release GVL for filesystem operations

[clogger.git] / ext / clogger_ext / clogger.c

#include <ruby.h>
#ifdef HAVE_RUBY_IO_H
#  include <ruby/io.h>
#else
#  include <rubyio.h>
#endif
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <errno.h>
#ifdef HAVE_FCNTL_H
#  include <fcntl.h>
#endif
#ifndef _POSIX_C_SOURCE
#  define _POSIX_C_SOURCE 200112L
#endif
#include <time.h>
#include "ruby_1_9_compat.h"
#include "broken_system_compat.h"
#include "blocking_helpers.h"

/*
 * Availability of a monotonic clock needs to be detected at runtime
 * since we could've been built on a different system than we're run
 * under.
 */
static clockid_t hopefully_CLOCK_MONOTONIC;

static void check_clock(void)
{
        struct timespec now;

        hopefully_CLOCK_MONOTONIC = CLOCK_MONOTONIC;

        /* we can't check this reliably at compile time */
        if (clock_gettime(CLOCK_MONOTONIC, &now) == 0)
                return;

        if (clock_gettime(CLOCK_REALTIME, &now) == 0) {
                hopefully_CLOCK_MONOTONIC = CLOCK_REALTIME;
                rb_warn("CLOCK_MONOTONIC not available, "
                        "falling back to CLOCK_REALTIME");
        }
        rb_warn("clock_gettime() totally broken, " \
                "falling back to pure Ruby Clogger");
        rb_raise(rb_eLoadError, "clock_gettime() broken");
}

static void clock_diff(struct timespec *a, const struct timespec *b)
{
        a->tv_sec -= b->tv_sec;
        a->tv_nsec -= b->tv_nsec;
        if (a->tv_nsec < 0) {
                --a->tv_sec;
                a->tv_nsec += 1000000000;
        }
}

/* give GCC hints for better branch prediction
 * (we layout branches so that ASCII characters are handled faster) */
#if defined(__GNUC__) && (__GNUC__ >= 3)
#  define likely(x)             __builtin_expect (!!(x), 1)
#  define unlikely(x)           __builtin_expect (!!(x), 0)
#else
#  define unlikely(x)           (x)
#  define likely(x)             (x)
#endif

enum clogger_opcode {
        CL_OP_LITERAL = 0,
        CL_OP_REQUEST,
        CL_OP_RESPONSE,
        CL_OP_SPECIAL,
        CL_OP_EVAL,
        CL_OP_TIME_LOCAL,
        CL_OP_TIME_UTC,
        CL_OP_REQUEST_TIME,
        CL_OP_TIME,
        CL_OP_COOKIE
};

enum clogger_special {
        CL_SP_body_bytes_sent = 0,
        CL_SP_status,
        CL_SP_request,
        CL_SP_request_length,
        CL_SP_response_length,
        CL_SP_ip,
        CL_SP_pid,
        CL_SP_request_uri
};

struct clogger {
        VALUE app;

        VALUE fmt_ops;
        VALUE logger;
        VALUE log_buf;

        VALUE env;
        VALUE cookies;
        VALUE status;
        VALUE headers;
        VALUE body;

        off_t body_bytes_sent;
        struct timespec ts_start;

        int fd;
        int wrap_body;
        int need_resp;
        int reentrant; /* tri-state, -1:auto, 1/0 true/false */
};

static ID ltlt_id;
static ID call_id;
static ID each_id;
static ID close_id;
static ID to_i_id;
static ID to_s_id;
static ID size_id;
static ID sq_brace_id;
static ID new_id;
static ID to_path_id;
static ID to_io_id;
static ID respond_to_id;
static VALUE cClogger;
static VALUE mFormat;
static VALUE cHeaderHash;

