Add cairo-sphinx utility for regression analysis

sphinx is an alternate version of the current cairo-test-trace. It's
purpose is to replay a live application (which may just be a replay of a
trace) against a backend and its reference. The improvement over the
original cairo-test-trace is that the reference backend may be from an
older version of cairo.

4 files changed, 1826 insertions, 0 deletions

diff --git a/util/cairo-sphinx/.gitignore b/util/cairo-sphinx/.gitignore
new file mode 100644
index 00000000..56ecd5de
--- /dev/null
+++ b/util/cairo-sphinx/.gitignore
@@ -0,0 +1 @@
+cairo-sphinx
diff --git a/util/cairo-sphinx/Makefile.am b/util/cairo-sphinx/Makefile.am
new file mode 100644
index 00000000..845888c7
--- /dev/null
+++ b/util/cairo-sphinx/Makefile.am
@@ -0,0 +1,40 @@
+cairolibdir = $(libdir)/cairo
+
+cairolib_LTLIBRARIES = cairo-sphinx.la
+bin_PROGRAMS = cairo-sphinx
+
+AM_CPPFLAGS = -I$(top_srcdir)/src \
+	      -I$(top_builddir)/src \
+	      -I$(top_srcdir)/boilerplate \
+	      -I$(top_srcdir)/util/cairo-script
+
+cairo_sphinx_la_SOURCES = fdr.c
+cairo_sphinx_la_CPPFLAGS = $(AM_CPPFLAGS)
+cairo_sphinx_la_CFLAGS = $(CAIRO_CFLAGS)
+cairo_sphinx_la_LDFLAGS = -module -no-undefined
+cairo_sphinx_la_LIBADD = -ldl
+
+cairo_sphinx_SOURCES = sphinx.c
+cairo_sphinx_CPPFLAGS = $(AM_CPPFLAGS) -DLIBDIR="\"$(cairolibdir)\""
+cairo_sphinx_CFLAGS = $(CAIRO_CFLAGS) $(glib_CFLAGS)
+cairo_sphinx_LDADD = \
+        $(top_builddir)/util/cairo-script/libcairo-script-interpreter.la \
+        $(top_builddir)/boilerplate/libcairoboilerplate.la	\
+	$(top_builddir)/src/libcairo.la 			\
+	$(glib_LIBS) 						\
+	$(CAIRO_LDADD)						\
+	-lrt
+cairo_sphinx_DEPENDENCIES = \
+        $(top_builddir)/util/cairo-script/libcairo-script-interpreter.la \
+        $(top_builddir)/boilerplate/libcairoboilerplate.la	\
+	$(top_builddir)/src/libcairo.la
+
+# Install rules to rebuild the libraries and add explicit dependencies
+$(top_builddir)/boilerplate/libcairoboilerplate.la: $(top_builddir)/src/libcairo.la
+	cd $(top_builddir)/boilerplate && $(MAKE) $(AM_MAKEFLAGS) libcairoboilerplate.la
+
+$(top_builddir)/src/libcairo.la:
+	cd $(top_builddir)/src && $(MAKE) $(AM_MAKEFLAGS) libcairo.la
+
+$(top_builddir)/util/cairo-script/libcairo-script-interpreter.la: $(top_builddir)/src/libcairo.la
+	cd $(top_builddir)/util/cairo-script && $(MAKE) $(AM_MAKEFLAGS) libcairo-script-interpreter.la
diff --git a/util/cairo-sphinx/fdr.c b/util/cairo-sphinx/fdr.c
new file mode 100644
index 00000000..993baba3
--- /dev/null
+++ b/util/cairo-sphinx/fdr.c
@@ -0,0 +1,260 @@
+/* cairo-fdr - a 'flight data recorder', a black box, for cairo
+ *
+ * Copyright © 2009 Chris Wilson
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define _GNU_SOURCE
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <cairo.h>
+#include <cairo-script.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <dlfcn.h>
+
+static void *_dlhandle = RTLD_NEXT;
+#define DLCALL(name, args...) ({ \
+    static typeof (&name) name##_real; \
+    if (name##_real == NULL) { \
+	name##_real = dlsym (_dlhandle, #name); \
+	if (name##_real == NULL && _dlhandle == RTLD_NEXT) { \
+	    _dlhandle = dlopen ("libcairo.so", RTLD_LAZY); \
+	    name##_real = dlsym (_dlhandle, #name); \
+	    assert (name##_real != NULL); \
+	} \
+    } \
+    (*name##_real) (args);  \
+})
+
+static cairo_script_context_t *fdr_context;
+static const cairo_user_data_key_t fdr_key;
+
+static void
+fdr_get_extents (cairo_surface_t *surface,
+		 cairo_rectangle_t *extents)
+{
+    cairo_t *cr;
+
+    cr = DLCALL (cairo_create, surface);
+    DLCALL (cairo_clip_extents, cr,
+	    &extents->x, &extents->y, &extents->width, &extents->height);
+    DLCALL (cairo_destroy, cr);
+
+    extents->width -= extents->x;
+    extents->height -= extents->y;
+}
+
+static void
+fdr_surface_destroy (void *surface)
+{
+    DLCALL (cairo_surface_destroy, surface);
+}
+
+static void
+fdr_surface_reference (void *surface)
+{
+    DLCALL (cairo_surface_reference, surface);
+}
+
+static cairo_surface_t *
+fdr_surface_get_tee (cairo_surface_t *surface)
+{
+    return DLCALL (cairo_surface_get_user_data, surface, &fdr_key);
+}
+
+static cairo_surface_t *
+fdr_tee_surface_index (cairo_surface_t *surface, int index)
+{
+    return DLCALL (cairo_tee_surface_index, surface, index);
+}
+
+static cairo_status_t
+fdr_write (void *closure, const unsigned char *data, unsigned int len)
+{
+    int fd = (int) (intptr_t) closure;
+    while (len) {
+	int ret = write (fd, data, len);
+	if (ret < 0) {
+	    switch (errno) {
+	    case EAGAIN:
+	    case EINTR:
+		continue;
+	    default:
+		return CAIRO_STATUS_WRITE_ERROR;
+	    }
+	} else if (ret == 0) {
+	    return CAIRO_STATUS_WRITE_ERROR;
+	} else {
+	    data += ret;
+	    len -= ret;
+	}
+    }
+    return CAIRO_STATUS_SUCCESS;
+}
+
+cairo_t *
+cairo_create (cairo_surface_t *surface)
+{
+    cairo_surface_t *tee;
+
+    tee = fdr_surface_get_tee (surface);
+    if (tee == NULL) {
+	cairo_surface_t *script;
+	cairo_rectangle_t extents;
+	cairo_content_t content;
+
+	if (fdr_context == NULL) {
+	    const char *env = getenv ("CAIRO_SPHINX_FD");
+	    int fd = env ? atoi (env) : 1;
+	    fdr_context = DLCALL (cairo_script_context_create_for_stream,
+				  fdr_write, (void *) (intptr_t) fd);
