_reset(statement);
  if (err == SQLITE_OK) {
    err = sqlite3_clear_bindings(statement);
  }
  if (err != SQLITE_OK) {
    throw_sqlite3_exception(env, connection->db, NULL);
  }
}

static int executeNonQuery(JNIEnv *env, SQLiteConnection *connection,
                           sqlite3_stmt *statement) {
  int err = sqlite3_step(statement);
  if (err == SQLITE_ROW) {
    throw_sqlite3_exception(env, "Queries can be performed using "
                                 "SQLiteDatabase query or rawQuery methods "
                                 "only.");
  } else if (err != SQLITE_DONE) {
    throw_sqlite3_exception(env, connection->db);
  }
  return err;
}

static void nativeExecute(JNIEnv *env, jclass clazz, jlong connectionPtr,
                          jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  executeNonQuery(env, connection, statement);
}

static jint nativeExecuteForChangedRowCount(JNIEnv *env, jclass clazz,
                                            jlong connectionPtr,
                                            jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = executeNonQuery(env, connection, statement);
  return err == SQLITE_DONE ? sqlite3_changes(connection->db) : -1;
}

static jlong nativeExecuteForLastInsertedRowId(JNIEnv *env, jclass clazz,
                                               jlong connectionPtr,
                                               jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = executeNonQuery(env, connection, statement);
  return err == SQLITE_DONE && sqlite3_changes(connection->db) > 0
             ? sqlite3_last_insert_rowid(connection->db)
             : -1;
}

static int executeOneRowQuery(JNIEnv *env, SQLiteConnection *connection,
                              sqlite3_stmt *statement) {
  int err = sqlite3_step(statement);
  if (err != SQLITE_ROW) {
    throw_sqlite3_exception(env, connection->db);
  }
  return err;
}

static jlong nativeExecuteForLong(JNIEnv *env, jclass clazz,
                                  jlong connectionPtr, jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = executeOneRowQuery(env, connection, statement);
  if (err == SQLITE_ROW && sqlite3_column_count(statement) >= 1) {
    return sqlite3_column_int64(statement, 0);
  }
  return -1;
}

static jstring nativeExecuteForString(JNIEnv *env, jclass clazz,
                                      jlong connectionPtr, jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = executeOneRowQuery(env, connection, statement);
  if (err == SQLITE_ROW && sqlite3_column_count(statement) >= 1) {
    const jchar *text =
        static_cast<const jchar *>(sqlite3_column_text16(statement, 0));
    if (text) {
      size_t length = sqlite3_column_bytes16(statement, 0) / sizeof(jchar);
      return env->NewString(text, length);
    }
  }
  return NULL;
}

static int createAshmemRegionWithData(JNIEnv *env, const void *data,
                                      size_t length) {
#if 0
    int error = 0;
    int fd = ashmem_create_region(NULL, length);
    if (fd < 0) {
        error = errno;
        ALOGE("ashmem_create_region failed: %s", strerror(error));
    } else {
        if (length > 0) {
            void* ptr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
            if (ptr == MAP_FAILED) {
                error = errno;
                ALOGE("mmap failed: %s", strerror(error));
            } else {
                memcpy(ptr, data, length);
                munmap(ptr, length);
            }
        }

        if (!error) {
            if (ashmem_set_prot_region(fd, PROT_READ) < 0) {
                error = errno;
                ALOGE("ashmem_set_prot_region failed: %s", strerror(errno));
            } else {
                return fd;
            }
        }

        close(fd);
    }

#endif
  jniThrowIOException(env, -1);
  return -1;
}

static jint nativeExecuteForBlobFileDescriptor(JNIEnv *env, jclass clazz,
                                               jlong connectionPtr,
                                               jlong statementPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *statement = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  int err = executeOneRowQuery(env, connection, statement);
  if (err == SQLITE_ROW && sqlite3_column_count(statement) >= 1) {
    const void *blob = sqlite3_column_blob(statement, 0);
    if (blob) {
      int length = sqlite3_column_bytes(statement, 0);
      if (length >= 0) {
        return createAshmemRegionWithData(env, blob, length);
      }
    }
  }
  return -1;
}

/*
** Note: The following symbols must be in the same order as the corresponding
** elements in the aMethod[] array in function nativeExecuteForCursorWindow().
*/
enum CWMethodNames {
  CW_CLEAR = 0,
  CW_SETNUMCOLUMNS = 1,
  CW_ALLOCROW = 2,
  CW_FREELASTROW = 3,
  CW_PUTNULL = 4,
  CW_PUTLONG = 5,
  CW_PUTDOUBLE = 6,
  CW_PUTSTRING = 7,
  CW_PUTBLOB = 8
};