/* common hash lookup keys */
static VALUE g_HTTP_X_FORWARDED_FOR;
static VALUE g_REMOTE_ADDR;
static VALUE g_REQUEST_METHOD;
static VALUE g_PATH_INFO;
static VALUE g_REQUEST_URI;
static VALUE g_QUERY_STRING;
static VALUE g_HTTP_VERSION;
static VALUE g_rack_errors;
static VALUE g_rack_input;
static VALUE g_rack_multithread;
static VALUE g_dash;
static VALUE g_space;
static VALUE g_question_mark;
static VALUE g_rack_request_cookie_hash;

#define LOG_BUF_INIT_SIZE 128

static void init_buffers(struct clogger *c)
{
        c->log_buf = rb_str_buf_new(LOG_BUF_INIT_SIZE);
}

static inline int need_escape(unsigned c)
{
        assert(c <= 0xff);
        return !!(c == '\'' || c == '"' || c <= 0x1f);
}

/* we are encoding-agnostic, clients can send us all sorts of junk */
static VALUE byte_xs_str(VALUE from)
{
        static const char esc[] = "0123456789ABCDEF";
        unsigned char *new_ptr;
        unsigned char *ptr = (unsigned char *)RSTRING_PTR(from);
        long len = RSTRING_LEN(from);
        long new_len = len;
        VALUE rv;

        for (; --len >= 0; ptr++) {
                unsigned c = *ptr;

                if (unlikely(need_escape(c)))
                        new_len += 3; /* { '\', 'x', 'X', 'X' } */
        }

        len = RSTRING_LEN(from);
        if (new_len == len)
                return from;

        rv = rb_str_new(NULL, new_len);
        new_ptr = (unsigned char *)RSTRING_PTR(rv);
        ptr = (unsigned char *)RSTRING_PTR(from);
        for (; --len >= 0; ptr++) {
                unsigned c = *ptr;

                if (unlikely(need_escape(c))) {
                        *new_ptr++ = '\\';
                        *new_ptr++ = 'x';
                        *new_ptr++ = esc[c >> 4];
                        *new_ptr++ = esc[c & 0xf];
                } else {
                        *new_ptr++ = c;
                }
        }
        assert(RSTRING_PTR(rv)[RSTRING_LEN(rv)] == '\0');

        return rv;
}

static VALUE byte_xs(VALUE from)
{
        return byte_xs_str(rb_obj_as_string(from));
}

static void clogger_mark(void *ptr)
{
        struct clogger *c = ptr;

        rb_gc_mark(c->app);
        rb_gc_mark(c->fmt_ops);
        rb_gc_mark(c->logger);
        rb_gc_mark(c->log_buf);
        rb_gc_mark(c->env);
        rb_gc_mark(c->cookies);
        rb_gc_mark(c->status);
        rb_gc_mark(c->headers);
        rb_gc_mark(c->body);
}

static VALUE clogger_alloc(VALUE klass)
{
        struct clogger *c;

        return Data_Make_Struct(klass, struct clogger, clogger_mark, -1, c);
}

static struct clogger *clogger_get(VALUE self)
{
        struct clogger *c;

        Data_Get_Struct(self, struct clogger, c);
        assert(c);
        return c;
}

/* only for writing to regular files, not stupid crap like NFS  */
static void write_full(int fd, const void *buf, size_t count)
{
        ssize_t r;
        unsigned long ubuf = (unsigned long)buf;

        while (count > 0) {
                r = write(fd, (void *)ubuf, count);

                if ((size_t)r == count) { /* overwhelmingly likely */
                        return;
                } else if (r > 0) {
                        count -= r;
                        ubuf += r;
                } else {
                        if (errno == EINTR || errno == EAGAIN)
                                continue; /* poor souls on NFS and like: */
                        if (!errno)
                                errno = ENOSPC;
                        rb_sys_fail("write");
                }
        }
}

/*
 * allow us to use write_full() iff we detect a blocking file
 * descriptor that wouldn't play nicely with Ruby threading/fibers
 */
static int raw_fd(VALUE my_fd)
{
#if defined(HAVE_FCNTL) && defined(F_GETFL) && defined(O_NONBLOCK)
        int fd;
        int flags;

        if (NIL_P(my_fd))
                return -1;
        fd = NUM2INT(my_fd);

        flags = fcntl(fd, F_GETFL);
        if (flags < 0)
                rb_sys_fail("fcntl");

        if (flags & O_NONBLOCK) {
                struct stat sb;

                if (fstat(fd, &sb) < 0)
                        return -1;