+	}
+
+	fdr_get_extents (surface, &extents);
+	content = DLCALL (cairo_surface_get_content, surface);
+
+	tee = DLCALL (cairo_tee_surface_create, surface);
+	script = DLCALL (cairo_script_surface_create,
+			 fdr_context, content, extents.width, extents.height);
+	DLCALL (cairo_tee_surface_append, tee, script);
+
+	DLCALL (cairo_surface_set_user_data, surface,
+		&fdr_key, tee, fdr_surface_destroy);
+    }
+
+    return DLCALL (cairo_create, tee);
+}
+
+static void
+fdr_remove_tee (cairo_surface_t *surface)
+{
+    fdr_surface_reference (surface);
+    DLCALL (cairo_surface_set_user_data, surface, &fdr_key, NULL, NULL);
+    fdr_surface_destroy (surface);
+}
+
+void
+cairo_destroy (cairo_t *cr)
+{
+    cairo_surface_t *tee;
+
+    tee = DLCALL (cairo_get_target, cr);
+    DLCALL (cairo_destroy, cr);
+
+    if (DLCALL (cairo_surface_get_reference_count, tee) == 1)
+	fdr_remove_tee (fdr_tee_surface_index (tee, 0));
+}
+
+void
+cairo_pattern_destroy (cairo_pattern_t *pattern)
+{
+    if (DLCALL (cairo_pattern_get_type, pattern) == CAIRO_PATTERN_TYPE_SURFACE) {
+	cairo_surface_t *surface;
+
+	if (DLCALL (cairo_pattern_get_surface, pattern, &surface) == CAIRO_STATUS_SUCCESS &&
+	    DLCALL (cairo_surface_get_type, surface) == CAIRO_SURFACE_TYPE_TEE &&
+	    DLCALL (cairo_surface_get_reference_count, surface) == 2)
+	{
+	    fdr_remove_tee (fdr_tee_surface_index (surface, 0));
+	}
+    }
+
+    DLCALL (cairo_pattern_destroy, pattern);
+}
+
+cairo_surface_t *
+cairo_get_target (cairo_t *cr)
+{
+    cairo_surface_t *tee;
+
+    tee = DLCALL (cairo_get_target, cr);
+    return fdr_tee_surface_index (tee, 0);
+}
+
+cairo_surface_t *
+cairo_get_group_target (cairo_t *cr)
+{
+    cairo_surface_t *tee;
+
+    tee = DLCALL (cairo_get_group_target, cr);
+    return fdr_tee_surface_index (tee, 0);
+}
+
+cairo_pattern_t *
+cairo_pattern_create_for_surface (cairo_surface_t *surface)
+{
+    cairo_surface_t *tee;
+
+    tee = fdr_surface_get_tee (surface);
+    if (tee != NULL)
+	surface = tee;
+
+    return DLCALL (cairo_pattern_create_for_surface, surface);
+}
+
+cairo_status_t
+cairo_pattern_get_surface (cairo_pattern_t *pattern,
+			   cairo_surface_t **surface)
+{
+    cairo_status_t status;
+    cairo_surface_t *tee;
+
+    status = DLCALL (cairo_pattern_get_surface, pattern, surface);
+    if (status != CAIRO_STATUS_SUCCESS)
+	return status;
+
+    tee = fdr_surface_get_tee (*surface);
+    if (tee != NULL)
+	*surface = tee;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+void
+cairo_set_source_surface (cairo_t *cr,
+			  cairo_surface_t *surface,
+			  double x, double y)
+{
+    cairo_surface_t *tee;
+
+    tee = fdr_surface_get_tee (surface);
+    if (tee != NULL)
+	surface = tee;
+
+    DLCALL (cairo_set_source_surface, cr, surface, x, y);
+}
+
+cairo_surface_t *
+cairo_surface_create_similar (cairo_surface_t *surface,
+			      cairo_content_t content,
+			      int width, int height)
+{
+    cairo_surface_t *tee;
+
+    tee = fdr_surface_get_tee (surface);
+    if (tee != NULL)
+	surface = tee;
+
+    return DLCALL (cairo_surface_create_similar,
+		   surface, content, width, height);
+}
diff --git a/util/cairo-sphinx/sphinx.c b/util/cairo-sphinx/sphinx.c
new file mode 100644
index 00000000..d6ccfc74
--- /dev/null
+++ b/util/cairo-sphinx/sphinx.c
@@ -0,0 +1,1525 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <errno.h>
+#include <assert.h>
+#include <pthread.h>
+
+#include <cairo.h>
+#include <cairo-script.h>
+#include <cairo-script-interpreter.h>
+#include <cairo-boilerplate.h>
+
+#include <glib.h> /* for checksumming */
+
+#define DATA_SIZE (256 << 20)
+#define SHM_PATH_XXX "/shmem-cairo-sphinx"
+
+struct client {
+    int sk;
+    const cairo_boilerplate_target_t *target;
+    cairo_surface_t *surface;
+    void *base;
+
+    cairo_script_interpreter_t *csi;
+    struct context_closure {
+	struct context_closure *next;
+	unsigned long id;
+	cairo_t *context;
+	cairo_surface_t *surface;
+	cairo_surface_t *original;
+    } *contexts;
+
+    unsigned long context_id;
+};
+
+struct surface_tag {
+    long width, height;
+};
+static const cairo_user_data_key_t surface_tag;
+
+static int
+client_socket (const char *socket_path);
+
+static int
+writen (int fd, const void *ptr, int len)
+{
+#if 1
+    const uint8_t *data = ptr;
+    while (len) {
+	int ret = write (fd, data, len);
+	if (ret < 0) {
+	    switch (errno) {
+	    case EAGAIN:
+	    case EINTR:
+		continue;
+	    default:
+		return FALSE;
+	    }
+	} else if (ret == 0) {
+	    return FALSE;
+	} else {
+	    data += ret;
+	    len -= ret;
+	}
+    }
+    return TRUE;
+#else
+    int ret = send (fd, ptr, len, 0);
+    return ret == len;
+#endif
+}
+
+static int
+readn (int fd, void *ptr, int len)
+{
+#if 0
+    uint8_t *data = ptr;
+    while (len) {
+	int ret = read (fd, data, len);
+	if (ret < 0) {
+	    switch (errno) {
+	    case EAGAIN:
+	    case EINTR:
+		continue;
+	    default:
+		return FALSE;
+	    }
+	} else if (ret == 0) {
+	    return FALSE;
+	} else {
+	    data += ret;
+	    len -= ret;
+	}
+    }
+    return TRUE;
+#else
+    int ret = recv (fd, ptr, len, MSG_WAITALL);
+    return ret == len;
+#endif
+}
+static int
+open_devnull_to_fd (int want_fd, int flags)
+{
+    int error;
+    int got_fd;
+
