[pulseaudio-discuss] [PATCH v3 5/6] pactl: Implement list message-handlers

Georg Chini georg at chini.tk
Mon Jan 22 18:12:55 UTC 2018


For better readability, "pactl list message-handlers" is introduced which
prints a formatted output of "pactl send-message /core list-handlers".

The patch also adds the function pa_split_message_parameter_string() for
easy parsing of the message response string.
---
 man/pactl.1.xml.in               |  2 +-
 shell-completion/bash/pulseaudio |  2 +-
 shell-completion/zsh/_pulseaudio |  1 +
 src/pulse/util.c                 | 79 ++++++++++++++++++++++++++++++++++++++++
 src/pulse/util.h                 |  4 ++
 src/utils/pactl.c                | 60 +++++++++++++++++++++++++++++-
 6 files changed, 144 insertions(+), 4 deletions(-)

diff --git a/man/pactl.1.xml.in b/man/pactl.1.xml.in
index 4052fae3..66c0bda9 100644
--- a/man/pactl.1.xml.in
+++ b/man/pactl.1.xml.in
@@ -76,7 +76,7 @@ License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
     <option>
       <p><opt>list</opt> [<arg>short</arg>] [<arg>TYPE</arg>]</p>
       <optdesc><p>Dump all currently loaded modules, available sinks, sources, streams, etc.  <arg>TYPE</arg> must be one of:
-      modules, sinks, sources, sink-inputs, source-outputs, clients, samples, cards.  If not specified, all info is listed.  If
+      modules, sinks, sources, sink-inputs, source-outputs, clients, samples, cards, message-handlers.  If not specified, all info is listed.  If
       short is given, output is in a tabular format, for easy parsing by scripts.</p></optdesc>
     </option>
 
diff --git a/shell-completion/bash/pulseaudio b/shell-completion/bash/pulseaudio
index 797ec067..24d2aa1c 100644
--- a/shell-completion/bash/pulseaudio
+++ b/shell-completion/bash/pulseaudio
@@ -113,7 +113,7 @@ _pactl() {
     local comps
     local flags='-h --help --version -s --server= --client-name='
     local list_types='short sinks sources sink-inputs source-outputs cards
-                    modules samples clients'
+                    modules samples clients message-handlers'
     local commands=(stat info list exit upload-sample play-sample remove-sample
                     load-module unload-module move-sink-input move-source-output
                     suspend-sink suspend-source set-card-profile set-sink-port
diff --git a/shell-completion/zsh/_pulseaudio b/shell-completion/zsh/_pulseaudio
index a2817ebb..c24d0387 100644
--- a/shell-completion/zsh/_pulseaudio
+++ b/shell-completion/zsh/_pulseaudio
@@ -285,6 +285,7 @@ _pactl_completion() {
                 'clients: list connected clients'
                 'samples: list samples'
                 'cards: list available cards'
+                'message-handlers: list available message-handlers'
             )
 
             if ((CURRENT == 2)); then
diff --git a/src/pulse/util.c b/src/pulse/util.c
index 54fe7a28..c3a3320a 100644
--- a/src/pulse/util.c
+++ b/src/pulse/util.c
@@ -342,3 +342,82 @@ int pa_msleep(unsigned long t) {
 #error "Platform lacks a sleep function."
 #endif
 }
+
+/* Split the specified string into elements. An element is defined as
+ * a sub-string between curly braces. The function is needed to parse
+ * the parameters of messages. Each time it is called returns the position
+ * of the next element in start_pos and the length of the element in
+ * length. If max_length is not 0, it is verified that the retrieved
+ * element is within the bounds of the parent element. If the parameter
+ * element is not NULL, a newly allocated string containing the retrieved
+ * element is returned. The caller is responsible to free the string.
+ * The variable state points to, should be initialized to NULL before
+ * the first call. The function returns 1 on success, 0 if end of string
+ * or end of element is encountered and -1 on parse error. */
+int pa_split_message_parameter_string(const char *c, uint32_t max_length, const char **start_pos, uint32_t *length, char **element, const char **state) {
+    const char *current = *state ? *state : c;
+    uint32_t open_braces;
+
+    pa_assert(start_pos);
+    pa_assert(length);
+
+    *start_pos = NULL;
+
+    /* Empty or no string */
+    if (!*current || *c == 0)
+        return 0;
+
+    /* Find opening brace */
+    while (*current != 0) {
+
+        if (*current == '{')
+            break;
+
+        if (*current == '}') {
+
+            /* reached end of element, same as end of string */
+            if (current == c + max_length)
+                return 0;
+
+            /* unexpected closing brace, parse error */
+            return -1;
+        }
+
+        current++;
+    }
+
+    /* No opening brace found, end of string */
+    if (*current == 0)
+         return 0;
+
+    *start_pos = current + 1;
+    open_braces = 1;
+
+    while (open_braces != 0 && *current != 0) {
+        current++;
+        if (*current == '{')
+            open_braces++;
+        if (*current == '}')
+            open_braces--;
+    }
+
+    /* Parse error, closing brace missing */
+    if (open_braces != 0) {
+        *start_pos = NULL;
+        return -1;
+    }
+
+    /* Parse error, access behind end of element */
+    if (max_length && (current > c + max_length)) {
+        *start_pos = NULL;
+        return -1;
+    }
+
+    *state = current + 1;
+    *length = current - *start_pos;
+
+    if (element)
+        *element = pa_xstrndup(*start_pos, *length);
+
+    return 1;
+}
diff --git a/src/pulse/util.h b/src/pulse/util.h
index e4a62da6..94df623f 100644
--- a/src/pulse/util.h
+++ b/src/pulse/util.h
@@ -22,6 +22,7 @@
 ***/
 
