[libsigrokdecode.git] / controller.c

/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
 * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
 *
 * 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/>.
 */

#include "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
#include "sigrokdecode-internal.h"
#include "config.h"
#include <glib.h>
#include <inttypes.h>
#include <stdlib.h>


/* List of decoder instances. */
static GSList *di_list = NULL;

/* List of frontend callbacks to receive PD output. */
static GSList *callbacks = NULL;

/* lives in decoder.c */
extern GSList *pd_list;

/* lives in module_sigrokdecode.c */
extern PyMODINIT_FUNC PyInit_sigrokdecode(void);

/* lives in type_logic.c */
extern PyTypeObject srd_logic_type;


/**
 * Initialize libsigrokdecode.
 *
 * This initializes the Python interpreter, and creates and initializes
 * a "sigrok" Python module with a single put() method.
 *
 * Then, it searches for sigrok protocol decoder files (*.py) in the
 * "decoders" subdirectory of the the sigrok installation directory.
 * All decoders that are found are loaded into memory and added to an
 * internal list of decoders, which can be queried via srd_list_decoders().
 *
 * The caller is responsible for calling the clean-up function srd_exit(),
 * which will properly shut down libsigrokdecode and free its allocated memory.
 *
 * Multiple calls to srd_init(), without calling srd_exit() in between,
 * are not allowed.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *         Upon Python errors, return SRD_ERR_PYTHON. If the sigrok decoders
 *         directory cannot be accessed, return SRD_ERR_DECODERS_DIR.
 *         If not enough memory could be allocated, return SRD_ERR_MALLOC.
 */
int srd_init(void)
{
        int ret;

        srd_dbg("Initializing libsigrokdecode.");

        /* Add our own module to the list of built-in modules. */
        PyImport_AppendInittab("sigrokdecode", PyInit_sigrokdecode);

        /* Initialize the python interpreter. */
        Py_Initialize();

        if ((ret = set_modulepath()) != SRD_OK) {
                Py_Finalize();
                return ret;
        }

        if ((ret = srd_load_all_decoders()) != SRD_OK) {
                Py_Finalize();
                return ret;
        }

        return SRD_OK;
}


/**
 * Shutdown libsigrokdecode.
 *
 * This frees all the memory allocated for protocol decoders and shuts down
 * the Python interpreter.
 *
 * This function should only be called if there was a (successful!) invocation
 * of srd_init() before. Calling this function multiple times in a row, without
 * any successful srd_init() calls in between, is not allowed.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 */
int srd_exit(void)
{

        srd_dbg("Exiting libsigrokdecode.");

        srd_unload_all_decoders();
        g_slist_free(pd_list);

        /* Py_Finalize() returns void, any finalization errors are ignored. */
        Py_Finalize();

        return SRD_OK;
}


/**
 * Add an additional search directory for the protocol decoders.
 *
 * The specified directory is prepended (not appended!) to Python's sys.path,
 * in order to search for sigrok protocol decoders in the specified
 * directories first, and in the generic Python module directories (and in
 * the current working directory) last. This avoids conflicts if there are
 * Python modules which have the same name as a sigrok protocol decoder in
 * sys.path or in the current working directory.
 *
 * TODO: add path from env var SIGROKDECODE_PATH, config etc
 * TODO: Should take directoryname/path as input.
 *
 * @return TODO.
 */
int set_modulepath(void)
{
        int ret;
        gchar *path, *s;

#ifdef _WIN32
        gchar **splitted;

        /*
         * On Windows/MinGW, Python's sys.path needs entries of the form
         * 'C:\\foo\\bar' instead of '/foo/bar'.
         */

        splitted = g_strsplit(DECODERS_DIR, "/", 0);
        path = g_build_pathv("\\\\", splitted);
        g_strfreev(splitted);
#else
        path = g_strdup(DECODERS_DIR);
#endif