+    close (want_fd);
+
+    got_fd = open("/dev/null", flags | O_CREAT, 0700);
+    if (got_fd == -1)
+        return -1;
+
+    error = dup2 (got_fd, want_fd);
+    close (got_fd);
+
+    return error;
+}
+
+static int
+daemonize (void)
+{
+    void (*oldhup) (int);
+
+    /* Let the parent go. */
+    switch (fork ()) {
+    case -1: return -1;
+    case 0: break;
+    default: _exit (0);
+    }
+
+    /* Become session leader. */
+    if (setsid () == -1)
+	return -1;
+
+    /* Refork to yield session leadership. */
+    oldhup = signal (SIGHUP, SIG_IGN);
+
+    switch (fork ()) {		/* refork to yield session leadership. */
+    case -1: return -1;
+    case 0: break;
+    default: _exit (0);
+    }
+
+    signal (SIGHUP, oldhup);
+
+    /* Establish stdio. */
+    if (open_devnull_to_fd (0, O_RDONLY) == -1)
+	return -1;
+    if (open_devnull_to_fd (1, O_WRONLY | O_APPEND) == -1)
+	return -1;
+    if (dup2 (1, 2) == -1)
+	return -1;
+
+    return 0;
+}
+
+static int
+server_socket (const char *socket_path)
+{
+    long flags;
+    struct sockaddr_un addr;
+    int sk;
+
+    unlink (socket_path);
+
+    sk = socket (PF_UNIX, SOCK_STREAM, 0);
+    if (sk == -1)
+	return -1;
+
+    memset (&addr, 0, sizeof (addr));
+    addr.sun_family = AF_UNIX;
+    strcpy (addr.sun_path, socket_path);
+    if (bind (sk, (struct sockaddr *) &addr, sizeof (addr)) == -1) {
+	close (sk);
+	return -1;
+    }
+
+    flags = fcntl (sk, F_GETFL);
+    if (flags == -1 || fcntl (sk, F_SETFL, flags | O_NONBLOCK) == -1) {
+	close (sk);
+	return -1;
+    }
+
+    if (listen (sk, 5) == -1) {
+	close (sk);
+	return -1;
+    }
+
+    return sk;
+}
+
+static int
+readline (int fd, char *line, int max)
+{
+    int len = 0;
+    do {
+	int ret = read (fd, &line[len], 1);
+	if (ret <= 0)
+	    return -1;
+    } while (line[len] != '\n' && ++len < max);
+    line[len] = '\0';
+    return len;
+}
+
+struct clients {
+    int count, size;
+    int complete;
+
+    cairo_surface_t *meta;
+    unsigned long serial;
+
+    struct client_info {
+	int sk;
+	int trace;
+	unsigned long image_serial;
+	cairo_surface_t *image;
+	char *name;
+	char *target;
+	char *reference;
+
+	uint8_t *out_buf;
+	int out_len;
+	int out_size;
+    } *clients;
+    const char *shm_path;
+    unsigned long offset;
+    uint8_t *base;
+};
+
+static void *
+clients_shm (const char *shm_path)
+{
+    void *base;
+    int fd;
+
+    shm_unlink (shm_path);
+    fd = shm_open (shm_path, O_RDWR | O_EXCL | O_CREAT, 0777);
+    if (fd == -1)
+	return MAP_FAILED;
+
+    if (ftruncate (fd, DATA_SIZE) == -1) {
+	close (fd);
+	return MAP_FAILED;
+    }
+
+    base = mmap (NULL, DATA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    close (fd);
+
+    return base;
+}
+
+static int
+clients_init (struct clients *clients)
+{
+    clients->count = 0;
+    clients->complete = 0;
+    clients->size = 4;
+    clients->clients = xmalloc (clients->size * sizeof (struct client_info));
+
+    clients->shm_path = SHM_PATH_XXX;
+    clients->base = clients_shm (clients->shm_path);
+    if (clients->base == MAP_FAILED)
+	return -1;
+    clients->offset = 0;
+
+    clients->meta = NULL;
+    clients->serial = 0;
+
+    return 0;
+}
+
+static void
+clients_add_command (struct clients *clients, int fd, char *info)
+{
+    struct client_info *c;
+    char buf[1024];
+    int len;
+    char *str;
+
+    if (clients->count == clients->size) {
+	clients->size *= 2;
+	clients->clients = xrealloc (clients->clients,
+				     clients->size * sizeof (struct client_info));
+    }
+
+    c = &clients->clients[clients->count++];
+    c->sk = fd;
+    c->trace = -1;
+    c->image_serial = 0;
+    c->image = NULL;
+    c->name = c->target = c->reference = NULL;
+
+    c->out_size = 8192;
+    c->out_buf = xmalloc (c->out_size);
+    c->out_len = 0;
+
+    str = strstr (info, "name=");
+    if (str != NULL) {
+	char *sp = strchr (str + 5, ' ');
+	int len;
+	if (sp)
+	    len = sp - str - 5;
+	else
+	    len = strlen (str + 5);
+	c->name = xmalloc (len + 1);
+	memcpy (c->name, str + 5, len);
+	c->name[len] = '\0';
+    }
+
+    str = strstr (info, "target=");
+    if (str != NULL) {
+	char *sp = strchr (str + 7, ' ');
+	int len;
+	if (sp)
+	    len = sp - str - 7;
+	else
+	    len = strlen (str + 7);
+	c->target = xmalloc (len + 1);
+	memcpy (c->target, str + 7, len);
+	c->target[len] = '\0';
+    }
+
+    str = strstr (info, "reference=");
+    if (str != NULL) {
+	char *sp = strchr (str + 10, ' ');
+	int len;
+	if (sp)
+	    len = sp - str - 10;
+	else
+	    len = strlen (str + 10);
+	c->reference = xmalloc (len + 1);
+	memcpy (c->reference, str + 10, len);
+	c->reference[len] = '\0';
+    }
+
+    len = sprintf (buf, "%s\n", clients->shm_path);
+    writen (fd, buf, len);
+}
+
+static void
+clients_add_trace (struct clients *clients, int fd, char *info)
+{
+    char *str, *sp;
+    char *name;
+    int i;
+
+    str = strstr (info, "name=");
+    assert (str != NULL);
+    sp = strchr (str + 5, ' ');
+    if (sp)
+	i = sp - str - 5;
+    else
+	i = strlen (str + 5);
+
+    name = xmalloc (i + 1);
+    memcpy (name, str + 5, i);
+    name[i] = '\0';
+
+    for (i = 0; i < clients->count; i++) {
+	struct client_info *c = &clients->clients[i];
+	if (strcmp (name, c->name) == 0) {
+	    c->trace = fd;