                /* O_NONBLOCK is no-op for regular files: */
                if (! S_ISREG(sb.st_mode))
                        return -1;
        }
        return fd;
#else /* platforms w/o fcntl/F_GETFL/O_NONBLOCK */
        return -1;
#endif /* platforms w/o fcntl/F_GETFL/O_NONBLOCK */
}

/* :nodoc: */
static VALUE clogger_reentrant(VALUE self)
{
        return clogger_get(self)->reentrant == 0 ? Qfalse : Qtrue;
}

/* :nodoc: */
static VALUE clogger_wrap_body(VALUE self)
{
        return clogger_get(self)->wrap_body == 0 ? Qfalse : Qtrue;
}

static void append_status(struct clogger *c)
{
        char buf[sizeof("999")];
        int nr;
        VALUE status = c->status;

        if (TYPE(status) != T_FIXNUM) {
                status = rb_funcall(status, to_i_id, 0);
                /* no way it's a valid status code (at least not HTTP/1.1) */
                if (TYPE(status) != T_FIXNUM) {
                        rb_str_buf_append(c->log_buf, g_dash);
                        return;
                }
        }

        nr = FIX2INT(status);
        if (nr >= 100 && nr <= 999) {
                nr = snprintf(buf, sizeof(buf), "%03d", nr);
                assert(nr == 3);
                rb_str_buf_cat(c->log_buf, buf, nr);
        } else {
                /* raise?, swap for 500? */
                rb_str_buf_append(c->log_buf, g_dash);
        }
}

/* this is Rack 1.0.0-compatible, won't try to parse commas in XFF */
static void append_ip(struct clogger *c)
{
        VALUE env = c->env;
        VALUE tmp = rb_hash_aref(env, g_HTTP_X_FORWARDED_FOR);

        if (NIL_P(tmp)) {
                /* can't be faked on any real server, so no escape */
                tmp = rb_hash_aref(env, g_REMOTE_ADDR);
                if (NIL_P(tmp))
                        tmp = g_dash;
        } else {
                tmp = byte_xs(tmp);
        }
        rb_str_buf_append(c->log_buf, tmp);
}

static void append_body_bytes_sent(struct clogger *c)
{
        char buf[(sizeof(off_t) * 8) / 3 + 1];
        const char *fmt = sizeof(off_t) == sizeof(long) ? "%ld" : "%lld";
        int nr = snprintf(buf, sizeof(buf), fmt, c->body_bytes_sent);

        assert(nr > 0 && nr < (int)sizeof(buf));
        rb_str_buf_cat(c->log_buf, buf, nr);
}

static void append_ts(struct clogger *c, const VALUE *op, struct timespec *ts)
{
        char buf[sizeof(".000000") + ((sizeof(ts->tv_sec) * 8) / 3)];
        int nr;
        char *fmt = RSTRING_PTR(op[1]);
        int ndiv = NUM2INT(op[2]);
        int usec = ts->tv_nsec / 1000;

        nr = snprintf(buf, sizeof(buf), fmt,
                      (int)ts->tv_sec, (int)(usec / ndiv));
        assert(nr > 0 && nr < (int)sizeof(buf));
        rb_str_buf_cat(c->log_buf, buf, nr);
}

static void append_request_time_fmt(struct clogger *c, const VALUE *op)
{
        struct timespec now;

        clock_gettime(hopefully_CLOCK_MONOTONIC, &now);
        clock_diff(&now, &c->ts_start);
        append_ts(c, op, &now);
}

static void append_time_fmt(struct clogger *c, const VALUE *op)
{
        struct timespec now;
        int r = clock_gettime(CLOCK_REALTIME, &now);

        if (unlikely(r != 0))
                rb_sys_fail("clock_gettime(CLOCK_REALTIME)");
        append_ts(c, op, &now);
}

