vm/hprof/HprofClass.c

/*
 * Copyright (C) 2008 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.
 */
/*
 * Class object pool
 */

#include "Hprof.h"

static HashTable *gClassHashTable;

int
hprofStartup_Class()
{
    gClassHashTable = dvmHashTableCreate(128, NULL);
    if (gClassHashTable == NULL) {
        return UNIQUE_ERROR();
    }
    return 0;
}

int
hprofShutdown_Class()
{
    dvmHashTableFree(gClassHashTable);

    return 0;
}

static u4
computeClassHash(const ClassObject *clazz)
{
    u4 hash;
    const char *cp;
    char c;

    cp = clazz->descriptor;
    hash = (u4)clazz->classLoader;
    while ((c = *cp++) != '\0') {
        hash = hash * 31 + c;
    }

    return hash;
}

static int
classCmp(const void *v1, const void *v2)
{
    const ClassObject *c1 = (const ClassObject *)v1;
    const ClassObject *c2 = (const ClassObject *)v2;
    intptr_t diff;

    diff = (uintptr_t)c1->classLoader - (uintptr_t)c2->classLoader;
    if (diff == 0) {
        return strcmp(c1->descriptor, c2->descriptor);
    }
    return diff;
}

static int
getPrettyClassNameId(const char *descriptor)
{
    hprof_string_id classNameId;
    char *dotName = dvmDescriptorToDot(descriptor);
    
    /* Hprof suggests that array class names be converted from, e.g.,
     * "[[[I" to "int[][][]" and "[Lorg.blort.Spaz;" to
     * "org.blort.Spaz[]".
     */
    if (dotName[0] == '[') {
        const char *c;
        char *newName;
        char *nc;
        size_t dim;
        size_t newLen;

        c = dotName;
        dim = 0;
        while (*c == '[') {
            dim++;
            c++;
        }
        if (*c == 'L') {
            c++;
        } else {
            /* It's a primitive type;  we should use a pretty name.
             * Add semicolons to make all strings have the format
             * of object class names.
             */
            switch (*c) {
            case 'Z': c = "boolean;";    break;
            case 'C': c = "char;";       break;
            case 'F': c = "float;";      break;
            case 'D': c = "double;";     break;
            case 'B': c = "byte;";       break;
            case 'S': c = "short;";      break;
            case 'I': c = "int;";        break;
            case 'J': c = "long;";       break;
            default: assert(false); c = "UNKNOWN;"; break;
            }
        }

        /* We have a string of the form "name;" and
         * we want to replace the semicolon with as many
         * "[]" pairs as is in dim.
         */
        newLen = strlen(c)-1 + dim*2;
        newName = malloc(newLen + 1);
        if (newName == NULL) {
            return -1;
        }
        strcpy(newName, c);
        newName[newLen] = '\0';

        /* Point nc to the semicolon.
         */
        nc = newName + newLen - dim*2;
        assert(*nc == ';');

        while (dim--) {
            *nc++ = '[';
            *nc++ = ']';
        }
        assert(*nc == '\0');

        classNameId = hprofLookupStringId(newName);
        free(newName);
    } else {
        classNameId = hprofLookupStringId(dotName);
    }

    free(dotName);
    return classNameId;
}


hprof_class_object_id
hprofLookupClassId(const ClassObject *clazz)
{
    void *val;

    if (clazz == NULL) {
        /* Someone's probably looking up the superclass
         * of java.lang.Object or of a primitive class.
         */
        return (hprof_class_object_id)0;
    }

    dvmHashTableLock(gClassHashTable);

    /* We're using the hash table as a list.
     * TODO: replace the hash table with a more suitable structure
     */
    val = dvmHashTableLookup(gClassHashTable, computeClassHash(clazz),
            (void *)clazz, classCmp, true);
    assert(val != NULL);

    dvmHashTableUnlock(gClassHashTable);

    /* Make sure that the class's name is in the string table.
     * This is a bunch of extra work that we only have to do
     * because of the order of tables in the output file
     * (strings need to be dumped before classes).
     */
    getPrettyClassNameId(clazz->descriptor);

    return (hprof_class_object_id)clazz;
}

int
hprofDumpClasses(hprof_context_t *ctx)
{
    HashIter iter;
    hprof_record_t *rec = &ctx->curRec;
    int err;

    dvmHashTableLock(gClassHashTable);

    for (err = 0, dvmHashIterBegin(gClassHashTable, &iter);
         err == 0 && !dvmHashIterDone(&iter);
         dvmHashIterNext(&iter))
    {
        err = hprofStartNewRecord(ctx, HPROF_TAG_LOAD_CLASS, HPROF_TIME);
        if (err == 0) {
            const ClassObject *clazz;

            clazz = (const ClassObject *)dvmHashIterData(&iter);
            assert(clazz != NULL);

            /* LOAD CLASS format:
             *
             * u4:     class serial number (always > 0)
             * ID:     class object ID
             * u4:     stack trace serial number
             * ID:     class name string ID
             * 
             * We use the address of the class object structure as its ID.
             */
            hprofAddU4ToRecord(rec, clazz->serialNumber);
            hprofAddIdToRecord(rec, (hprof_class_object_id)clazz);
            hprofAddU4ToRecord(rec, HPROF_NULL_STACK_TRACE);
            hprofAddIdToRecord(rec, getPrettyClassNameId(clazz->descriptor));
        }
    }

    dvmHashTableUnlock(gClassHashTable);

    return err;
}