/*

 * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.

 * 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.meta;

/**

 * Miscellaneous collection of utility methods used by {@code jdk.vm.ci.meta} and its clients.

 */

public class MetaUtil {

    private static class ClassInfo {

        public long totalSize;

        public long instanceCount;

        @Override

        public String toString() {

            return "totalSize=" + totalSize + ", instanceCount=" + instanceCount;

        }

    }

    /**

     * Returns the number of bytes occupied by this constant value or constant object and

     * recursively all values reachable from this value.

     *

     * @param constant the constant whose bytes should be measured

     * @param printTopN print total size and instance count of the top n classes is desired

     * @return the number of bytes occupied by this constant

     */

    public static long getMemorySizeRecursive(MetaAccessProvider access, ConstantReflectionProvider constantReflection, JavaConstant constant, PrintStream out, int printTopN) {

        Set<JavaConstant> marked = new HashSet<>();

        Deque<JavaConstant> stack = new ArrayDeque<>();

        if (constant.getJavaKind() == JavaKind.Object && constant.isNonNull()) {

            marked.add(constant);

        }

        final HashMap<ResolvedJavaType, ClassInfo> histogram = new HashMap<>();

        stack.push(constant);

        long sum = 0;

        while (!stack.isEmpty()) {

            JavaConstant c = stack.pop();

            long memorySize = access.getMemorySize(constant);

            sum += memorySize;

            if (c.getJavaKind() == JavaKind.Object && c.isNonNull()) {

                ResolvedJavaType clazz = access.lookupJavaType(c);

                if (!histogram.containsKey(clazz)) {

                    histogram.put(clazz, new ClassInfo());

                }

                ClassInfo info = histogram.get(clazz);

                info.instanceCount++;

                info.totalSize += memorySize;

                ResolvedJavaType type = access.lookupJavaType(c);

                if (type.isArray()) {

                    if (!type.getComponentType().isPrimitive()) {

                        int length = constantReflection.readArrayLength(c);

                        for (int i = 0; i < length; i++) {

                            JavaConstant value = constantReflection.readArrayElement(c, i);

                            pushConstant(marked, stack, value);

                        }

                    }

                } else {

                    ResolvedJavaField[] instanceFields = type.getInstanceFields(true);

                    for (ResolvedJavaField f : instanceFields) {

                        if (f.getJavaKind() == JavaKind.Object) {

                            JavaConstant value = constantReflection.readFieldValue(f, c);

                            pushConstant(marked, stack, value);

                        }

                    }

                }

            }

        }

        ArrayList<ResolvedJavaType> clazzes = new ArrayList<>();

        clazzes.addAll(histogram.keySet());

        Collections.sort(clazzes, new Comparator<ResolvedJavaType>() {

            @Override

            public int compare(ResolvedJavaType o1, ResolvedJavaType o2) {

                long l1 = histogram.get(o1).totalSize;

                long l2 = histogram.get(o2).totalSize;

                if (l1 > l2) {

                    return -1;

                } else if (l1 == l2) {

                    return 0;

                } else {

                    return 1;

                }

            }

        });

        int z = 0;

        for (ResolvedJavaType c : clazzes) {

            if (z > printTopN) {

                break;

            }

            out.println("Class " + c + ", " + histogram.get(c));

            ++z;

        }

        return sum;

    }

    private static void pushConstant(Set<JavaConstant> marked, Deque<JavaConstant> stack, JavaConstant value) {

        if (value.isNonNull()) {

            if (!marked.contains(value)) {

                marked.add(value);

                stack.push(value);

            }

        }

    }

    /**

     * Calls {@link JavaType#resolve(ResolvedJavaType)} on an array of types.

     */

    public static ResolvedJavaType[] resolveJavaTypes(JavaType[] types, ResolvedJavaType accessingClass) {

        ResolvedJavaType[] result = new ResolvedJavaType[types.length];

        for (int i = 0; i < result.length; i++) {

            result[i] = types[i].resolve(accessingClass);

        }

        return result;

    }

    /**

     * Extends the functionality of {@link Class#getSimpleName()} to include a non-empty string for

     * anonymous and local classes.

     *

     * @param clazz the class for which the simple name is being requested

     * @param withEnclosingClass specifies if the returned name should be qualified with the name(s)

     *            of the enclosing class/classes of {@code clazz} (if any). This option is ignored

     *            if {@code clazz} denotes an anonymous or local class.

     * @return the simple name

     */

    public static String getSimpleName(Class<?> clazz, boolean withEnclosingClass) {

        final String simpleName = clazz.getSimpleName();

        if (simpleName.length() != 0) {

            if (withEnclosingClass) {

                String prefix = "";

                Class<?> enclosingClass = clazz;

                while ((enclosingClass = enclosingClass.getEnclosingClass()) != null) {

                    prefix = enclosingClass.getSimpleName() + "." + prefix;

                }

                return prefix + simpleName;

            }

            return simpleName;

        }

        // Must be an anonymous or local class

        final String name = clazz.getName();

        int index = name.indexOf('$');

        if (index == -1) {

            return name;

        }

        index = name.lastIndexOf('.', index);

        if (index == -1) {

            return name;

        }

        return name.substring(index + 1);

    }

    static String internalNameToJava(String name, boolean qualified, boolean classForNameCompatible) {

        switch (name.charAt(0)) {

            case 'L': {

                String result = name.substring(1, name.length() - 1).replace('/', '.');

                if (!qualified) {

                    final int lastDot = result.lastIndexOf('.');

                    if (lastDot != -1) {

                        result = result.substring(lastDot + 1);

                    }

                }

                return result;

            }

            case '[':

                return classForNameCompatible ? name.replace('/', '.') : internalNameToJava(name.substring(1), qualified, classForNameCompatible) + "[]";

            default:

                if (name.length() != 1) {

                    throw new IllegalArgumentException("Illegal internal name: " + name);

                }

                return JavaKind.fromPrimitiveOrVoidTypeChar(name.charAt(0)).getJavaName();

        }

    }

    /**

     * Turns an class name in internal format into a resolved Java type.