static void append_request_uri(struct clogger *c)
{
        VALUE tmp;

        tmp = rb_hash_aref(c->env, g_REQUEST_URI);
        if (NIL_P(tmp)) {
                tmp = rb_hash_aref(c->env, g_PATH_INFO);
                if (!NIL_P(tmp))
                        rb_str_buf_append(c->log_buf, byte_xs(tmp));
                tmp = rb_hash_aref(c->env, g_QUERY_STRING);
                if (!NIL_P(tmp) && RSTRING_LEN(tmp) != 0) {
                        rb_str_buf_append(c->log_buf, g_question_mark);
                        rb_str_buf_append(c->log_buf, byte_xs(tmp));
                }
        } else {
                rb_str_buf_append(c->log_buf, byte_xs(tmp));
        }
}

static void append_request(struct clogger *c)
{
        VALUE tmp;

        /* REQUEST_METHOD doesn't need escaping, Rack::Lint governs it */
        tmp = rb_hash_aref(c->env, g_REQUEST_METHOD);
        if (!NIL_P(tmp))
                rb_str_buf_append(c->log_buf, tmp);

        rb_str_buf_append(c->log_buf, g_space);

        append_request_uri(c);

        /* HTTP_VERSION can be injected by malicious clients */
        tmp = rb_hash_aref(c->env, g_HTTP_VERSION);
        if (!NIL_P(tmp)) {
                rb_str_buf_append(c->log_buf, g_space);
                rb_str_buf_append(c->log_buf, byte_xs(tmp));
        }
}

static void append_request_length(struct clogger *c)
{
        VALUE tmp = rb_hash_aref(c->env, g_rack_input);
        if (NIL_P(tmp)) {
                rb_str_buf_append(c->log_buf, g_dash);
        } else {
                tmp = rb_funcall(tmp, size_id, 0);
                rb_str_buf_append(c->log_buf, rb_funcall(tmp, to_s_id, 0));
        }
}

static void
append_time(struct clogger *c, enum clogger_opcode op, VALUE fmt, VALUE buf)
{
        char *buf_ptr = RSTRING_PTR(buf);
        size_t buf_size = RSTRING_LEN(buf) + 1; /* "\0" */
        size_t nr;
        struct tm tmp;
        time_t t = time(NULL);

        if (op == CL_OP_TIME_LOCAL)
                localtime_r(&t, &tmp);
        else if (op == CL_OP_TIME_UTC)
                gmtime_r(&t, &tmp);
        else
                assert(0 && "unknown op");

        nr = strftime(buf_ptr, buf_size, RSTRING_PTR(fmt), &tmp);
        assert(nr < buf_size && "time format too small!");
        rb_str_buf_cat(c->log_buf, buf_ptr, nr);
}

static void append_pid(struct clogger *c)
{
        char buf[(sizeof(pid_t) * 8) / 3 + 1];
        int nr = snprintf(buf, sizeof(buf), "%d", (int)getpid());

        assert(nr > 0 && nr < (int)sizeof(buf));
        rb_str_buf_cat(c->log_buf, buf, nr);
}

static void append_eval(struct clogger *c, VALUE str)
{
        int state = -1;
        VALUE rv = rb_eval_string_protect(RSTRING_PTR(str), &state);

        rv = state == 0 ? rb_obj_as_string(rv) : g_dash;
        rb_str_buf_append(c->log_buf, rv);
}

static void append_cookie(struct clogger *c, VALUE key)
{
        VALUE cookie;

        if (c->cookies == Qfalse)
                c->cookies = rb_hash_aref(c->env, g_rack_request_cookie_hash);

        if (NIL_P(c->cookies)) {
                cookie = g_dash;
        } else {
                cookie = rb_hash_aref(c->cookies, key);
                if (NIL_P(cookie))
                        cookie = g_dash;
        }
        rb_str_buf_append(c->log_buf, cookie);
}

static void append_request_env(struct clogger *c, VALUE key)
{
        VALUE tmp = rb_hash_aref(c->env, key);

