/*
- * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2014 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
struct filter_node {
/** The number in the array of available filters. */
unsigned filter_num;
- /** The filter chain this filter node belongs to. */
- struct filter_chain *fc;
/**
* Each filter may store any filter-specific information about the particular
* instance of the filter here.
*/
void *private_data;
- /** The output buffer. */
- char *buf;
- /** The size of the output buffer. */
- size_t bufsize;
- /** The number of bytes currently loaded in \a buf. */
- size_t loaded;
/** The list of registered callbacks. */
struct list_head callbacks;
/** A pointer to the configuration of this instance. */
void *conf;
-};
-
-/** Describes one running instance of a chain of filters */
-struct filter_chain {
- /** The length of the filter chain. */
- unsigned int num_filters;
- /**
- * The number of channels of the current stream.
- *
- * Set by the decoding filter.
- */
- unsigned int channels;
- /**
- * Current sample rate in Hz.
- *
- * Set by the decoding filter.
- */
- unsigned int samplerate;
- /** The list containing all filter nodes in this filter chain. */
- struct filter_node *filter_nodes;
- /**
- * The input buffer of the filter chain.
- *
- * This is set to point to the output buffer of the receiving application (the
- * buffer used to read from stdin for para_filter; the output buffer of the
- * current receiver for para_audiod).
- */
- char **inbufp;
- /**
- * The output buffer of the filter chain.
- *
- * Points to the output buffer of the last filter in the filter chain.
- */
- char **outbufp;
- /** Contains the number of bytes loaded in the input buffer. */
- size_t *in_loaded;
- /** Contains the number of bytes loaded in the output buffer. */
- size_t *out_loaded;
- /** Pointer to the error variable of the receiving application. */
- int *input_error;
- /** Pointer to the error variable of the writing application. */
- int *output_error;
- /** The task associated with the filter chain. */
+ /** The buffer tree node. */
+ struct btr_node *btrn;
+ /** The task corresponding to this filter node. */
struct task task;
+ /** The minimal input queue size, see \ref btr_node_status(). */
+ size_t min_iqs;
};
-#define FOR_EACH_FILTER_NODE(fn, fc, i) for (i = 0; i < (fc)->num_filters \
- && (fn = (fc)->filter_nodes + i); i++)
-
-
-/**
- * Used to manage grab clients.
- *
- * An application using paraslash's filter subsystem may register any number of
- * callbacks for each filter_node. It is possible to attach a filter callback
- * while the filter is running. This is used for stream grabbing in
- * para_audiod: Whenever a client sends the 'grab' command, para_audiod adds a
- * filter callback to the list of callbacks for the filter node specified in
- * the grab command.
- */
-struct filter_callback {
- /** All callbacks are organized in a doubly linked list. */
- struct list_head node;
- /**
- * The input callback.
- *
- * If not \p NULL, the filter subsystem calls this function whenever the filter
- * consumed some or all of its input buffer. A pointer to the buffer of consumed
- * data, its length and a pointer to the own \a filter_callback structure are passed
- * to \a input_cb. The input callback is expected to return a negative value on errors.
- */
- int (*input_cb)(char *buf, size_t len, struct filter_callback *fc);
- /**
- * The output callback.
- *
- * If not NULL, this is called whenever the filter produces output. A pointer
- * to the output data, its length and a pointer to the own \a filter_callback
- * structure are passed to \a output_cb. Like the input callback, the output
- * callback is expected to return a negative value on errors.
- */
- int (*output_cb)(char *buf, size_t len, struct filter_callback *fc);
- /**
- * The callback close function.
- *
- * This gets called whenever the input/output callback returned an error, or if
- * the filter chain is going to be destroyed, e.g. because the end of the
- * stream was encountered. It is assumed to succeed.
- */
- void (*close)(struct filter_callback *fc);
-};
-
-
/**
* The structure associated with a paraslash filter.
*
* of \a fn suitably. The open function is assumed to succeed.
*/
void (*open)(struct filter_node *fn);
- /**
- * Convert (filter) the given data.
- *
- * Pointer to the converting function of the filter. It should convert the
- * given input buffer \a inbuf which is of length \a len to the previously
- * reserved output buffer of \a fn. On success, it must return the number of
- * bytes it consumed from \a inbuf. On errors, a negative number indicating the
- * kind of the error must be returned.
- *
- * A zero return value just means that nothing was converted (probably because
- * the input buffer was too small). This is not interpreted as an error.
- */
- ssize_t (*convert)(char *inbuf, size_t len, struct filter_node *fn);
/**
* Close one instance of this filter.
*
* Free all resources of associated with \a fn that were previously allocated
- * by the open() function.
+ * by the open() function. It's OK to leave this alone if the filter does not
+ * need any cleanups.
*/
void (*close)(struct filter_node *fn);
/**
* argv. On failure, a negative paraslash error code must be returned.
*/
int (*parse_config)(int argc, char **argv, void **config);
+ /**
+ * Deallocate the memory for the configuration.
+ *
+ * This is called to free whatever ->parse_config() has allocated.
+ */
+ void (*free_config)(void *conf);
/** The help texts for this filter. */
struct ggo_help help;
+ /**
+ * Set scheduler timeout and add file descriptors to fd sets.
+ *
+ * This function is used to control the timeout value for select. It
+ * only allowed to decrease the current value. The second purpose of
+ * this function is to set file descriptors to be watched by the
+ * subsequent select call to the two fd sets.
+ */
+ void (*pre_select)(struct sched *s, struct task *t);
+ /**
+ * Convert (filter) the given data.
+ *
+ * Pointer to the converting function of the filter. On errors, the
+ * post_select function is supposed to return a negative error code.
+ */
+ int (*post_select)(struct sched *s, struct task *t);
+ /**
+ * Answer a buffer tree query.
+ *
+ * This optional function pointer is used for inter node communications
+ * of the buffer tree nodes. See \ref btr_command_handler for details.
+ */
+ btr_command_handler execute;
};
-void close_filters(struct filter_chain *fc);
void filter_init(void);
int check_filter_arg(char *filter_arg, void **conf);
-void filter_post_select(__a_unused struct sched *s, struct task *t);
-void print_filter_helps(int detailed);
+void print_filter_helps(unsigned flags);
+void generic_filter_pre_select(struct sched *s, struct task *t);
+int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
+ char **result);
static inline void write_int16_host_endian(char *buf, int val)
{
DECLARE_FILTER_INITS
+/** Iterate over the array of supported filters. */
#define FOR_EACH_SUPPORTED_FILTER(j) for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
/** The filter array, one structure for each supported filter. */