        /* TODO: Sanity check on 'path' (length, escape special chars, ...). */
        s = g_strdup_printf("import sys; sys.path.insert(0, r'%s')", path);

        ret = PyRun_SimpleString(s);

        g_free(path);
        g_free(s);

        return ret;
}


/**
 * Set options in a decoder instance.
 *
 * @param di Decoder instance.
 * @param options A GHashTable of options to set.
 *
 * Handled options are removed from the hash.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 */
int srd_instance_set_options(struct srd_decoder_instance *di,
                GHashTable *options)
{
        PyObject *py_dec_options, *py_dec_optkeys, *py_di_options, *py_optval;
        PyObject *py_optlist, *py_classval;
        Py_UNICODE *py_ustr;
        unsigned long long int val_ull;
        int num_optkeys, ret, size, i;
        char *key, *value;

        if(!PyObject_HasAttrString(di->decoder->py_dec, "options")) {
                /* Decoder has no options. */
                if (g_hash_table_size(options) == 0) {
                        /* No options provided. */
                        return SRD_OK;
                } else {
                        srd_err("Protocol decoder has no options.");
                        return SRD_ERR_ARG;
                }
                return SRD_OK;
        }

        ret = SRD_ERR_PYTHON;
        key = NULL;
        py_dec_options = py_dec_optkeys = py_di_options = py_optval = NULL;
        py_optlist = py_classval = NULL;
        py_dec_options = PyObject_GetAttrString(di->decoder->py_dec, "options");

        /* All of these are synthesized objects, so they're good. */
        py_dec_optkeys = PyDict_Keys(py_dec_options);
        num_optkeys = PyList_Size(py_dec_optkeys);
        if (!(py_di_options = PyObject_GetAttrString(di->py_instance, "options")))
                goto err_out;
        for (i = 0; i < num_optkeys; i++) {
                /* Get the default class value for this option. */
                py_str_as_str(PyList_GetItem(py_dec_optkeys, i), &key);
                if (!(py_optlist = PyDict_GetItemString(py_dec_options, key)))
                        goto err_out;
                if (!(py_classval = PyList_GetItem(py_optlist, 1)))
                        goto err_out;
                if (!PyUnicode_Check(py_classval) && !PyLong_Check(py_classval)) {
                        srd_err("Options of type %s are not yet supported.", Py_TYPE(py_classval)->tp_name);
                        goto err_out;
                }

                if ((value = g_hash_table_lookup(options, key))) {
                        /* An override for this option was provided. */
                        if (PyUnicode_Check(py_classval)) {
                                if (!(py_optval = PyUnicode_FromString(value))) {
                                        /* Some UTF-8 encoding error. */
                                        PyErr_Clear();
                                        goto err_out;
                                }
                        } else if (PyLong_Check(py_classval)) {
                                if (!(py_optval = PyLong_FromString(value, NULL, 0))) {
                                        /* ValueError Exception */
                                        PyErr_Clear();
                                        srd_err("Option %s has invalid value %s: expected integer.",
                                                        key, value);
                                        goto err_out;
                                }
                        }
                        g_hash_table_remove(options, key);
                } else {
                        /* Use the class default for this option. */
                        if (PyUnicode_Check(py_classval)) {
                                /* Make a brand new copy of the string. */
                                py_ustr = PyUnicode_AS_UNICODE(py_classval);
                                size = PyUnicode_GET_SIZE(py_classval);
                                py_optval = PyUnicode_FromUnicode(py_ustr, size);
                        } else if (PyLong_Check(py_classval)) {
                                /* Make a brand new copy of the integer. */
                                val_ull = PyLong_AsUnsignedLongLong(py_classval);
                                if (val_ull == (unsigned long long)-1) {
                                        /* OverFlowError exception */
                                        PyErr_Clear();
                                        srd_err("Invalid integer value for %s: expected integer.", key);
                                        goto err_out;
                                }
                                if (!(py_optval = PyLong_FromUnsignedLongLong(val_ull)))
                                        goto err_out;
                        }
                }

                /* If we got here, py_optval holds a known good new reference
                 * to the instance option to set.
                 */
                if (PyDict_SetItemString(py_di_options, key, py_optval) == -1)
                        goto err_out;
        }

        ret = SRD_OK;

err_out:
        Py_XDECREF(py_optlist);
        Py_XDECREF(py_di_options);
        Py_XDECREF(py_dec_optkeys);
        Py_XDECREF(py_dec_options);
        if (key)
                g_free(key);
        if (PyErr_Occurred())
                catch_exception("Stray exception in srd_instance_set_options().");

        return ret;
}

/* Helper GComparefunc for g_slist_find_custom() in srd_instance_set_probes() */
static gint compare_probe_id(struct srd_probe *a, char *probe_id)
{

