libqos/qgraph: format qgraph comments for sphinx documentation

Change documentation style and fix minor typos in tests/qtest/libqos/qgraph.h
to automatically generate sphinx documentation in docs/devel/qgraph.rst

The mechanism explanation that once was in qgraph.h is now moved to qgraph.rst

There is no functional change intended.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210308073240.6363-1-eesposit@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 115 insertions, 335 deletions

diff --git a/tests/qtest/libqos/qgraph.h b/tests/qtest/libqos/qgraph.h
index 07a32535f1..54672350c8 100644
--- a/tests/qtest/libqos/qgraph.h
+++ b/tests/qtest/libqos/qgraph.h
@@ -29,7 +29,6 @@
 typedef struct QOSGraphObject QOSGraphObject;
 typedef struct QOSGraphNode QOSGraphNode;
 typedef struct QOSGraphEdge QOSGraphEdge;
-typedef struct QOSGraphNodeOptions QOSGraphNodeOptions;
 typedef struct QOSGraphEdgeOptions QOSGraphEdgeOptions;
 typedef struct QOSGraphTestOptions QOSGraphTestOptions;
 
@@ -49,340 +48,94 @@ typedef void (*QOSStartFunct) (QOSGraphObject *object);
 typedef void *(*QOSBeforeTest) (GString *cmd_line, void *arg);
 
