/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.vm.ci.hotspot;

import jdk.vm.ci.common.JVMCIError;

/**

 * Access to VM configuration data.

 */

public class HotSpotVMConfigAccess {

    /**

     * Gets the available configuration data.

     */

    public HotSpotVMConfigStore getStore() {

        return store;

    }

    /**

     * Gets the address of a C++ symbol.

     *

     * @param name name of C++ symbol

     * @param notPresent if non-null and the symbol is not present then this value is returned

     * @return the address of the symbol

     * @throws JVMCIError if the symbol is not present and {@code notPresent == null}

     */

    public long getAddress(String name, Long notPresent) {

        Long entry = store.vmAddresses.get(name);

        if (entry == null) {

            if (notPresent != null) {

                return notPresent;

            }

        }

        return entry;

    }

    /**

     * Gets the address of a C++ symbol.

     *

     * @param name name of C++ symbol

     * @return the address of the symbol

     * @throws JVMCIError if the symbol is not present

     */

    public long getAddress(String name) {

        return getAddress(name, null);

    }

    /**

     * Gets the value of a C++ constant.

     *

     * @param name name of the constant (e.g., {@code "frame::arg_reg_save_area_bytes"})

     * @param type the boxed type to which the constant value will be converted

     * @param notPresent if non-null and the constant is not present then this value is returned

     * @return the constant value converted to {@code type}

     * @throws JVMCIError if the constant is not present and {@code notPresent == null}

     */

    public <T> T getConstant(String name, Class<T> type, T notPresent) {

        Long c = store.vmConstants.get(name);

        if (c == null) {

            if (notPresent != null) {

                return notPresent;

            }

        }

        return type.cast(convertValue(name, type, c, null));

    }

    /**

     * Gets the value of a C++ constant.

     *

     * @param name name of the constant (e.g., {@code "frame::arg_reg_save_area_bytes"})

     * @param type the boxed type to which the constant value will be converted

     * @return the constant value converted to {@code type}

     * @throws JVMCIError if the constant is not present

     */

    public <T> T getConstant(String name, Class<T> type) {

        return getConstant(name, type, null);

    }

    /**

     * Gets the offset of a non-static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the offset value will be converted (must be

     *            {@link Integer} or {@link Long})

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @param notPresent if non-null and the field is not present then this value is returned

     * @return the offset in bytes of the requested field

     * @throws JVMCIError if the field is static or not present and {@code notPresent} is null

     */

    public <T> T getFieldOffset(String name, Class<T> type, String cppType, T notPresent) {

    }

    /**

     * Gets the offset of a non-static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the offset value will be converted (must be

     *            {@link Integer} or {@link Long})

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @return the offset in bytes of the requested field

     * @throws JVMCIError if the field is static or not present

     */

    public <T> T getFieldOffset(String name, Class<T> type, String cppType) {

    }

    /**

     * Gets the offset of a non-static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the offset value will be converted (must be

     *            {@link Integer} or {@link Long})

     * @return the offset in bytes of the requested field

     * @throws JVMCIError if the field is static or not present

     */

    public <T> T getFieldOffset(String name, Class<T> type) {

    }

    /**

     * Gets the address of a static C++ field.

     *

     * @param name fully qualified name of the field

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @param notPresent if non-null and the field is not present then this value is returned

     * @return the address of the requested field

     * @throws JVMCIError if the field is not static or not present and {@code notPresent} is null

     */

    public long getFieldAddress(String name, String cppType, Long notPresent) {

    }

    /**

     * Gets the address of a static C++ field.

     *

     * @param name fully qualified name of the field

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @return the address of the requested field

     * @throws JVMCIError if the field is not static or not present

     */

    public long getFieldAddress(String name, String cppType) {

    }

    /**

     * Gets the value of a static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the constant value will be converted

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @param notPresent if non-null and the field is not present then this value is returned

     * @return the value of the requested field

     * @throws JVMCIError if the field is not static or not present and {@code notPresent} is null

     */

    public <T> T getFieldValue(String name, Class<T> type, String cppType, T notPresent) {

    }

    /**

     * Gets the value of a static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the constant value will be converted

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @return the value of the requested field

     * @throws JVMCIError if the field is not static or not present

     */

    public <T> T getFieldValue(String name, Class<T> type, String cppType) {

    }

    /**

     * Gets the value of a static C++ field.