/*
** An instance of this structure represents a single CursorWindow java method.
*/
struct CWMethod {
  jmethodID id;      /* Method id */
  const char *zName; /* Method name */
  const char *zSig;  /* Method JNI signature */
};

/*
** Append the contents of the row that SQL statement pStmt currently points to
** to the CursorWindow object passed as the second argument. The CursorWindow
** currently contains iRow rows. Return true on success or false if an error
** occurs.
*/
static jboolean copyRowToWindow(JNIEnv *pEnv, jobject win, int iRow,
                                sqlite3_stmt *pStmt, CWMethod *aMethod) {
  int nCol = sqlite3_column_count(pStmt);
  int i;
  jboolean bOk;

  bOk = pEnv->CallBooleanMethod(win, aMethod[CW_ALLOCROW].id);
  for (i = 0; bOk && i < nCol; i++) {
    switch (sqlite3_column_type(pStmt, i)) {
    case SQLITE_NULL: {
      bOk = pEnv->CallBooleanMethod(win, aMethod[CW_PUTNULL].id, iRow, i);
      break;
    }

    case SQLITE_INTEGER: {
      jlong val = sqlite3_column_int64(pStmt, i);
      bOk = pEnv->CallBooleanMethod(win, aMethod[CW_PUTLONG].id, val, iRow, i);
      break;
    }

    case SQLITE_FLOAT: {
      jdouble val = sqlite3_column_double(pStmt, i);
      bOk =
          pEnv->CallBooleanMethod(win, aMethod[CW_PUTDOUBLE].id, val, iRow, i);
      break;
    }

    case SQLITE_TEXT: {
      jchar *pStr = (jchar *)sqlite3_column_text16(pStmt, i);
      int nStr = sqlite3_column_bytes16(pStmt, i) / sizeof(jchar);
      jstring val = pEnv->NewString(pStr, nStr);
      bOk =
          pEnv->CallBooleanMethod(win, aMethod[CW_PUTSTRING].id, val, iRow, i);
      pEnv->DeleteLocalRef(val);
      break;
    }

    default: {
      assert(sqlite3_column_type(pStmt, i) == SQLITE_BLOB);
      const jbyte *p = (const jbyte *)sqlite3_column_blob(pStmt, i);
      int n = sqlite3_column_bytes(pStmt, i);
      jbyteArray val = pEnv->NewByteArray(n);
      pEnv->SetByteArrayRegion(val, 0, n, p);
      bOk = pEnv->CallBooleanMethod(win, aMethod[CW_PUTBLOB].id, val, iRow, i);
      pEnv->DeleteLocalRef(val);
      break;
    }
    }

    if (bOk == 0) {
      pEnv->CallVoidMethod(win, aMethod[CW_FREELASTROW].id);
    }
  }

  return bOk;
}

static jboolean setWindowNumColumns(JNIEnv *pEnv, jobject win,
                                    sqlite3_stmt *pStmt, CWMethod *aMethod) {
  int nCol;

  pEnv->CallVoidMethod(win, aMethod[CW_CLEAR].id);
  nCol = sqlite3_column_count(pStmt);
  return pEnv->CallBooleanMethod(win, aMethod[CW_SETNUMCOLUMNS].id, (jint)nCol);
}

/*
** This method has been rewritten for org.sqlite.database.*. The original
** android implementation used the C++ interface to populate a CursorWindow
** object. Since the NDK does not export this interface, we invoke the Java
** interface using standard JNI methods to do the same thing.
**
** This function executes the SQLite statement object passed as the 4th
** argument and copies one or more returned rows into the CursorWindow
** object passed as the 5th argument. The set of rows copied into the
** CursorWindow is always contiguous.
**
** The only row that *must* be copied into the CursorWindow is row
** iRowRequired. Ideally, all rows from iRowStart through to the end
** of the query are copied into the CursorWindow. If this is not possible
** (CursorWindow objects have a finite capacity), some compromise position
** is found (see comments embedded in the code below for details).
**
** The return value is a 64-bit integer calculated as follows:
**
**      (iStart << 32) | nRow
**
** where iStart is the index of the first row copied into the CursorWindow.
** If the countAllRows argument is true, nRow is the total number of rows
** returned by the query. Otherwise, nRow is one greater than the index of
** the last row copied into the CursorWindow.
*/
static jlong nativeExecuteForCursorWindow(
    JNIEnv *pEnv, jclass clazz,
    jlong connectionPtr, /* Pointer to SQLiteConnection C++ object */
    jlong statementPtr,  /* Pointer to sqlite3_stmt object */
    jobject win,         /* The CursorWindow object to populate */
    jint startPos,       /* First row to add (advisory) */
    jint iRowRequired,   /* Required row */
    jboolean countAllRows) {
  // SQLiteConnection *pConnection =
  //    reinterpret_cast<SQLiteConnection *>(connectionPtr);
  sqlite3_stmt *pStmt = reinterpret_cast<sqlite3_stmt *>(statementPtr);