+	    break;
+	}
+    }
+
+    free (name);
+}
+
+static int
+clients_image (struct clients *clients, int fd, char *info)
+{
+    struct client_info *c = NULL;
+    int format, width, height, stride, size;
+    int i;
+
+    for (i = 0; i < clients->count; i++) {
+	if (clients->clients[i].sk == fd) {
+	    c = &clients->clients[i];
+	    break;
+	}
+    }
+
+    if (c == NULL)
+	return 0;
+
+    if (sscanf (info, "%lu %d %d %d %d",
+		&c->image_serial, &format, &width, &height, &stride) != 5)
+    {
+	return 0;
+    }
+
+    size = height * stride;
+    size = (size + 4095) & -4096;
+    assert (clients->offset + size <= DATA_SIZE);
+
+    c->image =
+	cairo_image_surface_create_for_data (clients->base + clients->offset,
+					     format, width, height, stride);
+
+    if (! writen (fd, &clients->offset, sizeof (clients->offset)))
+	return 0;
+
+    clients->offset += size;
+
+    return 1;
+}
+
+static int
+u8_cmp (const void *A, const void *B)
+{
+    const uint8_t *a = A, *b = B;
+    return (int) *a - (int) *b;
+}
+
+static uint8_t
+median (uint8_t *values, int count)
+{
+    qsort (values, count, 1, u8_cmp);
+    return values[count/2];
+}
+
+static uint32_t
+get_pixel32 (int x, int y, const uint8_t *data, int stride)
+{
+    return ((uint32_t *)(data + y * stride))[x];
+}
+
+static uint8_t
+get_median_32 (int x, int y, int channel,
+	       const uint8_t *data, int width, int height, int stride)
+{
+    uint8_t neighbourhood[25];
+    int cnt = 0;
+    int xx, yy;
+
+    for (yy = y - 2; yy <= y + 2; yy++) {
+	if (yy < 0)
+	    continue;
+	if (yy >= height)
+	    continue;
+
+	for (xx = x - 2; xx <= x + 2; xx++) {
+	    if (xx < 0)
+		continue;
+	    if (xx >= width)
+		continue;
+
+	    neighbourhood[cnt++] = (get_pixel32 (xx, yy, data, stride) >> (channel*8)) & 0xff;
+	}
+    }
+
+    return median (neighbourhood, cnt);
+}
+
+static uint8_t
+get_pixel8 (int x, int y, const uint8_t *data, int stride)
+{
+    return data[y * stride + x];
+}
+
+static uint8_t
+get_median_8 (int x, int y, const uint8_t *data, int width, int height, int stride)
+{
+    uint8_t neighbourhood[25];
+    int cnt = 0;
+    int xx, yy;
+
+    for (yy = y - 2; yy <= y + 2; yy++) {
+	if (yy < 0)
+	    continue;
+	if (yy >= height)
+	    continue;
+
+	for (xx = x - 2; xx <= x + 2; xx++) {
+	    if (xx < 0)
+		continue;
+	    if (xx >= width)
+		continue;
+
+	    neighbourhood[cnt++] = get_pixel8 (xx, yy, data, stride);
+	}
+    }
+
+    return median (neighbourhood, cnt);
+}
+
+static cairo_bool_t
+compare_images (cairo_surface_t *a,
+		cairo_surface_t *b)
+{
+    int width, height, stride;
+    const uint8_t *aa, *bb;
+    int x, y;
+
+    if (cairo_surface_status (a) || cairo_surface_status (b))
+	return FALSE;
+
+    if (cairo_surface_get_type (a) != cairo_surface_get_type (b))
+	return FALSE;
+
+    if (cairo_image_surface_get_format (a) != cairo_image_surface_get_format (b))
+	return FALSE;
+
+    if (cairo_image_surface_get_width (a) != cairo_image_surface_get_width (b))
+	return FALSE;
+
+    if (cairo_image_surface_get_height (a) != cairo_image_surface_get_height (b))
+	return FALSE;
+
+    if (cairo_image_surface_get_stride (a) != cairo_image_surface_get_stride (b))
+	return FALSE;
+
+
+    width = cairo_image_surface_get_width (a);
+    height = cairo_image_surface_get_height (a);
+    stride = cairo_image_surface_get_stride (a);
+
+    aa = cairo_image_surface_get_data (a);
+    bb = cairo_image_surface_get_data (b);
+    switch (cairo_image_surface_get_format (a)) {
+    case CAIRO_FORMAT_ARGB32:
+	for (y = 0; y < height; y++) {
+	    const uint32_t *ua = (uint32_t *) aa;
+	    const uint32_t *ub = (uint32_t *) bb;
+	    for (x = 0; x < width; x++) {
+		if (ua[x] != ub[x]) {
+		    int channel;
+
+		    for (channel = 0; channel < 4; channel++) {
+			unsigned va, vb, diff;
+
+			va = (ua[x] >> (channel*8)) & 0xff;
+			vb = (ub[x] >> (channel*8)) & 0xff;
+			diff = abs (va - vb);
+			if (diff > 1) {
+			    va = get_median_32 (x, y, channel, aa, width, height, stride);
+			    vb = get_median_32 (x, y, channel, bb, width, height, stride);
+			    diff = abs (va - vb);
+			    if (diff > 1)
+				return FALSE;
+			}
+		    }
+		}
+	    }
+	    aa += stride;
+	    bb += stride;
+	}
+	break;
+
+    case CAIRO_FORMAT_RGB24:
+	for (y = 0; y < height; y++) {
+	    const uint32_t *ua = (uint32_t *) aa;
+	    const uint32_t *ub = (uint32_t *) bb;
+	    for (x = 0; x < width; x++) {
+		if ((ua[x] & 0x00ffffff) != (ub[x] & 0x00ffffff)) {
+		    int channel;
+
+		    for (channel = 0; channel < 3; channel++) {
+			unsigned va, vb, diff;
+
+			va = (ua[x] >> (channel*8)) & 0xff;
+			vb = (ub[x] >> (channel*8)) & 0xff;
+			diff = abs (va - vb);
+			if (diff > 1) {
+			    va = get_median_32 (x, y, channel, aa, width, height, stride);
+			    vb = get_median_32 (x, y, channel, bb, width, height, stride);
+			    diff = abs (va - vb);
+			    if (diff > 1)
+				return FALSE;
+			}
+		    }
+		}
+	    }
+	    aa += stride;
+	    bb += stride;
+	}
+	break;
+
+    case CAIRO_FORMAT_A8:
+	for (y = 0; y < height; y++) {
+	    for (x = 0; x < width; x++) {
+		if (aa[x] != bb[x]) {
+		    unsigned diff = abs (aa[x] - bb[x]);
+		    if (diff > 1) {
+			uint8_t va, vb;
+
+			va = get_median_8 (x, y, aa, width, height, stride);