        tmp = NIL_P(tmp) ? g_dash : byte_xs(tmp);
        rb_str_buf_append(c->log_buf, tmp);
}

static void append_response(struct clogger *c, VALUE key)
{
        VALUE v;

        assert(rb_obj_is_kind_of(c->headers, cHeaderHash) && "not HeaderHash");

        v = rb_funcall(c->headers, sq_brace_id, 1, key);
        v = NIL_P(v) ? g_dash : byte_xs(v);
        rb_str_buf_append(c->log_buf, v);
}

static void special_var(struct clogger *c, enum clogger_special var)
{
        switch (var) {
        case CL_SP_body_bytes_sent:
                append_body_bytes_sent(c);
                break;
        case CL_SP_status:
                append_status(c);
                break;
        case CL_SP_request:
                append_request(c);
                break;
        case CL_SP_request_length:
                append_request_length(c);
                break;
        case CL_SP_response_length:
                if (c->body_bytes_sent == 0)
                        rb_str_buf_append(c->log_buf, g_dash);
                else
                        append_body_bytes_sent(c);
                break;
        case CL_SP_ip:
                append_ip(c);
                break;
        case CL_SP_pid:
                append_pid(c);
                break;
        case CL_SP_request_uri:
                append_request_uri(c);
        }
}

static VALUE cwrite(struct clogger *c)
{
        const VALUE ops = c->fmt_ops;
        const VALUE *ary = RARRAY_PTR(ops);
        long i = RARRAY_LEN(ops);
        VALUE dst = c->log_buf;

        rb_str_set_len(dst, 0);

        for (; --i >= 0; ary++) {
                const VALUE *op = RARRAY_PTR(*ary);
                enum clogger_opcode opcode = FIX2INT(op[0]);

                switch (opcode) {
                case CL_OP_LITERAL:
                        rb_str_buf_append(dst, op[1]);
                        break;
                case CL_OP_REQUEST:
                        append_request_env(c, op[1]);
                        break;
                case CL_OP_RESPONSE:
                        append_response(c, op[1]);
                        break;
                case CL_OP_SPECIAL:
                        special_var(c, FIX2INT(op[1]));
                        break;
                case CL_OP_EVAL:
                        append_eval(c, op[1]);
                        break;
                case CL_OP_TIME_LOCAL:
                case CL_OP_TIME_UTC:
                        append_time(c, opcode, op[1], op[2]);
                        break;
                case CL_OP_REQUEST_TIME:
                        append_request_time_fmt(c, op);
                        break;
                case CL_OP_TIME:
                        append_time_fmt(c, op);
                        break;
                case CL_OP_COOKIE:
                        append_cookie(c, op[1]);
                        break;
                }
        }

        if (c->fd >= 0) {
                write_full(c->fd, RSTRING_PTR(dst), RSTRING_LEN(dst));
        } else {
                VALUE logger = c->logger;

                if (NIL_P(logger))
                        logger = rb_hash_aref(c->env, g_rack_errors);
                rb_funcall(logger, ltlt_id, 1, dst);
        }

        return Qnil;
}

static VALUE clogger_write(VALUE self)
{
        return cwrite(clogger_get(self));
}

static void init_logger(struct clogger *c, VALUE path)
{
        ID id;

        if (!NIL_P(path) && !NIL_P(c->logger))
                rb_raise(rb_eArgError, ":logger and :path are independent");
        if (!NIL_P(path)) {
                VALUE ab = rb_str_new2("ab");
                id = rb_intern("open");
                c->logger = rb_funcall(rb_cFile, id, 2, path, ab);
        }

        id = rb_intern("sync=");
        if (rb_respond_to(c->logger, id))
                rb_funcall(c->logger, id, 1, Qtrue);

        id = rb_intern("fileno");
        if (rb_respond_to(c->logger, id))
                c->fd = raw_fd(rb_funcall(c->logger, id, 0));
}