     */

    public static ResolvedJavaType classForName(String internal, MetaAccessProvider metaAccess, ClassLoader cl) {

        JavaKind k = JavaKind.fromTypeString(internal);

        try {

            String n = internalNameToJava(internal, true, true);

            return metaAccess.lookupJavaType(k.isPrimitive() ? k.toJavaClass() : Class.forName(n, true, cl));

        } catch (ClassNotFoundException cnfe) {

            throw new IllegalArgumentException("could not instantiate class described by " + internal, cnfe);

        }

    }

    /**

     * Convenient shortcut for calling

     * {@link #appendLocation(StringBuilder, ResolvedJavaMethod, int)} without having to supply a

     * {@link StringBuilder} instance and convert the result to a string.

     */

    public static String toLocation(ResolvedJavaMethod method, int bci) {

        return appendLocation(new StringBuilder(), method, bci).toString();

    }

    /**

     * Appends a string representation of a location specified by a given method and bci to a given

     * {@link StringBuilder}. If a stack trace element with a non-null file name and non-negative

     * line number is {@linkplain ResolvedJavaMethod#asStackTraceElement(int) available} for the

     * given method, then the string returned is the {@link StackTraceElement#toString()} value of

     * the stack trace element, suffixed by the bci location. For example:

     *

     * <pre>

     *     java.lang.String.valueOf(String.java:2930) [bci: 12]

     * </pre>

     *

     * Otherwise, the string returned is the value of applying {@link JavaMethod#format(String)}

     * with the format string {@code "%H.%n(%p)"}, suffixed by the bci location. For example:

     *

     * <pre>

     *     java.lang.String.valueOf(int) [bci: 12]

     * </pre>

     *

     * @param sb

     * @param method

     * @param bci

     */

    public static StringBuilder appendLocation(StringBuilder sb, ResolvedJavaMethod method, int bci) {

        if (method != null) {

            StackTraceElement ste = method.asStackTraceElement(bci);

            if (ste.getFileName() != null && ste.getLineNumber() > 0) {

                sb.append(ste);

            } else {

                sb.append(method.format("%H.%n(%p)"));

            }

        } else {

            sb.append("Null method");

        }

        return sb.append(" [bci: ").append(bci).append(']');

    }

    static void appendProfile(StringBuilder buf, AbstractJavaProfile<?, ?> profile, int bci, String type, String sep) {

        if (profile != null) {

            AbstractProfiledItem<?>[] pitems = profile.getItems();

            if (pitems != null) {

                buf.append(String.format("%s@%d:", type, bci));

                for (int j = 0; j < pitems.length; j++) {

                    AbstractProfiledItem<?> pitem = pitems[j];

                    buf.append(String.format(" %.6f (%s)%s", pitem.getProbability(), pitem.getItem(), sep));

                }

                if (profile.getNotRecordedProbability() != 0) {

                    buf.append(String.format(" %.6f <other %s>%s", profile.getNotRecordedProbability(), type, sep));

                } else {

                    buf.append(String.format(" <no other %s>%s", type, sep));

                }

            }

        }

    }

    /**

     * Converts a Java source-language class name into the internal form.

     *

     * @param className the class name

     * @return the internal name form of the class name

     */

    public static String toInternalName(String className) {

        if (className.startsWith("[")) {

            /* Already in the correct array style. */

            return className.replace('.', '/');

        }

        StringBuilder result = new StringBuilder();

        String base = className;

        while (base.endsWith("[]")) {

            result.append("[");

            base = base.substring(0, base.length() - 2);

        }

        switch (base) {

            case "boolean":

                result.append("Z");

                break;

            case "byte":

                result.append("B");

                break;

            case "short":

                result.append("S");

                break;

            case "char":

                result.append("C");

                break;

            case "int":

                result.append("I");

                break;

            case "float":

                result.append("F");

                break;

            case "long":

                result.append("J");

                break;

            case "double":

                result.append("D");

                break;

            case "void":

                result.append("V");

                break;

            default:

                result.append("L").append(base.replace('.', '/')).append(";");

                break;

        }

        return result.toString();

    }

    /**

     * Prepends the String {@code indentation} to every line in String {@code lines}, including a

     * possibly non-empty line following the final newline.

     */

    public static String indent(String lines, String indentation) {

        if (lines.length() == 0) {

            return lines;

        }

        final String newLine = "\n";

        if (lines.endsWith(newLine)) {

            return indentation + (lines.substring(0, lines.length() - 1)).replace(newLine, newLine + indentation) + newLine;

        }

        return indentation + lines.replace(newLine, newLine + indentation);

    }

    /**

     * Gets a string representation of an object based soley on its class and its

     * {@linkplain System#identityHashCode(Object) identity hash code}. This avoids and calls to

     * virtual methods on the object such as {@link Object#hashCode()}.

     */

    public static String identityHashCodeString(Object obj) {

        if (obj == null) {

            return "null";

        }

        return obj.getClass().getName() + "@" + System.identityHashCode(obj);

    }

    /**

     * Used to lookup constants from {@link Modifier} that are not public (VARARGS, SYNTHETIC etc.).

     */

    static int getNonPublicModifierStaticField(String name) {

        try {

            Field field = Modifier.class.getDeclaredField(name);

            field.setAccessible(true);

            return field.getInt(null);

        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {

            throw new InternalError(e);

        }

    }

}