+			vb = get_median_8 (x, y, bb, width, height, stride);
+			diff = abs (va - vb);
+			if (diff > 1)
+			    return FALSE;
+		    }
+
+		}
+	    }
+	    aa += stride;
+	    bb += stride;
+	}
+	break;
+
+    case CAIRO_FORMAT_A1:
+	width /= 8;
+	for (y = 0; y < height; y++) {
+	    if (memcmp (aa, bb, width))
+		return FALSE;
+	    aa += stride;
+	    bb += stride;
+	}
+	break;
+    }
+
+    return TRUE;
+}
+
+static int
+check_images (struct clients *clients)
+{
+    int i, j;
+
+    for (i = 0; i < clients->count; i++) {
+	struct client_info *c = &clients->clients[i];
+
+	if (c->reference == NULL)
+	    continue;
+
+	for (j = 0; j < clients->count; j++) {
+	    struct client_info *ref = &clients->clients[j];
+
+	    if (strcmp (c->reference, ref->name))
+		continue;
+
+	    if (! compare_images (c->image, ref->image))
+		return 0;
+	}
+    }
+
+    return 1;
+}
+
+static gchar *
+checksum (const char *filename)
+{
+    gchar *str = NULL;
+    gchar *data;
+    gsize len;
+
+    if (g_file_get_contents (filename, &data, &len, NULL)) {
+	str = g_compute_checksum_for_data (G_CHECKSUM_SHA1, (guchar *) data, len);
+	g_free (data);
+    }
+
+    return str;
+}
+
+static void
+write_trace (struct clients *clients)
+{
+    cairo_script_context_t *ctx;
+    gchar *csum;
+    char buf[4096];
+    int i;
+
+    mkdir ("output", 0777);
+
+    ctx = cairo_script_context_create ("output/cairo-sphinx.trace");
+    cairo_script_from_meta_surface (ctx, clients->meta);
+    cairo_script_context_destroy (ctx);
+
+    csum = checksum ("output/cairo-sphinx.trace");
+
+    sprintf (buf, "output/%s.trace", csum);
+    if (! g_file_test (buf, G_FILE_TEST_EXISTS)) {
+	rename ("output/cairo-sphinx.trace", buf);
+
+	sprintf (buf, "output/%s.meta.png", csum);
+	cairo_surface_write_to_png (clients->meta, buf);
+
+	for (i = 0; i < clients->count; i++) {
+	    struct client_info *c = &clients->clients[i];
+	    if (c->image != NULL) {
+		sprintf (buf, "output/%s.%s.png", csum, c->name);
+		cairo_surface_write_to_png (c->image, buf);
+	    }
+	}
+    }
+}
+
+static void
+clients_complete (struct clients *clients, int fd)
+{
+    int i;
+
+    for (i = 0; i < clients->count; i++) {
+	if (clients->clients[i].sk == fd) {
+	    break;
+	}
+    }
+    if (i == clients->count)
+	return;
+
+    if (++clients->complete != clients->count)
+	return;
+
+    clients->offset = 0;
+    clients->complete = 0;
+
+    if (! check_images (clients))
+	write_trace (clients);
+
+    /* ack */
+    for (i = 0; i < clients->count; i++) {
+	struct client_info *c = &clients->clients[i];
+
+	cairo_surface_destroy (c->image);
+	c->image = NULL;
+
+	if (! writen (c->sk, &clients->serial, sizeof (clients->serial)))
+	    continue;
+
+	c->image_serial = 0;
+    }
+
+    clients->meta = NULL;
+    clients->serial = 0;
+}
+
+static void
+clients_meta (struct clients *clients, int fd, char *info)
+{
+    sscanf (info, "%p %lu", &clients->meta, &clients->serial);
+    clients_complete (clients, fd);
+}
+
+static void
+clients_remove (struct clients *clients, int fd)
+{
+    int i, j;
+
+    for (i = 0; i < clients->count; i++) {
+	struct client_info *c = &clients->clients[i];
+	if (c->sk == fd) {
+	    free (c->out_buf);
+	    break;
+	}
+    }
+
+    for (j = i++; i < clients->count; i++)
+	clients->clients[j] = clients->clients[i];
+
+    clients->count = j;
+}
+
+static void
+clients_send_trace (struct clients *clients,
+		    const char * const line, const int len)
+{
+    int i;
+
+    for (i = 0; i < clients->count; i++) {
+	struct client_info *c = &clients->clients[i];
+	int ret, rem = len;
+
+	if (c->trace == -1)
+	    continue;
+
+	if (c->out_len) {
+	    ret = write (c->trace, c->out_buf, c->out_len);
+	    if (ret > 0) {
+		c->out_len -= ret;
+		if (c->out_len)
+		    memmove (c->out_buf, c->out_buf + ret, c->out_len);
+	    }
+	}
+
+	if (! c->out_len) {
+	    ret = write (c->trace, line, rem);
+	    if (ret > 0)
+		rem -= ret;
+	}
+
+	if (rem) {
+	    if (c->out_len + rem > c->out_size) {
+		c->out_size *= 2;
+		c->out_buf = xrealloc (c->out_buf, c->out_size);
+	    }
+
+	    memcpy (c->out_buf + c->out_len, line, rem);
+	    c->out_len += rem;
+	}
+    }
+}
+
+static void
+clients_fini (struct clients *clients)
+{
+    shm_unlink (clients->shm_path);
+    munmap (clients->base, DATA_SIZE);
+    free (clients->clients);
+}
+
+static int
+nonblocking (int fd)
+{
+    long flags;
+
+    flags = fcntl (fd, F_GETFL);
+    if (flags == -1)
+	return -1;
+
+    return fcntl (fd, F_SETFL, flags | O_NONBLOCK);
+}
+
+static void *
+request_image (struct client *c,
+	       struct context_closure *closure,
+	       cairo_format_t format,
+	       int width, int height, int stride)
+{
+    char buf[1024];
+    unsigned long offset = -1;
+    int len;
+
+    assert (format != (cairo_format_t) -1);
+
+    len = sprintf (buf, ".image %lu %d %d %d %d\n",
+		   closure->id, format, width, height, stride);
+    writen (c->sk, buf, len);
+
+    readn (c->sk, &offset, sizeof (offset));
+    if (offset == (unsigned long) -1)
+	return NULL;
+
+    return (uint8_t *) c->base + offset;
+}
+
+static cairo_format_t
+format_for_content (cairo_content_t content)
+{
+    switch (content) {
+    case CAIRO_CONTENT_ALPHA:
+	return CAIRO_FORMAT_A8;