/**
 * call-seq:
 *   Clogger.new(app, :logger => $stderr, :format => string) => obj
 *
 * Creates a new Clogger object that wraps +app+.  +:logger+ may
 * be any object that responds to the "<<" method with a string argument.
 * If +:logger:+ is a string, it will be treated as a path to a
 * File that will be opened in append mode.
 */
static VALUE clogger_init(int argc, VALUE *argv, VALUE self)
{
        struct clogger *c = clogger_get(self);
        VALUE o = Qnil;
        VALUE fmt = rb_const_get(mFormat, rb_intern("Common"));

        rb_scan_args(argc, argv, "11", &c->app, &o);
        c->fd = -1;
        c->logger = Qnil;
        c->reentrant = -1; /* auto-detect */

        if (TYPE(o) == T_HASH) {
                VALUE tmp;

                tmp = rb_hash_aref(o, ID2SYM(rb_intern("path")));
                c->logger = rb_hash_aref(o, ID2SYM(rb_intern("logger")));
                init_logger(c, tmp);

                tmp = rb_hash_aref(o, ID2SYM(rb_intern("format")));
                if (!NIL_P(tmp))
                        fmt = tmp;

                tmp = rb_hash_aref(o, ID2SYM(rb_intern("reentrant")));
                switch (TYPE(tmp)) {
                case T_TRUE:
                        c->reentrant = 1;
                        break;
                case T_FALSE:
                        c->reentrant = 0;
                case T_NIL:
                        break;
                default:
                        rb_raise(rb_eArgError, ":reentrant must be boolean");
                }
        }

        init_buffers(c);
        c->fmt_ops = rb_funcall(self, rb_intern("compile_format"), 2, fmt, o);

        if (Qtrue == rb_funcall(self, rb_intern("need_response_headers?"),
                                1, c->fmt_ops))
                c->need_resp = 1;
        if (Qtrue == rb_funcall(self, rb_intern("need_wrap_body?"),
                                1, c->fmt_ops))
                c->wrap_body = 1;

        return self;
}

static VALUE body_iter_i(VALUE str, VALUE self)
{
        struct clogger *c = clogger_get(self);

        str = rb_obj_as_string(str);
        c->body_bytes_sent += RSTRING_LEN(str);

        return rb_yield(str);
}

static VALUE body_close(VALUE self)
{
        struct clogger *c = clogger_get(self);

        if (rb_respond_to(c->body, close_id))
                return rb_funcall(c->body, close_id, 0);
        return Qnil;
}

/**
 * call-seq:
 *   clogger.each { |part| socket.write(part) }
 *
 * Delegates the body#each call to the underlying +body+ object
 * while tracking the number of bytes yielded.  This will log
 * the request.
 */
static VALUE clogger_each(VALUE self)
{
        struct clogger *c = clogger_get(self);

        rb_need_block();
        c->body_bytes_sent = 0;
        rb_iterate(rb_each, c->body, body_iter_i, self);

        return self;
}

/**
 * call-seq:
 *   clogger.close
 *
 * Delegates the body#close call to the underlying +body+ object.
 * This is only used when Clogger is wrapping the +body+ of a Rack
 * response and should be automatically called by the web server.
 */
static VALUE clogger_close(VALUE self)
{

        return rb_ensure(body_close, self, clogger_write, self);
}

/* :nodoc: */
static VALUE clogger_fileno(VALUE self)
{
        struct clogger *c = clogger_get(self);

        return c->fd < 0 ? Qnil : INT2NUM(c->fd);
}

static VALUE ccall(struct clogger *c, VALUE env)
{
        VALUE rv;

        clock_gettime(hopefully_CLOCK_MONOTONIC, &c->ts_start);
        c->env = env;
        c->cookies = Qfalse;
        rv = rb_funcall(c->app, call_id, 1, env);
        if (TYPE(rv) == T_ARRAY && RARRAY_LEN(rv) == 3) {
                VALUE *tmp = RARRAY_PTR(rv);

                c->status = tmp[0];
                c->headers = tmp[1];
                c->body = tmp[2];