        return strcmp(a->id, probe_id);
}

/**
 * Set probes in a decoder instance.
 *
 * @param di Decoder instance.
 * @param probes A GHashTable of probes to set. Key is probe name, value is
 * the probe number. Samples passed to this instance will be arranged in this
 * order.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 */
int srd_instance_set_probes(struct srd_decoder_instance *di,
                GHashTable *new_probes)
{
        GList *l;
        GSList *sl;
        struct srd_probe *p;
        int *new_probemap, new_probenum;
        char *probe_id, *probenum_str;

        srd_dbg("set probes called for instance %s with list of %d probes",
                        di->instance_id, g_hash_table_size(new_probes));

        if (g_hash_table_size(new_probes) == 0)
                /* No probes provided. */
                return SRD_OK;

        if(di->dec_num_probes == 0) {
                /* Decoder has no probes. */
                srd_err("Protocol decoder %s has no probes to define.",
                                di->decoder->name);
                return SRD_ERR_ARG;
        }

        new_probemap = NULL;

        if (!(new_probemap = g_try_malloc(sizeof(int) * di->dec_num_probes))) {
                srd_err("Failed to malloc new probe map.");
                return SRD_ERR_MALLOC;
        }

        for (l = g_hash_table_get_keys(new_probes); l; l = l->next) {
                probe_id = l->data;
                probenum_str = g_hash_table_lookup(new_probes, probe_id);
                if (!probenum_str) {
                        /* Probe name was specified without a value. */
                        srd_err("No probe number was specified for %s.", probe_id);
                        g_free(new_probemap);
                        return SRD_ERR_ARG;
                }
                new_probenum = strtol(probenum_str, NULL, 10);
                if (!(sl = g_slist_find_custom(di->decoder->probes, probe_id,
                                (GCompareFunc)compare_probe_id))) {
                        /* Fall back on optional probes. */
                        if (!(sl = g_slist_find_custom(di->decoder->extra_probes,
                                        probe_id, (GCompareFunc)compare_probe_id))) {
                                srd_err("Protocol decoder %s has no probe '%s'.",
                                                di->decoder->name, probe_id);
                                g_free(new_probemap);
                                return SRD_ERR_ARG;
                        }
                }
                p = sl->data;
                new_probemap[p->order] = new_probenum;
                srd_dbg("setting probe mapping for %d = probe %d", p->order, new_probenum);
        }
        g_free(di->dec_probemap);
        di->dec_probemap = new_probemap;

        return SRD_OK;
}

/**
 * Create a new protocol decoder instance.
 *
 * @param id Decoder 'id' field.
 * @param options GHashtable of options which override the defaults set in
 *          the decoder class.
 * @return Pointer to a newly allocated struct srd_decoder_instance, or
 *              NULL in case of failure.
 */
struct srd_decoder_instance *srd_instance_new(const char *decoder_id,
                GHashTable *options)
{
        struct srd_decoder *dec;
        struct srd_decoder_instance *di;
        int i;
        char *instance_id;

        srd_dbg("Creating new %s instance.", decoder_id);

        if (!(dec = srd_get_decoder_by_id(decoder_id))) {
                srd_err("Protocol decoder %s not found.", decoder_id);
                return NULL;
        }

        if (!(di = g_try_malloc0(sizeof(*di)))) {
                srd_err("Failed to malloc instance.");
                return NULL;
        }

        instance_id = g_hash_table_lookup(options, "id");
        di->decoder = dec;
        di->instance_id = g_strdup(instance_id ? instance_id : decoder_id);
        g_hash_table_remove(options, "id");

        /* Prepare a default probe map, where samples come in the
         * order in which the decoder class defined them.
         */
        di->dec_num_probes = g_slist_length(di->decoder->probes) +
                        g_slist_length(di->decoder->extra_probes);
        if (di->dec_num_probes) {
                if (!(di->dec_probemap = g_try_malloc(sizeof(int) * di->dec_num_probes))) {
                        srd_err("Failed to malloc probe map.");
                        g_free(di);
                        return NULL;
                }
                for (i = 0; i < di->dec_num_probes; i++)
                        di->dec_probemap[i] = i;
        }

        /* Create a new instance of this decoder class. */
        if (!(di->py_instance = PyObject_CallObject(dec->py_dec, NULL))) {
                if (PyErr_Occurred())
                        catch_exception("failed to create %s instance: ", decoder_id);
                g_free(di->dec_probemap);
                g_free(di);
                return NULL;
        }

        if (srd_instance_set_options(di, options) != SRD_OK) {
                g_free(di->dec_probemap);
                g_free(di);
                return NULL;
        }