+    case CAIRO_CONTENT_COLOR:
+	return CAIRO_FORMAT_RGB24;
+    default:
+    case CAIRO_CONTENT_COLOR_ALPHA:
+	return CAIRO_FORMAT_ARGB32;
+    }
+}
+
+static void
+get_surface_size (cairo_surface_t *surface,
+		  int *width, int *height,
+		  cairo_format_t *format)
+{
+    if (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE) {
+	*width = cairo_image_surface_get_width (surface);
+	*height = cairo_image_surface_get_height (surface);
+	*format = cairo_image_surface_get_format (surface);
+    } else {
+	struct surface_tag *tag;
+
+	tag = cairo_surface_get_user_data (surface, &surface_tag);
+	if (tag != NULL) {
+	    *width = tag->width;
+	    *height = tag->height;
+	} else {
+	    double x0, x1, y0, y1;
+	    cairo_t *cr;
+
+	    /* presumably created using cairo_surface_create_similar() */
+	    cr = cairo_create (surface);
+	    cairo_clip_extents (cr, &x0, &y0, &x1, &y1);
+	    cairo_destroy (cr);
+
+	    tag = xmalloc (sizeof (*tag));
+	    *width = tag->width = ceil (x1 - x0);
+	    *height = tag->height = ceil (y1 - y0);
+
+	    if (cairo_surface_set_user_data (surface, &surface_tag, tag, free))
+		exit (-1);
+	}
+    }
+}
+
+
+static void
+send_surface (struct client *c,
+	      struct context_closure *closure)
+{
+    cairo_surface_t *source = closure->surface;
+    cairo_surface_t *image;
+    cairo_format_t format = (cairo_format_t) -1;
+    cairo_t *cr;
+    int width, height, stride;
+    void *data;
+    unsigned long serial;
+
+    get_surface_size (source, &width, &height, &format);
+    if (format == (cairo_format_t) -1)
+	format = format_for_content (cairo_surface_get_content (source));
+
+    stride = cairo_format_stride_for_width (format, width);
+
+    data = request_image (c, closure, format, width, height, stride);
+    if (data == NULL)
+	exit (-1);
+
+    image = cairo_image_surface_create_for_data (data,
+						 format,
+						 width, height,
+						 stride);
+    cr = cairo_create (image);
+    cairo_surface_destroy (image);
+
+    cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
+    cairo_set_source_surface (cr, source, 0, 0);
+    cairo_paint (cr);
+    cairo_destroy (cr);
+
+    /* signal completion */
+    writen (c->sk, ".complete\n", strlen (".complete\n"));
+
+    /* wait for image check */
+    serial = 0;
+    readn (c->sk, &serial, sizeof (serial));
+    if (serial != closure->id)
+	exit (-1);
+}
+
+static void
+send_meta (struct client *c,
+	   struct context_closure *closure)
+{
+    cairo_surface_t *source = closure->surface;
+    char buf[1024];
+    int len;
+    unsigned long serial;
+
+    assert (cairo_surface_get_type (source) == CAIRO_SURFACE_TYPE_META);
+    len = sprintf (buf, ".meta %p %lu\n", source, closure->id);
+    writen (c->sk, buf, len);
+
+    /* wait for image check */
+
+    serial = 0;
+    readn (c->sk, &serial, sizeof (serial));
+    if (serial != closure->id)
+	exit (-1);
+}
+
+static cairo_surface_t *
+_surface_create (void *closure,
+		 cairo_content_t content,
+		 double width, double height)
+{
+    struct client *c = closure;
+    cairo_surface_t *surface;
+
+    surface = cairo_surface_create_similar (c->surface,
+					    content, width, height);
+    if (cairo_surface_get_type (surface) != CAIRO_SURFACE_TYPE_IMAGE) {
+	struct surface_tag *tag;
+
+	tag = xmalloc (sizeof (*tag));
+	tag->width = width;
+	tag->height = height;
+	if (cairo_surface_set_user_data (surface, &surface_tag, tag, free))
+	    exit (-1);
+    }
+
+    return surface;
+}
+
+static cairo_t *
+_context_create (void *closure, cairo_surface_t *surface)
+{
+    struct client *c = closure;
+    struct context_closure *l;
+    cairo_bool_t foreign = FALSE;
+
+    l = xmalloc (sizeof (*l));
+    l->next = c->contexts;
+    l->surface = surface;
+    l->original = cairo_surface_reference (surface);
+    l->id = ++c->context_id;
+    if (l->id == 0)
+	l->id = ++c->context_id;
+    c->contexts = l;
+
+    /* record everything, including writes to images */
+    if (c->target == NULL) {
+	if (cairo_surface_get_type (surface) != CAIRO_SURFACE_TYPE_META) {
+	    cairo_format_t format;
+	    int width, height;
+
+	    get_surface_size (surface, &width, &height, &format);
+	    l->surface = cairo_surface_create_similar (c->surface,
+						       cairo_surface_get_content (surface),
+						       width, height);
+	    foreign = TRUE;
+	}
+    }
+
+    l->context = cairo_create (l->surface);
+    if (foreign) {
+	cairo_set_source_surface (l->context, surface, 0, 0);
+	cairo_paint (l->context);
+    }
+
+    return l->context;
+}
+
+static void
+_context_destroy (void *closure, void *ptr)
+{
+    struct client *c = closure;
+    struct context_closure *l, **prev = &c->contexts;
+
+    while ((l = *prev) != NULL) {
+	if (l->context == ptr) {
+	    if (cairo_surface_status (l->surface) == CAIRO_STATUS_SUCCESS) {
+		if (c->target == NULL)
+		    send_meta (c, l);
+		else
+		    send_surface (c, l);
+            } else {
+		exit (-1);
+	    }
+
+            cairo_surface_destroy (l->original);
+            *prev = l->next;
+            free (l);
+            return;
+        }
+        prev = &l->next;
+    }
+}
+
+static void *
+recorder (void *arg)
+{
+    struct client client;
+    const cairo_script_interpreter_hooks_t hooks = {
+	.closure = &client,