                rv = rb_ary_new4(3, tmp);
                if (c->need_resp &&
                    ! rb_obj_is_kind_of(tmp[1], cHeaderHash)) {
                        c->headers = rb_funcall(cHeaderHash, new_id, 1, tmp[1]);
                        rb_ary_store(rv, 1, c->headers);
                }
        } else {
                volatile VALUE tmp = rb_inspect(rv);

                c->status = INT2FIX(500);
                c->headers = c->body = rb_ary_new();
                cwrite(c);
                rb_raise(rb_eTypeError,
                         "app response not a 3 element Array: %s",
                         RSTRING_PTR(tmp));
        }

        return rv;
}

/*
 * call-seq:
 *   clogger.call(env) => [ status, headers, body ]
 *
 * calls the wrapped Rack application with +env+, returns the
 * [status, headers, body ] tuplet required by Rack.
 */
static VALUE clogger_call(VALUE self, VALUE env)
{
        struct clogger *c = clogger_get(self);
        VALUE rv;

        env = rb_check_convert_type(env, T_HASH, "Hash", "to_hash");

        if (c->wrap_body) {
                if (c->reentrant < 0) {
                        VALUE tmp = rb_hash_aref(env, g_rack_multithread);
                        c->reentrant = Qfalse == tmp ? 0 : 1;
                }
                if (c->reentrant) {
                        self = rb_obj_dup(self);
                        c = clogger_get(self);
                }

                rv = ccall(c, env);
                assert(!OBJ_FROZEN(rv) && "frozen response array");
                rb_ary_store(rv, 2, self);

                return rv;
        }

        rv = ccall(c, env);
        cwrite(c);

        return rv;
}

static void duplicate_buffers(VALUE ops)
{
        long i = RARRAY_LEN(ops);
        VALUE *ary = RARRAY_PTR(ops);

        for ( ; --i >= 0; ary++) {
                VALUE *op = RARRAY_PTR(*ary);
                enum clogger_opcode opcode = FIX2INT(op[0]);

                if (opcode == CL_OP_TIME_LOCAL || opcode == CL_OP_TIME_UTC) {
                        Check_Type(op[2], T_STRING);
                        op[2] = rb_str_dup(op[2]);
                        rb_str_modify(op[2]); /* trigger copy-on-write */
                }
        }
}

/* :nodoc: */
static VALUE clogger_init_copy(VALUE clone, VALUE orig)
{
        struct clogger *a = clogger_get(orig);
        struct clogger *b = clogger_get(clone);

        memcpy(b, a, sizeof(struct clogger));
        init_buffers(b);
        duplicate_buffers(b->fmt_ops);

        return clone;
}

#define CONST_GLOBAL_STR2(var, val) do { \
        g_##var = rb_obj_freeze(rb_str_new(val, sizeof(val) - 1)); \
        rb_global_variable(&g_##var); \
} while (0)

#define CONST_GLOBAL_STR(val) CONST_GLOBAL_STR2(val, #val)

/*
 * call-seq:
 *   clogger.respond_to?(:to_path) => true or false
 *   clogger.respond_to?(:close)  => true
 *
 * used to delegate +:to_path+ checks for Rack webservers that optimize
 * static file serving
 */
static VALUE respond_to(VALUE self, VALUE method)
{
        struct clogger *c = clogger_get(self);
        ID id = rb_to_id(method);

        if (close_id == id)
                return Qtrue;
        return rb_respond_to(c->body, id);
}

/*
 * call-seq:
 *   clogger.to_path
 *
 * used to proxy +:to_path+ method calls to the wrapped response body.
 */
static VALUE to_path(VALUE self)
{
        struct clogger *c = clogger_get(self);
        VALUE path = rb_funcall(c->body, to_path_id, 0);
        struct stat sb;
        int rv;
        unsigned devfd;
        const char *cpath = StringValueCStr(path);

