Source Format Enforcement (#532)

[thirdparty/squid.git] / src / cache_diff.cc

/*
 * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/*
 * Computes the difference between the contents of two caches
 * using swap logs
 * Reports the percentage of common files and other stats
 */

#include "squid.h"
#include <cerrno>

typedef struct {
    const char *name;
    hash_table *hash;
    int count;          /* #currently cached entries */
    int scanned_count;      /* #scanned entries */
    int bad_add_count;      /* #duplicate adds */
    int bad_del_count;      /* #dels with no prior add */
} CacheIndex;

typedef struct _CacheEntry {
    const cache_key *key;

    struct _CacheEntry *next;
    /* StoreSwapLogData s; */
    unsigned char key_arr[SQUID_MD5_DIGEST_LENGTH];
} CacheEntry;

static int cacheIndexScan(CacheIndex * idx, const char *fname, FILE * file);

static CacheEntry *
cacheEntryCreate(const StoreSwapLogData * s)
{
    CacheEntry *e = xcalloc(1, sizeof(CacheEntry));
    assert(s);
    /* e->s = *s; */
    memcpy(e->key_arr, s->key, SQUID_MD5_DIGEST_LENGTH);
    e->key = &e->key_arr[0];
    return e;
}

static void
cacheEntryDestroy(CacheEntry * e)
{
    assert(e);
    xfree(e);
}

static CacheIndex *
cacheIndexCreate(const char *name)
{
    CacheIndex *idx;

    if (!name || !strlen(name))
        return NULL;

    idx = xcalloc(1, sizeof(CacheIndex));

    idx->name = name;

    idx->hash = hash_create(storeKeyHashCmp, 2e6, storeKeyHashHash);

    return idx;
}

static void
cacheIndexDestroy(CacheIndex * idx)
{
    hash_link *hashr = NULL;

    if (idx) {
        /* destroy hash list contents */
        hash_first(idx->hash);

        while (hashr = hash_next(idx->hash)) {
            hash_remove_link(idx->hash, hashr);
            cacheEntryDestroy((CacheEntry *) hashr);
        }

        /* destroy the hash table itself */
        hashFreeMemory(idx->hash);

        xfree(idx);
    }
}

static int
cacheIndexAddLog(CacheIndex * idx, const char *fname)
{
    FILE *file;
    int scanned_count = 0;
    assert(idx);
    assert(fname && strlen(fname));

    file = fopen(fname, "r");

    if (!file) {
        fprintf(stderr, "cannot open %s: %s\n", fname, strerror(errno));
        return 0;
    }

#if _SQUID_WINDOWS_
    setmode(fileno(file), O_BINARY);
#endif

    scanned_count = cacheIndexScan(idx, fname, file);

    fclose(file);

    return scanned_count;
}

static void
cacheIndexInitReport(CacheIndex * idx)
{
    assert(idx);
    fprintf(stderr, "%s: bad swap_add:  %d\n",
            idx->name, idx->bad_add_count);
    fprintf(stderr, "%s: bad swap_del:  %d\n",
            idx->name, idx->bad_del_count);
    fprintf(stderr, "%s: scanned lines: %d\n",
            idx->name, idx->scanned_count);
}

static int
cacheIndexScan(CacheIndex * idx, const char *fname, FILE * file)
{
    int count = 0;
    StoreSwapLogData s;
    fprintf(stderr, "%s scanning\n", fname);

    while (fread(&s, sizeof(s), 1, file) == 1) {
        ++count;
        ++ idx->scanned_count;
        /* if (!s.sane())
         * continue; */

        if (s.op == SWAP_LOG_ADD) {
            CacheEntry *olde = (CacheEntry *) hash_lookup(idx->hash, s.key);

            if (olde) {
                ++ idx->bad_add_count;
            } else {
                CacheEntry *e = cacheEntryCreate(&s);
                hash_join(idx->hash, &e->hash);
                ++ idx->count;
            }
        } else if (s.op == SWAP_LOG_DEL) {
            CacheEntry *olde = (CacheEntry *) hash_lookup(idx->hash, s.key);

            if (!olde)
                ++ idx->bad_del_count;
            else {
                assert(idx->count);
                hash_remove_link(idx->hash, (hash_link *) olde);
                cacheEntryDestroy(olde);
                -- idx->count;
            }
        } else {
            fprintf(stderr, "%s:%d: unknown swap log action\n", fname, count);
            exit(-3);
        }
    }

    fprintf(stderr, "%s:%d: scanned (size: %d bytes)\n",
            fname, count, (int) (count * sizeof(CacheEntry)));
    return count;
}

static void
cacheIndexCmpReport(CacheIndex * idx, int shared_count)
{
    assert(idx && shared_count <= idx->count);

    printf("%s:\t %7d = %7d + %7d (%7.2f%% + %7.2f%%)\n",
           idx->name,
           idx->count,
           idx->count - shared_count,
           shared_count,
           xpercent(idx->count - shared_count, idx->count),
           xpercent(shared_count, idx->count));
}

static void
cacheIndexCmp(CacheIndex * idx1, CacheIndex * idx2)
{
    int shared_count = 0;
    int hashed_count = 0;
    hash_link *hashr = NULL;
    CacheIndex *small_idx = idx1;
    CacheIndex *large_idx = idx2;
    assert(idx1 && idx2);

    /* check our guess */

    if (idx1->count > idx2->count) {
        small_idx = idx2;
        large_idx = idx1;
    }

    /* find shared_count */
    hash_first(small_idx->hash);

    for (hashr = hash_next(small_idx->hash)) {
        ++hashed_count;

        if (hash_lookup(large_idx->hash, hashr->key))
            ++shared_count;
    }

    assert(hashed_count == small_idx->count);

    cacheIndexCmpReport(idx1, shared_count);
    cacheIndexCmpReport(idx2, shared_count);
}

static int
usage(const char *prg_name)
{
    fprintf(stderr, "usage: %s <label1>: <swap_state>... <label2>: <swap_state>...\n",
            prg_name);
    return EXIT_FAILURE;
}

int
main(int argc, char *argv[])
{
    CacheIndex *CacheIdx[2];
    CacheIndex *idx = NULL;
    int idxCount = 0;
    int i;

    if (argc < 5)
        return usage(argv[0]);

    for (i = 1; i < argc; ++i) {
        const int len = strlen(argv[i]);

        if (!len)
            return usage(argv[0]);

        if (argv[i][len - 1] == ':') {
            ++idxCount;

            if (len < 2 || idxCount > 2)
                return usage(argv[0]);

            idx = cacheIndexCreate(argv[i]);

            CacheIdx[idxCount - 1] = idx;
        } else {
            if (!idx)
                return usage(argv[0]);

            cacheIndexAddLog(idx, argv[i]);
        }
    }

    if (idxCount != 2)
        return usage(argv[0]);

    cacheIndexInitReport(CacheIdx[0]);

    cacheIndexInitReport(CacheIdx[1]);

    cacheIndexCmp(CacheIdx[0], CacheIdx[1]);

    cacheIndexDestroy(CacheIdx[0]);

    cacheIndexDestroy(CacheIdx[1]);

    return EXIT_FAILURE;
}