 /**
- * SECTION: qgraph.h
- * @title: Qtest Driver Framework
- * @short_description: interfaces to organize drivers and tests
- *                     as nodes in a graph
- *
- * This Qgraph API provides all basic functions to create a graph
- * and instantiate nodes representing machines, drivers and tests
- * representing their relations with CONSUMES, PRODUCES, and CONTAINS
- * edges.
- *
- * The idea is to have a framework where each test asks for a specific
- * driver, and the framework takes care of allocating the proper devices
- * required and passing the correct command line arguments to QEMU.
- *
- * A node can be of four types:
- * - QNODE_MACHINE:   for example "arm/raspi2"
- * - QNODE_DRIVER:    for example "generic-sdhci"
- * - QNODE_INTERFACE: for example "sdhci" (interface for all "-sdhci" drivers)
- *                     an interface is not explicitly created, it will be auto-
- *                     matically instantiated when a node consumes or produces
- *                     it.
- * - QNODE_TEST:      for example "sdhci-test", consumes an interface and tests
- *                    the functions provided
- *
- * Notes for the nodes:
- * - QNODE_MACHINE: each machine struct must have a QGuestAllocator and
- *                  implement get_driver to return the allocator passing
- *                  "memory". The function can also return NULL if the
- *                  allocator is not set.
- * - QNODE_DRIVER:  driver names must be unique, and machines and nodes
- *                  planned to be "consumed" by other nodes must match QEMU
- *                  drivers name, otherwise they won't be discovered
- *
- * An edge relation between two nodes (drivers or machines) X and Y can be:
- * - X CONSUMES Y: Y can be plugged into X
- * - X PRODUCES Y: X provides the interface Y
- * - X CONTAINS Y: Y is part of X component
- *
- * Basic framework steps are the following:
- * - All nodes and edges are created in their respective
- *   machine/driver/test files
- * - The framework starts QEMU and asks for a list of available devices
- *   and machines (note that only machines and "consumed" nodes are mapped
- *   1:1 with QEMU devices)
- * - The framework walks the graph starting from the available machines and
- *   performs a Depth First Search for tests
- * - Once a test is found, the path is walked again and all drivers are
- *   allocated accordingly and the final interface is passed to the test
- * - The test is executed
- * - Unused objects are cleaned and the path discovery is continued
- *
- * Depending on the QEMU binary used, only some drivers/machines will be
- * available and only test that are reached by them will be executed.
- *
- * <example>
- *   <title>Creating new driver an its interface</title>
- *   <programlisting>
- #include "qgraph.h"
-
- struct My_driver {
-     QOSGraphObject obj;
-     Node_produced prod;
-     Node_contained cont;
- }
-
- static void my_destructor(QOSGraphObject *obj)
- {
-    g_free(obj);
- }
-
- static void my_get_driver(void *object, const char *interface) {
-    My_driver *dev = object;
-    if (!g_strcmp0(interface, "my_interface")) {
-        return &dev->prod;
-    }
-    abort();
- }
-
- static void my_get_device(void *object, const char *device) {
-    My_driver *dev = object;
-    if (!g_strcmp0(device, "my_driver_contained")) {
-        return &dev->cont;
-    }
-    abort();
- }
-
- static void *my_driver_constructor(void *node_consumed,
-                                    QOSGraphObject *alloc)
- {
-    My_driver dev = g_new(My_driver, 1);
-    // get the node pointed by the produce edge
-    dev->obj.get_driver = my_get_driver;
-    // get the node pointed by the contains
-    dev->obj.get_device = my_get_device;
-    // free the object
-    dev->obj.destructor = my_destructor;
-    do_something_with_node_consumed(node_consumed);
-    // set all fields of contained device
-    init_contained_device(&dev->cont);
-    return &dev->obj;
- }
-
- static void register_my_driver(void)
- {
-     qos_node_create_driver("my_driver", my_driver_constructor);
-     // contained drivers don't need a constructor,
-     // they will be init by the parent.
-     qos_node_create_driver("my_driver_contained", NULL);
-
-    // For the sake of this example, assume machine x86_64/pc contains
-    // "other_node".
-    // This relation, along with the machine and "other_node" creation,
-    // should be defined in the x86_64_pc-machine.c file.
-    // "my_driver" will then consume "other_node"
-    qos_node_contains("my_driver", "my_driver_contained");
-    qos_node_produces("my_driver", "my_interface");
-    qos_node_consumes("my_driver", "other_node");
- }
- *   </programlisting>
- * </example>
- *
- * In the above example, all possible types of relations are created:
- * node "my_driver" consumes, contains and produces other nodes.
- * more specifically:
- * x86_64/pc -->contains--> other_node <--consumes-- my_driver
- *                                                       |
- *                      my_driver_contained <--contains--+
- *                                                       |
- *                             my_interface <--produces--+
- *
- * or inverting the consumes edge in consumed_by:
- *
- * x86_64/pc -->contains--> other_node --consumed_by--> my_driver
- *                                                           |
- *                          my_driver_contained <--contains--+
- *                                                           |
- *                                 my_interface <--produces--+
- *
- * <example>
- *   <title>Creating new test</title>
- *   <programlisting>
- * #include "qgraph.h"
- *
- * static void my_test_function(void *obj, void *data)
- * {
- *    Node_produced *interface_to_test = obj;
- *    // test interface_to_test
- * }
- *
- * static void register_my_test(void)
- * {
- *    qos_add_test("my_interface", "my_test", my_test_function);
- * }
- *
- * libqos_init(register_my_test);
- *
- *   </programlisting>
- * </example>
- *
- * Here a new test is created, consuming "my_interface" node
- * and creating a valid path from a machine to a test.
- * Final graph will be like this:
- * x86_64/pc -->contains--> other_node <--consumes-- my_driver
- *                                                        |
- *                       my_driver_contained <--contains--+
- *                                                        |
- *        my_test --consumes--> my_interface <--produces--+
- *
- * or inverting the consumes edge in consumed_by:
- *
- * x86_64/pc -->contains--> other_node --consumed_by--> my_driver
- *                                                           |
- *                          my_driver_contained <--contains--+
- *                                                           |
- *        my_test <--consumed_by-- my_interface <--produces--+
- *
- * Assuming there the binary is
- * QTEST_QEMU_BINARY=./qemu-system-x86_64
- * a valid test path will be:
- * "/x86_64/pc/other_node/my_driver/my_interface/my_test".
- *
- * Additional examples are also in test-qgraph.c
- *
- * Command line:
- * Command line is built by using node names and optional arguments
- * passed by the user when building the edges.
- *
- * There are three types of command line arguments:
- * - in node      : created from the node name. For example, machines will
- *                  have "-M <machine>" to its command line, while devices
- *                  "-device <device>". It is automatically done by the
- *                   framework.
- * - after node   : added as additional argument to the node name.
- *                  This argument is added optionally when creating edges,
- *                  by setting the parameter @after_cmd_line and
- *                  @extra_edge_opts in #QOSGraphEdgeOptions.
- *                  The framework automatically adds
- *                  a comma before @extra_edge_opts,
- *                  because it is going to add attributes
- *                  after the destination node pointed by
- *                  the edge containing these options, and automatically
- *                  adds a space before @after_cmd_line, because it
- *                  adds an additional device, not an attribute.
- * - before node  : added as additional argument to the node name.
- *                  This argument is added optionally when creating edges,
- *                  by setting the parameter @before_cmd_line in
- *                  #QOSGraphEdgeOptions. This attribute
- *                  is going to add attributes before the destination node
- *                  pointed by the edge containing these options. It is
- *                  helpful to commands that are not node-representable,
- *                  such as "-fdsev" or "-netdev".
- *
- * While adding command line in edges is always used, not all nodes names are
- * used in every path walk: this is because the contained or produced ones
- * are already added by QEMU, so only nodes that "consumes" will be used to
- * build the command line. Also, nodes that will have { "abstract" : true }
- * as QMP attribute will loose their command line, since they are not proper
- * devices to be added in QEMU.
- *
- * Example:
- *
- QOSGraphEdgeOptions opts = {
-     .arg = NULL,
-     .size_arg = 0,
-     .after_cmd_line = "-device other",
-     .before_cmd_line = "-netdev something",
-     .extra_edge_opts = "addr=04.0",
- };
- QOSGraphNode * node = qos_node_create_driver("my_node", constructor);
- qos_node_consumes_args("my_node", "interface", &opts);
- *
- * Will produce the following command line:
- * "-netdev something -device my_node,addr=04.0 -device other"
- */
-
-/**
- * Edge options to be passed to the contains/consumes *_args function.
+ * struct QOSGraphEdgeOptions:
+ * Edge options to be passed to the contains/consumes \*_args function.
+ * @arg: optional arg that will be used by dest edge
+ * @size_arg: @arg size that will be used by dest edge
+ * @extra_device_opts: optional additional command line for dest
+ *                     edge, used to add additional attributes
+ *                     *after* the node command line, the
+ *                     framework automatically prepends ","
+ *                     to this argument.
+ * @before_cmd_line: optional additional command line for dest
+ *                   edge, used to add additional attributes
+ *                   *before* the node command line, usually
+ *                   other non-node represented commands,
+ *                   like "-fdsev synt"
+ * @after_cmd_line: optional extra command line to be added
+ *                  after the device command. This option
+ *                  is used to add other devices
+ *                  command line that depend on current node.
+ *                  Automatically prepends " " to this argument
+ * @edge_name: optional edge to differentiate multiple
+ *             devices with same node name
  */
 struct QOSGraphEdgeOptions {
-    void *arg;                    /*
-                                   * optional arg that will be used by
-                                   * dest edge
-                                   */
-    uint32_t size_arg;            /*
-                                   * optional arg size that will be used by
-                                   * dest edge
-                                   */
-    const char *extra_device_opts;/*
-                                   *optional additional command line for dest
-                                   * edge, used to add additional attributes
-                                   * *after* the node command line, the
-                                   * framework automatically prepends ","
-                                   * to this argument.
-                                   */
-    const char *before_cmd_line;  /*
-                                   * optional additional command line for dest
-                                   * edge, used to add additional attributes
-                                   * *before* the node command line, usually
-                                   * other non-node represented commands,
-                                   * like "-fdsev synt"
-                                   */
-    const char *after_cmd_line;   /*
-                                   * optional extra command line to be added
-                                   * after the device command. This option
-                                   * is used to add other devices
-                                   * command line that depend on current node.
-                                   * Automatically prepends " " to this
-                                   * argument
-                                   */
-    const char *edge_name;        /*
-                                   * optional edge to differentiate multiple
-                                   * devices with same node name
-                                   */
+    void *arg;
+    uint32_t size_arg;
+    const char *extra_device_opts;
+    const char *before_cmd_line;
+    const char *after_cmd_line;
+    const char *edge_name;
 };
 