+	.surface_create = _surface_create,
+	.context_create = _context_create,
+	.context_destroy = _context_destroy,
+    };
+    char *buf;
+    int buf_size;
+    int len = 0, ret;
+    struct pollfd pfd;
+
+    client.target = NULL;
+    client.sk = client_socket ("/tmp/cairo-sphinx");
+    if (client.sk < 0)
+	return NULL;
+
+    buf_size = 65536;
+    buf = xmalloc (buf_size);
+
+    len = sprintf (buf, "client-command target=meta name=.recorder\n");
+    if (! writen (client.sk, buf, len))
+	return NULL;
+
+    /* drain the shm_path */
+    len = readline (client.sk, buf, buf_size);
+
+    pfd.fd = client_socket ("/tmp/cairo-sphinx");
+    if (pfd.fd < 0)
+	return NULL;
+
+    len = sprintf (buf, "client-trace name=.recorder\n");
+    if (! writen (pfd.fd, buf, len))
+	return NULL;
+
+    client.surface = cairo_meta_surface_create (CAIRO_CONTENT_COLOR_ALPHA,
+						NULL);
+
+    client.context_id = 0;
+    client.csi = cairo_script_interpreter_create ();
+    cairo_script_interpreter_install_hooks (client.csi, &hooks);
+
+    nonblocking (pfd.fd);
+    pfd.events = POLLIN;
+    len = 0;
+    while (poll (&pfd, 1, -1) > 0) {
+	while ((ret = read (pfd.fd, buf + len, buf_size - len)) > 0) {
+	    int end;
+
+	    if (ret == buf_size - len) {
+		buf_size *= 2;
+		buf = xrealloc (buf, buf_size);
+	    }
+	    len += ret;
+
+	    for (end = len; end > 0 && buf[--end] != '\n'; )
+		;
+	    if (end > 0) {
+		buf[end] = '\0';
+		cairo_script_interpreter_feed_string (client.csi, buf, end);
+
+		len -= end + 1;
+		if (len)
+		    memmove (buf, buf + end + 1, len);
+	    }
+	}
+	if (ret == 0)
+	    break;
+	if (! (errno == EAGAIN || errno == EINTR))
+	    break;
+    }
+
+    cairo_script_interpreter_finish (client.csi);
+    cairo_script_interpreter_destroy (client.csi);
+
+    cairo_surface_destroy (client.surface);
+    return NULL;
+}
+
+static int
+do_server (const char *path)
+{
+    pthread_t thread;
+    struct clients clients;
+    char line[4096];
+    struct pollfd *pfd;
+    int num_pfd, size_pfd;
+    int n, cnt, ret = 1;
+    int sk, source = -1;
+    int waiter = -1, waiter_count = 0;
+    int len;
+
+    signal (SIGPIPE, SIG_IGN);
+
+    if (clients_init (&clients) < 0) {
+	fprintf (stderr, "Failed to initialise clients structure\n");
+	return -1;
+    }
+
+    sk = server_socket (path);
+    if (sk < 0) {
+	fprintf (stderr, "Failed to create server socket\n");
+	return 1;
+    }
+
+    if (daemonize () < 0)
+	return 1;
+
+    if (pthread_create (&thread, NULL, recorder, NULL) < 0) {
+	fprintf (stderr, "Failed to create spawn recording thread\n");
+	return 1;
+    }
+
+    size_pfd = 4;
+    pfd = xmalloc (sizeof (*pfd) * size_pfd);
+    pfd[0].fd = sk;
+    pfd[0].events = POLLIN;
+    num_pfd = 1;
+
+    while ((cnt = poll (pfd, num_pfd, -1)) > 0) {
+	int have_source;
+
+	if (pfd[0].revents) {
+	    while ((sk = accept (pfd[0].fd, NULL, NULL)) != -1) {
+		len = readline (sk, line, sizeof (line));
+		if (strcmp (line, "source") == 0) {
+
+		    if (source != -1)
+			exit (1);
+
+		    source = sk;
+		    if (nonblocking (sk) < 0) {
+			close (sk);
+			continue;
+		    }
+		} else if (strncmp (line, "client-command", 14) == 0) {
+		    if (source == -1)
+			clients_add_command (&clients, sk, line);
+		} else if (strncmp (line, "client-trace", 12) == 0) {
+		    if (source == -1) {
+			clients_add_trace (&clients, sk, line);
+			if (nonblocking (sk) < 0) {
+			    close (sk);
+			    continue;
+			}
+
+			if (clients.count == waiter_count) {
+			    for (n = 1; n < num_pfd; n++) {
+				if (pfd[n].fd == waiter) {
+				    pfd[n].fd = -1;
+				    break;
+				}
+			    }
+			    close (waiter);
+			    waiter_count = -1;
+			}
+		    }
+		} else if (strncmp (line, "wait", 4) == 0) {
+		    int count = atoi (line + 5) + 1;
+		    if (clients.count == count) {
+			close (sk);
+			continue;
+		    } else {
+			waiter = sk;
+			waiter_count = count;
+		    }
+		}
+
+		if (num_pfd == size_pfd) {
+		    size_pfd *= 2;
+		    pfd = xrealloc (pfd, sizeof (*pfd) * size_pfd);
+		}
+
+		pfd[num_pfd].fd = sk;
+		pfd[num_pfd].events = POLLIN;
+		pfd[num_pfd].revents = 0;
+		num_pfd++;
+	    }
+	    cnt--;
+	}
+
+	have_source = 0;
+	for (n = 1; cnt && n < num_pfd; n++) {
+	    if (! pfd[n].revents)
+		continue;
+	    cnt--;
+
+	    if (pfd[n].fd == -1)
+		continue;
+
+	    if (source == pfd[n].fd) {
+		have_source = n;
+	    } else {
+		len = readline (pfd[n].fd, line, sizeof (line));
+		if (len < 0) {
+		    clients_remove (&clients, pfd[n].fd);
+		    close (pfd[n].fd);
+		    pfd[n].fd = -1;
+		    continue;
+		}
+
+		 if (strncmp (line, ".image", 6) == 0) {
+		    if (! clients_image (&clients, pfd[n].fd, line + 7)) {
+			clients_remove (&clients, pfd[n].fd);
+			close (pfd[n].fd);
+			pfd[n].fd = -1;
+			continue;
+		    }
+		} else if (strncmp (line, ".complete", 9) == 0) {
+		    clients_complete (&clients, pfd[n].fd);
+		} else if (strncmp (line, ".meta", 5) == 0) {
+		    clients_meta (&clients, pfd[n].fd, line + 6);
+		} else {
+		    printf ("do_command (%s)\n", line);
+		}
+	    }
+	}
+
+	if (have_source) {
+	    do {
+		len = read (source, line, sizeof (line));
+		if (len > 0) {
+		    clients_send_trace (&clients, line, len);
+		} else if (len == 0) {
+		    close (source);