        /* Instance takes input from a frontend by default. */
        di_list = g_slist_append(di_list, di);

        return di;
}

int srd_instance_stack(struct srd_decoder_instance *di_from,
                struct srd_decoder_instance *di_to)
{

        if (!di_from || !di_to) {
                srd_err("Invalid from/to instance pair.");
                return SRD_ERR_ARG;
        }

        if (g_slist_find(di_list, di_to)) {
                /* Remove from the unstacked list. */
                di_list = g_slist_remove(di_list, di_to);
        }

        /* Stack on top of source di. */
        di_from->next_di = g_slist_append(di_from->next_di, di_to);

        return SRD_OK;
}

/**
 * Finds a decoder instance by its instance id, but only in the bottom
 * level of instances -- instances already stacked on top of another one
 * will not be found.
 *
 * @param instance_id The instance id to be found.
 *
 * @return Pointer to struct srd_decoder_instance, or NULL if not found.
 */
struct srd_decoder_instance *srd_instance_find_by_id(char *instance_id)
{
        GSList *l;
        struct srd_decoder_instance *tmp, *di;

        di = NULL;
        for (l = di_list; l; l = l->next) {
                tmp = l->data;
                if (!strcmp(tmp->instance_id, instance_id)) {
                        di = tmp;
                        break;
                }
        }

        return di;
}

/**
 * Finds a decoder instance by its python object, i.e. that instance's
 * instantiation of the sigrokdecode.Decoder class. This will recurse
 * to find the instance anywhere in the stack tree.
 *
 * @param stack Pointer to a GSList of struct srd_decoder_instance,
 *              indicating the stack to search. To start searching at the bottom
 *              level of decoder instances, pass NULL.
 * @param obj The python class instantiation.
 *
 * @return Pointer to struct srd_decoder_instance, or NULL if not found.
 */
struct srd_decoder_instance *srd_instance_find_by_obj(GSList *stack,
                PyObject *obj)
{
        GSList *l;
        struct srd_decoder_instance *tmp, *di;

        di = NULL;
        for (l = stack ? stack : di_list; di == NULL && l != NULL; l = l->next) {
                tmp = l->data;
                if (tmp->py_instance == obj)
                        di = tmp;
                else if (tmp->next_di)
                        di = srd_instance_find_by_obj(tmp->next_di, obj);
        }

        return di;
}

int srd_instance_start(struct srd_decoder_instance *di, PyObject *args)
{
        PyObject *py_name, *py_res;
        GSList *l;
        struct srd_decoder_instance *next_di;

        srd_dbg("Calling start() method on protocol decoder instance %s.",
                di->instance_id);

        if (!(py_name = PyUnicode_FromString("start"))) {
                srd_err("Unable to build python object for 'start'.");
                catch_exception("Protocol decoder instance %s: ", di->instance_id);
                return SRD_ERR_PYTHON;
        }

        if (!(py_res = PyObject_CallMethodObjArgs(di->py_instance,
                        py_name, args, NULL))) {
                catch_exception("Protocol decoder instance %s: ", di->instance_id);
                return SRD_ERR_PYTHON;
        }

        Py_DecRef(py_res);
        Py_DecRef(py_name);

        /* Start all the PDs stacked on top of this one. Pass along the
         * metadata all the way from the bottom PD, even though it's only
         * applicable to logic data for now.
         */
        for (l = di->next_di; l; l = l->next) {
                next_di = l->data;
                srd_instance_start(next_di, args);
        }

        return SRD_OK;
}

/**
 * Run the specified decoder function.
 *
 * @param start_samplenum The starting sample number for the buffer's sample
 *                        set, relative to the start of capture.
 * @param di The decoder instance to call. Must not be NULL.
 * @param inbuf The buffer to decode. Must not be NULL.
 * @param inbuflen Length of the buffer. Must be > 0.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 */
int srd_instance_decode(uint64_t start_samplenum,
        struct srd_decoder_instance *di, uint8_t *inbuf, uint64_t inbuflen)
{
        PyObject *py_res;
        srd_logic *logic;
        uint64_t end_samplenum;

        srd_dbg("Calling decode() on instance %s with %d bytes starting "
                "at sample %d.", di->instance_id, inbuflen, start_samplenum);