 /**
+ * struct QOSGraphTestOptions:
  * Test options to be passed to the test functions.
+ * @edge: edge arguments that will be used by test.
+ *        Note that test *does not* use edge_name,
+ *        and uses instead arg and size_arg as
+ *        data arg for its test function.
+ * @arg:  if @before is non-NULL, pass @arg there.
+ *        Otherwise pass it to the test function.
+ * @before: executed before the test. Used to add
+ *          additional parameters to the command line
+ *          and modify the argument to the test function.
+ * @subprocess: run the test in a subprocess.
  */
 struct QOSGraphTestOptions {
-    QOSGraphEdgeOptions edge;   /* edge arguments that will be used by test.
-                                 * Note that test *does not* use edge_name,
-                                 * and uses instead arg and size_arg as
-                                 * data arg for its test function.
-                                 */
-    void *arg;                  /* passed to the .before function, or to the
-                                 * test function if there is no .before
-                                 * function
-                                 */
-    QOSBeforeTest before;       /* executed before the test. Can add
-                                 * additional parameters to the command line
-                                 * and modify the argument to the test function.
-                                 */
-    bool subprocess;            /* run the test in a subprocess */
+    QOSGraphEdgeOptions edge;
+    void *arg;
+    QOSBeforeTest before;
+    bool subprocess;
 };
 