+		    pfd[have_source].fd = source = -1;
+		    goto done;
+		} else
+		    break;
+	    } while (1);
+	}
+
+	for (n = cnt = 1; n < num_pfd; n++) {
+	    if (pfd[n].fd != -1) {
+		if (cnt != n)
+		    pfd[cnt] = pfd[n];
+		cnt++;
+	    }
+	}
+	num_pfd = cnt;
+    }
+
+done:
+    ret = 0;
+    for (n = 0; n < num_pfd; n++) {
+	if (pfd[n].fd != -1)
+	    close (pfd[n].fd);
+    }
+    free (pfd);
+    clients_fini (&clients);
+
+    return ret;
+}
+
+static void *
+client_shm (const char *shm_path)
+{
+    void *base;
+    int fd;
+
+    fd = shm_open (shm_path, O_RDWR, 0);
+    if (fd == -1)
+	return MAP_FAILED;
+
+    base = mmap (NULL, DATA_SIZE,
+		 PROT_READ | PROT_WRITE,
+		 MAP_SHARED | MAP_NORESERVE,
+		 fd, 0);
+    close (fd);
+
+    return base;
+}
+
+static int
+client_socket (const char *socket_path)
+{
+    struct sockaddr_un addr;
+    int sk;
+
+    sk = socket (PF_UNIX, SOCK_STREAM, 0);
+    if (sk == -1)
+	return -1;
+
+    memset (&addr, 0, sizeof (addr));
+    addr.sun_family = AF_UNIX;
+    strcpy (addr.sun_path, socket_path);
+
+    if (connect (sk, (struct sockaddr *) &addr, sizeof (addr)) == -1)
+	return -1;
+
+    return sk;
+}
+
+static int
+do_client (int fd,
+	   const char *target,
+	   const char *name,
+	   const char *reference,
+	   cairo_content_t content)
+{
+    struct client client;
+    const cairo_script_interpreter_hooks_t hooks = {
+	.closure = &client,
+	.surface_create = _surface_create,
+	.context_create = _context_create,
+	.context_destroy = _context_destroy,
+    };
+    void *closure;
+    char *buf;
+    int buf_size;
+    int len = 0, ret;
+    struct pollfd pfd;
+
+    client.sk = fd;
+    client.target = cairo_boilerplate_get_target_by_name (target, content);
+    client.context_id = 0;
+
+    client.surface = client.target->create_surface (NULL, content, 1, 1, 1, 1,
+						    CAIRO_BOILERPLATE_MODE_TEST,
+						    0, &closure);
+    if (client.surface == NULL) {
+	fprintf (stderr, "Failed to create target surface: %s.\n",
+		 client.target->name);
+	return 1;
+    }
+
+    buf_size = 65536;
+    buf = xmalloc (buf_size);
+
+    if (reference != NULL) {
+	len = sprintf (buf,
+		       "client-command name=%s target=%s reference=%s\n",
+		       name, target, reference);
+    } else {
+	len = sprintf (buf,
+		       "client-command name=%s target=%s\n",
+		       name, target);
+    }
+    if (! writen (fd, buf, len))
+	return 1;
+
+    len = readline (fd, buf, buf_size);
+    client.base = client_shm (buf);
+    if (client.base == MAP_FAILED) {
+	fprintf (stderr, "Failed to map shared memory segment '%s'.\n", buf);
+	return 1;
+    }
+
+    if (daemonize () < 0)
+	return 1;
+
+    pfd.fd = client_socket ("/tmp/cairo-sphinx");
+    if (pfd.fd < 0)
+	return 1;
+
+    len = sprintf (buf, "client-trace name=%s\n", name);
+    if (! writen (pfd.fd, buf, len))
+	return 1;
+
+    client.csi = cairo_script_interpreter_create ();
+    cairo_script_interpreter_install_hooks (client.csi, &hooks);
+
+    nonblocking (pfd.fd);
+    pfd.events = POLLIN;
+    len = 0;
+    while (poll (&pfd, 1, -1) > 0) {
+	while ((ret = read (pfd.fd, buf + len, buf_size - len)) > 0) {
+	    int end;
+
+	    if (ret == buf_size - len) {
+		buf_size *= 2;
+		buf = xrealloc (buf, buf_size);
+	    }
+	    len += ret;
+
+	    for (end = len; end > 0 && buf[--end] != '\n'; )
+		;
+	    if (end > 0) {
+		buf[end] = '\0';
+		cairo_script_interpreter_feed_string (client.csi, buf, end);
+
+		len -= end + 1;
+		if (len)
+		    memmove (buf, buf + end + 1, len);
+	    }
+	}
+	if (ret == 0)
+	    break;
+	if (! (errno == EAGAIN || errno == EINTR))
+	    break;
+    }
+
+    cairo_script_interpreter_finish (client.csi);
+    cairo_script_interpreter_destroy (client.csi);
+
+    cairo_surface_destroy (client.surface);
+    close (fd);
+
+    return 0;
+}
+
+static int
+do_exec (int fd, char **argv)
+{
+    char buf[4096];
+
+    if (*argv == NULL)
+	return 0;
+
+    snprintf (buf, sizeof (buf), "%s/cairo-trace.so", LIBDIR);
+    setenv ("LD_PRELOAD", buf, 1);
+
+    snprintf (buf, sizeof (buf), "0");
+    setenv ("CAIRO_TRACE_LINE_INFO", buf, 1);
+
+    snprintf (buf, sizeof (buf), "%d", fd);
+    setenv ("CAIRO_TRACE_FD", buf, 1);
+    putenv (buf);
+
+    return execvp (argv[0], argv);
+}
+
+static int
+do_wait (int fd)
+{
+    char buf;
+    int ret = read (fd, &buf, 1);
+    return ret != 0;
+}
+
+int
+main (int argc, char **argv)
+{
+    char buf[4096];
+    int len;
+    int fd;
+
+    if (argc == 1)
+	return do_server ("/tmp/cairo-sphinx");
+
+    fd = client_socket ("/tmp/cairo-sphinx");
+    if (fd < 0)
+	return 1;
+
+    if (strcmp (argv[1], "client") == 0) {
+	return do_client (fd, argv[2], argv[3], argv[4],
+			  CAIRO_CONTENT_COLOR_ALPHA);
+    }
+
+    if (strcmp (argv[1], "wait") == 0) {
+	len = snprintf (buf, sizeof (buf), "wait %s\n", argv[2]);
+	if (! writen (fd, buf, len))
+	    return 1;
+
+	return do_wait (fd);
+    }
+
+    if (strcmp (argv[1], "exec") == 0) {
+	len = snprintf (buf, sizeof (buf), "source\n");
+	if (! writen (fd, buf, len))
+	    return 1;
+
+	return do_exec (fd, argv+2);
+    }
+
+    if (strcmp (argv[1], "replay") == 0) {
+	len = snprintf (buf, sizeof (buf), "replay %s\n", argv[2]);
+	return ! writen (fd, buf, len);
+    }
+
+    return 0;
+}