        /* try to avoid an extra path lookup  */
        if (rb_respond_to(c->body, to_io_id))
                rv = fstat(my_fileno(c->body), &sb);
        /*
         * Rainbows! can use "/dev/fd/%u" in to_path output to avoid
         * extra open() syscalls, too.
         */
        else if (sscanf(cpath, "/dev/fd/%u", &devfd) == 1)
                rv = fstat((int)devfd, &sb);
        else
                rv = stat(cpath, &sb);

        /*
         * calling this method implies the web server will bypass
         * the each method where body_bytes_sent is calculated,
         * so we stat and set that value here.
         */
        c->body_bytes_sent = rv == 0 ? sb.st_size : 0;
        return path;
}

/*
 * call-seq:
 *   clogger.to_io
 *
 * used to proxy +:to_io+ method calls to the wrapped response body.
 */
static VALUE to_io(VALUE self)
{
        struct clogger *c = clogger_get(self);
        struct stat sb;
        VALUE io = rb_convert_type(c->body, T_FILE, "IO", "to_io");

        if (fstat(my_fileno(io), &sb) == 0)
                c->body_bytes_sent = sb.st_size;

        return io;
}

/* :nodoc: */
static VALUE body(VALUE self)
{
        return clogger_get(self)->body;
}

void Init_clogger_ext(void)
{
        VALUE tmp;

        check_clock();

        ltlt_id = rb_intern("<<");
        call_id = rb_intern("call");
        each_id = rb_intern("each");
        close_id = rb_intern("close");
        to_i_id = rb_intern("to_i");
        to_s_id = rb_intern("to_s");
        size_id = rb_intern("size");
        sq_brace_id = rb_intern("[]");
        new_id = rb_intern("new");
        to_path_id = rb_intern("to_path");
        to_io_id = rb_intern("to_io");
        respond_to_id = rb_intern("respond_to?");
        cClogger = rb_define_class("Clogger", rb_cObject);
        mFormat = rb_define_module_under(cClogger, "Format");
        rb_define_alloc_func(cClogger, clogger_alloc);
        rb_define_method(cClogger, "initialize", clogger_init, -1);
        rb_define_method(cClogger, "initialize_copy", clogger_init_copy, 1);
        rb_define_method(cClogger, "call", clogger_call, 1);
        rb_define_method(cClogger, "each", clogger_each, 0);
        rb_define_method(cClogger, "close", clogger_close, 0);
        rb_define_method(cClogger, "fileno", clogger_fileno, 0);
        rb_define_method(cClogger, "wrap_body?", clogger_wrap_body, 0);
        rb_define_method(cClogger, "reentrant?", clogger_reentrant, 0);
        rb_define_method(cClogger, "to_path", to_path, 0);
        rb_define_method(cClogger, "to_io", to_io, 0);
        rb_define_method(cClogger, "respond_to?", respond_to, 1);
        rb_define_method(cClogger, "body", body, 0);
        CONST_GLOBAL_STR(REMOTE_ADDR);
        CONST_GLOBAL_STR(HTTP_X_FORWARDED_FOR);
        CONST_GLOBAL_STR(REQUEST_METHOD);
        CONST_GLOBAL_STR(PATH_INFO);
        CONST_GLOBAL_STR(QUERY_STRING);
        CONST_GLOBAL_STR(REQUEST_URI);
        CONST_GLOBAL_STR(HTTP_VERSION);
        CONST_GLOBAL_STR2(rack_errors, "rack.errors");
        CONST_GLOBAL_STR2(rack_input, "rack.input");
        CONST_GLOBAL_STR2(rack_multithread, "rack.multithread");
        CONST_GLOBAL_STR2(dash, "-");
        CONST_GLOBAL_STR2(space, " ");
        CONST_GLOBAL_STR2(question_mark, "?");
        CONST_GLOBAL_STR2(rack_request_cookie_hash, "rack.request.cookie_hash");

        tmp = rb_const_get(rb_cObject, rb_intern("Rack"));
        tmp = rb_const_get(tmp, rb_intern("Utils"));
        cHeaderHash = rb_const_get(tmp, rb_intern("HeaderHash"));
}