 /**
+ * struct QOSGraphObject:
  * Each driver, test or machine of this framework will have a
  * QOSGraphObject as first field.
  *
  * This set of functions offered by QOSGraphObject are executed
  * in different stages of the framework:
- * - get_driver / get_device : Once a machine-to-test path has been
- * found, the framework traverses it again and allocates all the
- * nodes, using the provided constructor. To satisfy their relations,
- * i.e. for produces or contains, where a struct constructor needs
- * an external parameter represented by the previous node,
- * the framework will call get_device (for contains) or
- * get_driver (for produces), depending on the edge type, passing
- * them the name of the next node to be taken and getting from them
- * the corresponding pointer to the actual structure of the next node to
- * be used in the path.
- *
- * - start_hw: This function is executed after all the path objects
- * have been allocated, but before the test is run. It starts the hw, setting
- * the initial configurations (*_device_enable) and making it ready for the
- * test.
- *
- * - destructor: Opposite to the node constructor, destroys the object.
- * This function is called after the test has been executed, and performs
- * a complete cleanup of each node allocated field. In case no constructor
- * is provided, no destructor will be called.
- *
+ * @get_driver: see @get_device
+ * @get_device: Once a machine-to-test path has been
+ *              found, the framework traverses it again and allocates all the
+ *              nodes, using the provided constructor. To satisfy their
+ *              relations, i.e. for produces or contains, where a struct
+ *              constructor needs an external parameter represented by the
+ *              previous node, the framework will call
+ *              @get_device (for contains) or @get_driver (for produces),
+ *              depending on the edge type, passing them the name of the next
+ *              node to be taken and getting from them the corresponding
+ *              pointer to the actual structure of the next node to
+ *              be used in the path.
+ * @start_hw: This function is executed after all the path objects
+ *            have been allocated, but before the test is run. It starts the
+ *            hw, setting the initial configurations (\*_device_enable) and
+ *            making it ready for the test.
+ * @destructor: Opposite to the node constructor, destroys the object.
+ *              This function is called after the test has been executed, and
+ *              performs a complete cleanup of each node allocated field.
+ *              In case no constructor is provided, no destructor will be
+ *              called.
+ * @free: free the memory associated to the QOSGraphObject and its contained
+ *        children
  */
 struct QOSGraphObject {
-    /* for produces edges, returns void * */
     QOSGetDriver get_driver;
-    /* for contains edges, returns a QOSGraphObject * */
     QOSGetDevice get_device;
-    /* start the hw, get ready for the test */
     QOSStartFunct start_hw;
-    /* destroy this QOSGraphObject */
     QOSDestructorFunc destructor;
-    /* free the memory associated to the QOSGraphObject and its contained
-     * children */
     GDestroyNotify free;
 };
 
@@ -399,24 +152,30 @@ void qos_graph_init(void);
 void qos_graph_destroy(void);
 