        /* Return an error upon unusable input. */
        if (!di) {
                srd_dbg("empty decoder instance");
                return SRD_ERR_ARG;
        }
        if (!inbuf) {
                srd_dbg("NULL buffer pointer");
                return SRD_ERR_ARG;
        }
        if (inbuflen == 0) {
                srd_dbg("empty buffer");
                return SRD_ERR_ARG;
        }

        /* Create new srd_logic object. Each iteration around the PD's loop
         * will fill one sample into this object.
         */
        logic = PyObject_New(srd_logic, &srd_logic_type);
        Py_INCREF(logic);
        logic->di = di;
        logic->start_samplenum = start_samplenum;
        logic->itercnt = 0;
        logic->inbuf = inbuf;
        logic->inbuflen = inbuflen;
        logic->sample = PyList_New(2);
        Py_INCREF(logic->sample);

        Py_IncRef(di->py_instance);
        end_samplenum = start_samplenum + inbuflen / di->data_unitsize;
        if (!(py_res = PyObject_CallMethod(di->py_instance, "decode",
                        "KKO", logic->start_samplenum, end_samplenum, logic))) {
                catch_exception("Protocol decoder instance %s: ", di->instance_id);
                return SRD_ERR_PYTHON; /* TODO: More specific error? */
        }
        Py_DecRef(py_res);

        return SRD_OK;
}


int srd_session_start(int num_probes, int unitsize, uint64_t samplerate)
{
        PyObject *args;
        GSList *d;
        struct srd_decoder_instance *di;
        int ret;

        srd_dbg("Calling start() on all instances with %d probes, "
                "unitsize %d samplerate %d.", num_probes, unitsize, samplerate);

        /* Currently only one item of metadata is passed along to decoders,
         * samplerate. This can be extended as needed.
         */
        if (!(args = Py_BuildValue("{s:l}", "samplerate", (long)samplerate))) {
                srd_err("Unable to build python object for metadata.");
                return SRD_ERR_PYTHON;
        }

        /* Run the start() method on all decoders receiving frontend data. */
        for (d = di_list; d; d = d->next) {
                di = d->data;
                di->data_num_probes = num_probes;
                di->data_unitsize = unitsize;
                di->data_samplerate = samplerate;
                if ((ret = srd_instance_start(di, args) != SRD_OK))
                        break;
        }

        Py_DecRef(args);

        return ret;
}

/* Feed logic samples to decoder session. */
int srd_session_feed(uint64_t start_samplenum, uint8_t *inbuf, uint64_t inbuflen)
{
        GSList *d;
        int ret;

        srd_dbg("Calling decode() on all instances with starting sample "
                "number %"PRIu64", %"PRIu64" bytes at 0x%p", start_samplenum,
                inbuflen, inbuf);

        for (d = di_list; d; d = d->next) {
                if ((ret = srd_instance_decode(start_samplenum, d->data, inbuf,
                                inbuflen)) != SRD_OK)
                        return ret;
        }

        return SRD_OK;
}


int srd_register_callback(int output_type, void *cb)
{
        struct srd_pd_callback *pd_cb;

        srd_dbg("Registering new callback for output type %d.", output_type);

        if (!(pd_cb = g_try_malloc(sizeof(struct srd_pd_callback))))
                return SRD_ERR_MALLOC;

        pd_cb->output_type = output_type;
        pd_cb->callback = cb;
        callbacks = g_slist_append(callbacks, pd_cb);

        return SRD_OK;
}

void *srd_find_callback(int output_type)
{
        GSList *l;
        struct srd_pd_callback *pd_cb;
        void *(cb);

        cb = NULL;
        for (l = callbacks; l; l = l->next) {
                pd_cb = l->data;
                if (pd_cb->output_type == output_type) {
                        cb = pd_cb->callback;
                        break;
                }
        }

        return cb;
}


/* This is the backend function to python sigrokdecode.add() call. */
int pd_add(struct srd_decoder_instance *di, int output_type, char *proto_id)
{
        struct srd_pd_output *pdo;

        srd_dbg("Instance %s creating new output type %d for %s.",
                di->instance_id, output_type, proto_id);

        if (!(pdo = g_try_malloc(sizeof(struct srd_pd_output))))
                return -1;

        /* pdo_id is just a simple index, nothing is deleted from this list anyway. */
        pdo->pdo_id = g_slist_length(di->pd_output);
        pdo->output_type = output_type;
        pdo->di = di;
        pdo->proto_id = g_strdup(proto_id);
        di->pd_output = g_slist_append(di->pd_output, pdo);

        return pdo->pdo_id;
}