  CWMethod aMethod[] = {
      {0, "clear", "()V"},        {0, "setNumColumns", "(I)Z"},
      {0, "allocRow", "()Z"},     {0, "freeLastRow", "()V"},
      {0, "putNull", "(II)Z"},    {0, "putLong", "(JII)Z"},
      {0, "putDouble", "(DII)Z"}, {0, "putString", "(Ljava/lang/String;II)Z"},
      {0, "putBlob", "([BII)Z"},
  };
  jclass cls;     /* Class android.database.CursorWindow */
  unsigned int i; /* Iterator variable */
  // int nCol;       /* Number of columns returned by pStmt */
  int nRow;
  jboolean bOk;
  int iStart; /* First row copied to CursorWindow */

  /* Locate all required CursorWindow methods. */
  cls = pEnv->FindClass("android/database/CursorWindow");
  for (i = 0; i < (sizeof(aMethod) / sizeof(struct CWMethod)); i++) {
    aMethod[i].id = pEnv->GetMethodID(cls, aMethod[i].zName, aMethod[i].zSig);
    if (aMethod[i].id == NULL) {
      jniThrowExceptionFmt(pEnv, "java/lang/Exception",
                           "Failed to find method CursorWindow.%s()",
                           aMethod[i].zName);
      return 0;
    }
  }

  /* Set the number of columns in the window */
  bOk = setWindowNumColumns(pEnv, win, pStmt, aMethod);
  if (bOk == 0)
    return 0;

  nRow = 0;
  iStart = startPos;
  while (sqlite3_step(pStmt) == SQLITE_ROW) {
    /* Only copy in rows that occur at or after row index iStart. */
    if (nRow >= iStart && bOk) {
      bOk = copyRowToWindow(pEnv, win, (nRow - iStart), pStmt, aMethod);
      if (bOk == 0) {
        /* The CursorWindow object ran out of memory. If row iRowRequired was
        ** not successfully added before this happened, clear the CursorWindow
        ** and try to add the current row again.  */
        if (nRow <= iRowRequired) {
          bOk = setWindowNumColumns(pEnv, win, pStmt, aMethod);
          if (bOk == 0) {
            sqlite3_reset(pStmt);
            return 0;
          }
          iStart = nRow;
          bOk = copyRowToWindow(pEnv, win, (nRow - iStart), pStmt, aMethod);
        }

        /* If the CursorWindow is still full and the countAllRows flag is not
        ** set, break out of the loop here. If countAllRows is set, continue
        ** so as to set variable nRow correctly.  */
        if (bOk == 0 && countAllRows == 0)
          break;
      }
    }

    nRow++;
  }

  /* Finalize the statement. If this indicates an error occurred, throw an
  ** SQLiteException exception.  */
  int rc = sqlite3_reset(pStmt);
  if (rc != SQLITE_OK) {
    throw_sqlite3_exception(pEnv, sqlite3_db_handle(pStmt));
    return 0;
  }

  jlong lRet = jlong(iStart) << 32 | jlong(nRow);
  return lRet;
}

static jint nativeGetDbLookaside(JNIEnv *env, jobject clazz,
                                 jlong connectionPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);

  int cur = -1;
  int unused;
  sqlite3_db_status(connection->db, SQLITE_DBSTATUS_LOOKASIDE_USED, &cur,
                    &unused, 0);
  return cur;
}

static void nativeCancel(JNIEnv *env, jobject clazz, jlong connectionPtr) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  connection->canceled = true;
}

static void nativeResetCancel(JNIEnv *env, jobject clazz, jlong connectionPtr,
                              jboolean cancelable) {
  SQLiteConnection *connection =
      reinterpret_cast<SQLiteConnection *>(connectionPtr);
  connection->canceled = false;

  if (cancelable) {
    sqlite3_progress_handler(connection->db, 4, sqliteProgressHandlerCallback,
                             connection);
  } else {
    sqlite3_progress_handler(connection->db, 0, NULL, NULL);
  }
}

static jboolean nativeHasCodec(JNIEnv *env, jobject clazz) {
#ifdef SQLITE_HAS_CODEC
  return true;
#else
  return false;
#endif
}