 /**
- * qos_node_destroy(): removes and frees a node from the,
+ * qos_node_destroy(): removes and frees a node from the
  * nodes hash table.
+ * @key: Name of the node
  */
 void qos_node_destroy(void *key);
 
 /**
- * qos_edge_destroy(): removes and frees an edge from the,
+ * qos_edge_destroy(): removes and frees an edge from the
  * edges hash table.
+ * @key: Name of the node
  */
 void qos_edge_destroy(void *key);
 
 /**
  * qos_add_test(): adds a test node @name to the nodes hash table.
+ * @name: Name of the test
+ * @interface: Name of the interface node it consumes
+ * @test_func: Actual test to perform
+ * @opts: Facultative options (see %QOSGraphTestOptions)
  *
  * The test will consume a @interface node, and once the
  * graph walking algorithm has found it, the @test_func will be
  * executed. It also has the possibility to
- * add an optional @opts (see %QOSGraphNodeOptions).
+ * add an optional @opts (see %QOSGraphTestOptions).
  *
  * For tests, opts->edge.arg and size_arg represent the arg to pass
  * to @test_func
@@ -428,6 +187,8 @@ void qos_add_test(const char *name, const char *interface,
 /**
  * qos_node_create_machine(): creates the machine @name and
  * adds it to the node hash table.
+ * @name: Name of the machine
+ * @function: Machine constructor
  *
  * This node will be of type QNODE_MACHINE and have @function
  * as constructor
@@ -438,6 +199,9 @@ void qos_node_create_machine(const char *name, QOSCreateMachineFunc function);
  * qos_node_create_machine_args(): same as qos_node_create_machine,
  * but with the possibility to add an optional ", @opts" after -M machine
  * command line.
+ * @name: Name of the machine
+ * @function: Machine constructor
+ * @opts: Optional additional command line
  */
 void qos_node_create_machine_args(const char *name,
                                   QOSCreateMachineFunc function,
@@ -446,6 +210,8 @@ void qos_node_create_machine_args(const char *name,
 /**
  * qos_node_create_driver(): creates the driver @name and
  * adds it to the node hash table.
+ * @name: Name of the driver
+ * @function: Driver constructor
  *
  * This node will be of type QNODE_DRIVER and have @function
  * as constructor
@@ -453,17 +219,17 @@ void qos_node_create_machine_args(const char *name,
 void qos_node_create_driver(const char *name, QOSCreateDriverFunc function);
 