 #include <stddef.h>
+#include <inttypes.h>
 
 #include <pulse/cdecl.h>
 #include <pulse/version.h>
@@ -54,6 +55,9 @@ char *pa_path_get_filename(const char *p);
 /** Wait t milliseconds */
 int pa_msleep(unsigned long t);
 
+/** Split message parameter string */
+int pa_split_message_parameter_string(const char *c, uint32_t max_length, const char **start_pos, uint32_t *length, char **element, const char **state);
+
 PA_C_DECL_END
 
 #endif
diff --git a/src/utils/pactl.c b/src/utils/pactl.c
index 66c0f251..edb253d6 100644
--- a/src/utils/pactl.c
+++ b/src/utils/pactl.c
@@ -851,6 +851,53 @@ static void send_message_callback(pa_context *c, int success, const char *respon
     complete_action();
 }
 
+static void list_handlers_callback(pa_context *c, int success, const char *response, void *userdata) {
+    const char *state = NULL;
+    const char *start_pos;
+    uint32_t length;
+    int err;
+
+    if (!success) {
+        pa_log(_("list-handlers message failed: %s"), pa_strerror(pa_context_errno(c)));
+        quit(1);
+        return;
+    }
+
+    while ((err = pa_split_message_parameter_string(response, 0, &start_pos, &length, NULL, &state)) > 0) {
+        const char *state2 = NULL;
+        const char *pos;
+        char *path;
+        char *description;
+        uint32_t max_length = length;
+
+        if (pa_split_message_parameter_string(start_pos, max_length, &pos, &length, &path, &state2) <= 0) {
+            err = -1;
+            break;
+        }
+        if (pa_split_message_parameter_string(start_pos, max_length, &pos, &length, &description, &state2) <= 0) {
+            pa_xfree(path);
+            err = -1;
+            break;
+        }
+
+        if (short_list_format)
+            printf("%s\n", path);
+        else
+            printf("Message Handler %s\n        Description: %s\n", path, description);
+
+        pa_xfree(path);
+        pa_xfree(description);
+    }
+
+    if (err < 0) {
+        pa_log(_("list-handlers message response could not be parsed correctly"));
+        quit(1);
+        return;
+    }
+
+    complete_action();
+}
+
 static void volume_relative_adjust(pa_cvolume *cv) {
     pa_assert(volume_flags & VOL_RELATIVE);
 
@@ -1262,6 +1309,8 @@ static void context_state_callback(pa_context *c, void *userdata) {
                             o = pa_context_get_sample_info_list(c, get_sample_info_callback, NULL);
                         else if (pa_streq(list_type, "cards"))
                             o = pa_context_get_card_info_list(c, get_card_info_callback, NULL);
+                        else if (pa_streq(list_type, "message-handlers"))
+                            o = pa_context_send_message_to_object(c, "/core", "list-handlers", NULL, list_handlers_callback, NULL);
                         else
                             pa_assert_not_reached();
                     } else {
@@ -1312,6 +1361,12 @@ static void context_state_callback(pa_context *c, void *userdata) {
                             actions++;
                         }
 
+                        o = pa_context_send_message_to_object(c, "/core", "list-handlers", NULL, list_handlers_callback, NULL);
+                        if (o) {
+                            pa_operation_unref(o);
+                            actions++;
+                        }
+
                         o = NULL;
                     }
                     break;
@@ -1698,12 +1753,13 @@ int main(int argc, char *argv[]) {
                 if (pa_streq(argv[i], "modules") || pa_streq(argv[i], "clients") ||
                     pa_streq(argv[i], "sinks")   || pa_streq(argv[i], "sink-inputs") ||
                     pa_streq(argv[i], "sources") || pa_streq(argv[i], "source-outputs") ||
-                    pa_streq(argv[i], "samples") || pa_streq(argv[i], "cards")) {
+                    pa_streq(argv[i], "samples") || pa_streq(argv[i], "cards") ||
+                    pa_streq(argv[i], "message-handlers")) {
                     list_type = pa_xstrdup(argv[i]);
                 } else if (pa_streq(argv[i], "short")) {
                     short_list_format = true;
                 } else {
-                    pa_log(_("Specify nothing, or one of: %s"), "modules, sinks, sources, sink-inputs, source-outputs, clients, samples, cards");
+                    pa_log(_("Specify nothing, or one of: %s"), "modules, sinks, sources, sink-inputs, source-outputs, clients, samples, cards, message-handlers");
                     goto quit;
                 }
             }
-- 
2.14.1



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