static JNINativeMethod sMethods[] = {
    /* name, signature, funcPtr */
    {"nativeOpen", "(Ljava/lang/String;ILjava/lang/String;ZZ)J",
     (void *)nativeOpen},
    {"nativeClose", "(J)V", (void *)nativeClose},
    {"nativeRegisterCustomFunction",
     "(JLorg/sqlite/database/sqlite/SQLiteCustomFunction;)V",
     (void *)nativeRegisterCustomFunction},
    {"nativeRegisterLocalizedCollators", "(JLjava/lang/String;)V",
     (void *)nativeRegisterLocalizedCollators},
    {"nativePrepareStatement", "(JLjava/lang/String;)J",
     (void *)nativePrepareStatement},
    {"nativeFinalizeStatement", "(JJ)V", (void *)nativeFinalizeStatement},
    {"nativeGetParameterCount", "(JJ)I", (void *)nativeGetParameterCount},
    {"nativeIsReadOnly", "(JJ)Z", (void *)nativeIsReadOnly},
    {"nativeGetColumnCount", "(JJ)I", (void *)nativeGetColumnCount},
    {"nativeGetColumnName", "(JJI)Ljava/lang/String;",
     (void *)nativeGetColumnName},
    {"nativeBindNull", "(JJI)V", (void *)nativeBindNull},
    {"nativeBindLong", "(JJIJ)V", (void *)nativeBindLong},
    {"nativeBindDouble", "(JJID)V", (void *)nativeBindDouble},
    {"nativeBindString", "(JJILjava/lang/String;)V", (void *)nativeBindString},
    {"nativeBindBlob", "(JJI[B)V", (void *)nativeBindBlob},
    {"nativeResetStatementAndClearBindings", "(JJ)V",
     (void *)nativeResetStatementAndClearBindings},
    {"nativeExecute", "(JJ)V", (void *)nativeExecute},
    {"nativeExecuteForLong", "(JJ)J", (void *)nativeExecuteForLong},
    {"nativeExecuteForString", "(JJ)Ljava/lang/String;",
     (void *)nativeExecuteForString},
    {"nativeExecuteForBlobFileDescriptor", "(JJ)I",
     (void *)nativeExecuteForBlobFileDescriptor},
    {"nativeExecuteForChangedRowCount", "(JJ)I",
     (void *)nativeExecuteForChangedRowCount},
    {"nativeExecuteForLastInsertedRowId", "(JJ)J",
     (void *)nativeExecuteForLastInsertedRowId},
    {"nativeExecuteForCursorWindow", "(JJLandroid/database/CursorWindow;IIZ)J",
     (void *)nativeExecuteForCursorWindow},
    {"nativeGetDbLookaside", "(J)I", (void *)nativeGetDbLookaside},
    {"nativeCancel", "(J)V", (void *)nativeCancel},
    {"nativeResetCancel", "(JZ)V", (void *)nativeResetCancel},

    {"nativeHasCodec", "()Z", (void *)nativeHasCodec},
};

#define FIND_CLASS(var, className)                                             \
  var = env->FindClass(className);                                             \
  LOG_FATAL_IF(!var, "Unable to find class " className);

#define GET_METHOD_ID(var, clazz, methodName, fieldDescriptor)                 \
  var = env->GetMethodID(clazz, methodName, fieldDescriptor);                  \
  LOG_FATAL_IF(!var, "Unable to find method" methodName);

#define GET_FIELD_ID(var, clazz, fieldName, fieldDescriptor)                   \
  var = env->GetFieldID(clazz, fieldName, fieldDescriptor);                    \
  LOG_FATAL_IF(!var, "Unable to find field " fieldName);

int register_android_database_SQLiteConnection(JNIEnv *env) {
  jclass clazz;
  FIND_CLASS(clazz, "org/sqlite/database/sqlite/SQLiteCustomFunction");

  GET_FIELD_ID(gSQLiteCustomFunctionClassInfo.name, clazz, "name",
               "Ljava/lang/String;");
  GET_FIELD_ID(gSQLiteCustomFunctionClassInfo.numArgs, clazz, "numArgs", "I");
  GET_METHOD_ID(gSQLiteCustomFunctionClassInfo.dispatchCallback, clazz,
                "dispatchCallback", "([Ljava/lang/String;)V");

  FIND_CLASS(clazz, "java/lang/String");
  gStringClassInfo.clazz = jclass(env->NewGlobalRef(clazz));

  return jniRegisterNativeMethods(env,
                                  "org/sqlite/database/sqlite/SQLiteConnection",
                                  sMethods, NELEM(sMethods));
}

extern int register_android_database_SQLiteGlobal(JNIEnv *env);
extern int register_android_database_SQLiteDebug(JNIEnv *env);

} // namespace android

extern "C" JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved) {
  JNIEnv *env = 0;

  android::gpJavaVM = vm;
  vm->GetEnv((void **)&env, JNI_VERSION_1_4);

  android::register_android_database_SQLiteConnection(env);
  android::register_android_database_SQLiteDebug(env);
  android::register_android_database_SQLiteGlobal(env);

  return JNI_VERSION_1_4;
}