 /**
- * Behaves as qos_node_create_driver() with the extension of allowing to
- * specify a different node name vs. associated QEMU device name.
+ * qos_node_create_driver_named(): behaves as qos_node_create_driver() with the
+ * extension of allowing to specify a different node name vs. associated QEMU
+ * device name.
+ * @name: Custom, unique name of the node to be created
+ * @qemu_name: Actual (official) QEMU driver name the node shall be
+ * associated with
+ * @function: Driver constructor
  *
  * Use this function instead of qos_node_create_driver() if you need to create
  * several instances of the same QEMU device. You are free to choose a custom
  * node name, however the chosen node name must always be unique.
- *
- * @param name: custom, unique name of the node to be created
- * @param qemu_name: actual (official) QEMU driver name the node shall be
- *                   associated with
- * @param function: driver constructor
  */
 void qos_node_create_driver_named(const char *name, const char *qemu_name,
                                   QOSCreateDriverFunc function);
@@ -472,6 +238,9 @@ void qos_node_create_driver_named(const char *name, const char *qemu_name,
  * qos_node_contains(): creates one or more edges of type QEDGE_CONTAINS
  * and adds them to the edge list mapped to @container in the
  * edge hash table.
+ * @container: Source node that "contains"
+ * @contained: Destination node that "is contained"
+ * @opts: Facultative options (see %QOSGraphEdgeOptions)
  *
  * The edges will have @container as source and @contained as destination.
  *
@@ -483,14 +252,17 @@ void qos_node_create_driver_named(const char *name, const char *qemu_name,
  * This function can be useful when there are multiple devices
  * with the same node name contained in a machine/other node
  *
- * For example, if "arm/raspi2" contains 2 "generic-sdhci"
+ * For example, if ``arm/raspi2`` contains 2 ``generic-sdhci``
  * devices, the right commands will be:
- * qos_node_create_machine("arm/raspi2");
- * qos_node_create_driver("generic-sdhci", constructor);
- * //assume rest of the fields are set NULL
- * QOSGraphEdgeOptions op1 = { .edge_name = "emmc" };
- * QOSGraphEdgeOptions op2 = { .edge_name = "sdcard" };
- * qos_node_contains("arm/raspi2", "generic-sdhci", &op1, &op2, NULL);
+ *
+ * .. code::
+ *
+ *    qos_node_create_machine("arm/raspi2");
+ *    qos_node_create_driver("generic-sdhci", constructor);
+ *    // assume rest of the fields are set NULL
+ *    QOSGraphEdgeOptions op1 = { .edge_name = "emmc" };
+ *    QOSGraphEdgeOptions op2 = { .edge_name = "sdcard" };
+ *    qos_node_contains("arm/raspi2", "generic-sdhci", &op1, &op2, NULL);
  *
  * Of course this also requires that the @container's get_device function
  * should implement a case for "emmc" and "sdcard".
@@ -505,6 +277,8 @@ void qos_node_contains(const char *container, const char *contained,
  * qos_node_produces(): creates an edge of type QEDGE_PRODUCES and
  * adds it to the edge list mapped to @producer in the
  * edge hash table.
+ * @producer: Source node that "produces"
+ * @interface: Interface node that "is produced"
  *
  * This edge will have @producer as source and @interface as destination.
  */
@@ -514,6 +288,9 @@ void qos_node_produces(const char *producer, const char *interface);
  * qos_node_consumes():  creates an edge of type QEDGE_CONSUMED_BY and
  * adds it to the edge list mapped to @interface in the
  * edge hash table.
+ * @consumer: Node that "consumes"
+ * @interface: Interface node that "is consumed by"
+ * @opts: Facultative options (see %QOSGraphEdgeOptions)
  *
  * This edge will have @interface as source and @consumer as destination.
  * It also has the possibility to add an optional @opts
@@ -539,7 +316,7 @@ const char *qos_get_current_command_line(void);
 /**
  * qos_allocate_objects():
  * @qts: The #QTestState that will be referred to by the machine object.
- * @alloc: Where to store the allocator for the machine object, or %NULL.
+ * @p_alloc: Where to store the allocator for the machine object, or %NULL.
  *
  * Allocate driver objects for the current test
  * path, but relative to the QTestState @qts.
@@ -551,24 +328,27 @@ void *qos_allocate_objects(QTestState *qts, QGuestAllocator **p_alloc);
 
 /**
  * qos_object_destroy(): calls the destructor for @obj
+ * @obj: A #QOSGraphObject to destroy
  */
 void qos_object_destroy(QOSGraphObject *obj);
 
 /**
  * qos_object_queue_destroy(): queue the destructor for @obj so that it is
  * called at the end of the test
+ * @obj: A #QOSGraphObject to destroy
  */
 void qos_object_queue_destroy(QOSGraphObject *obj);
 
 /**
  * qos_object_start_hw(): calls the start_hw function for @obj
+ * @obj: A #QOSGraphObject containing the start_hw function
  */
 void qos_object_start_hw(QOSGraphObject *obj);
 
 /**
  * qos_machine_new(): instantiate a new machine node
- * @node: A machine node to be instantiated
- * @qts: The #QTestState that will be referred to by the machine object.
+ * @node: Machine node to be instantiated
+ * @qts: A #QTestState that will be referred to by the machine object.
  *
  * Returns a machine object.
  */
@@ -587,8 +367,8 @@ QOSGraphObject *qos_driver_new(QOSGraphNode *node, QOSGraphObject *parent,
                                QGuestAllocator *alloc, void *arg);
 
 /**
- * Just for debugging purpose: prints all currently existing nodes and
- * edges to stdout.
+ * qos_dump_graph(): prints all currently existing nodes and
+ * edges to stdout. Just for debugging purposes.
  *
  * All qtests add themselves to the overall qos graph by calling qgraph
  * functions that add device nodes and edges between the individual graph