     *

     * @param name fully qualified name of the field

     * @param type the boxed type to which the constant value will be converted

     * @return the value of the requested field

     * @throws JVMCIError if the field is not static or not present

     */

    public <T> T getFieldValue(String name, Class<T> type) {

    }

    /**

     * Gets a C++ field.

     *

     * @param name fully qualified name of the field

     * @param cppType if non-null, the expected C++ type of the field (e.g., {@code "HeapWord*"})

     * @param required specifies if the field must be present

     * @return the field

     * @throws JVMCIError if the field is not present and {@code required == true}

     */

    private VMField getField(String name, String cppType, boolean required) {

        VMField entry = store.vmFields.get(name);

        if (entry == null) {

            if (!required) {

                return null;

            }

        }

        // Make sure the native type is still the type we expect.

        if (cppType != null && !cppType.equals(entry.type)) {

            throw new JVMCIError("expected type " + cppType + " but VM field " + name + " is of type " + entry.type);

        }

        return entry;

    }

    /**

     * Gets a VM flag value.

     *

     * @param name name of the flag (e.g., {@code "CompileTheWorldStartAt"})

     * @param type the boxed type to which the flag's value will be converted

     * @return the flag's value converted to {@code type} or {@code notPresent} if the flag is not

     *         present

     * @throws JVMCIError if the flag is not present

     */

    public <T> T getFlag(String name, Class<T> type) {

        return getFlag(name, type, null);

    }

    /**

     * Gets a VM flag value.

     *

     * @param name name of the flag (e.g., {@code "CompileTheWorldStartAt"})

     * @param type the boxed type to which the flag's value will be converted

     * @param notPresent if non-null and the flag is not present then this value is returned

     * @return the flag's value converted to {@code type} or {@code notPresent} if the flag is not

     *         present

     * @throws JVMCIError if the flag is not present and {@code notPresent == null}

     */

    public <T> T getFlag(String name, Class<T> type, T notPresent) {

        VMFlag entry = store.vmFlags.get(name);

        Object value;

        String cppType;

        if (entry == null) {

            // Fall back to VM call

            value = store.compilerToVm.getFlagValue(name);

            if (value == store.compilerToVm) {

                if (notPresent != null) {

                    return notPresent;

                }

            } else {

                cppType = null;

            }

        } else {

            value = entry.value;

            cppType = entry.type;

        }

        return type.cast(convertValue(name, type, value, cppType));

    }

    private static <T> Object convertValue(String name, Class<T> toType, Object value, String cppType) throws JVMCIError {

        if (toType == Boolean.class) {

            if (value instanceof String) {

                return Boolean.valueOf((String) value);

            } else if (value instanceof Boolean) {

                return value;

            } else if (value instanceof Long) {

                return ((long) value) != 0;

            }

        } else if (toType == Byte.class) {

            if (value instanceof Long) {

                return (byte) (long) value;

            }

        } else if (toType == Integer.class) {

            if (value instanceof Integer) {

                return value;

            } else if (value instanceof Long) {

                return (int) (long) value;

            }

        } else if (toType == String.class) {

            if (value == null || value instanceof String) {

                return value;

            }

        } else if (toType == Long.class) {

            return value;

        }

        throw new JVMCIError("cannot convert " + name + " of type " + value.getClass().getSimpleName() + (cppType == null ? "" : " [" + cppType + "]") + " to " + toType.getSimpleName());

    }

    private final HotSpotVMConfigStore store;

    public HotSpotVMConfigAccess(HotSpotVMConfigStore store) {

        this.store = store;

    }

}