modargs: Add a mechanism to append modargs

This allows us to parse an extra set of modargs to tack on to an
existing set. Duplicates in the second set are ignored, since this fits
our use best. In the future, this could be extended to support different
merge modes (ignore dupes vs. replace with dupes), but I've left this
out since there isn't a clear need and it would be dead code for now.

2 files changed, 38 insertions, 18 deletions

diff --git a/src/pulsecore/modargs.c b/src/pulsecore/modargs.c
index b3c0313f3..bce5891db 100644
--- a/src/pulsecore/modargs.c
+++ b/src/pulsecore/modargs.c
@@ -43,7 +43,7 @@ struct entry {
     char *key, *value;
 };
 
-static int add_key_value(pa_modargs *ma, char *key, char *value, const char* const valid_keys[]) {
+static int add_key_value(pa_modargs *ma, char *key, char *value, const char* const valid_keys[], bool ignore_dupes) {
     struct entry *e;
     char *raw;
 
@@ -56,7 +56,11 @@ static int add_key_value(pa_modargs *ma, char *key, char *value, const char* con
     if (pa_hashmap_get(ma->unescaped, key)) {
         pa_xfree(key);
         pa_xfree(value);
-        return -1;
+
+        if (ignore_dupes)
+            return 0;
+        else
+            return -1;
     }
 
     if (valid_keys) {
@@ -100,7 +104,7 @@ static void free_func(void *p) {
     pa_xfree(e);
 }
 
-pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
+static int parse(pa_modargs *ma, const char *args, const char* const* valid_keys, bool ignore_dupes) {
     enum {
         WHITESPACE,
         KEY,
@@ -115,13 +119,6 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
 
     const char *p, *key = NULL, *value = NULL;
     size_t key_len = 0, value_len = 0;
-    pa_modargs *ma = pa_xnew(pa_modargs, 1);
-
-    ma->raw = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, free_func);
-    ma->unescaped = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, free_func);
-
-    if (!args)
-        return ma;
 
     state = WHITESPACE;
 
@@ -160,7 +157,8 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
                     if (add_key_value(ma,
                                       pa_xstrndup(key, key_len),
                                       pa_xstrdup(""),
-                                      valid_keys) < 0)
+                                      valid_keys,
+                                      ignore_dupes) < 0)
                         goto fail;
                     state = WHITESPACE;
                 } else if (*p == '\\') {
@@ -179,7 +177,8 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
                     if (add_key_value(ma,
                                       pa_xstrndup(key, key_len),
                                       pa_xstrndup(value, value_len),
-                                      valid_keys) < 0)
+                                      valid_keys,
+                                      ignore_dupes) < 0)
                         goto fail;
                     state = WHITESPACE;
                 } else if (*p == '\\') {
@@ -199,7 +198,8 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
                     if (add_key_value(ma,
                                       pa_xstrndup(key, key_len),
                                       pa_xstrndup(value, value_len),
-                                      valid_keys) < 0)
+                                      valid_keys,
+                                      ignore_dupes) < 0)
                         goto fail;
                     state = WHITESPACE;
                 } else if (*p == '\\') {
@@ -219,7 +219,8 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
                     if (add_key_value(ma,
                                       pa_xstrndup(key, key_len),
                                       pa_xstrndup(value, value_len),
-                                      valid_keys) < 0)
+                                      valid_keys,
+                                      ignore_dupes) < 0)
                         goto fail;
                     state = WHITESPACE;
                 } else if (*p == '\\') {
@@ -237,23 +238,40 @@ pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
     }
 
     if (state == VALUE_START) {
-        if (add_key_value(ma, pa_xstrndup(key, key_len), pa_xstrdup(""), valid_keys) < 0)
+        if (add_key_value(ma, pa_xstrndup(key, key_len), pa_xstrdup(""), valid_keys, ignore_dupes) < 0)
             goto fail;
     } else if (state == VALUE_SIMPLE) {
-        if (add_key_value(ma, pa_xstrndup(key, key_len), pa_xstrdup(value), valid_keys) < 0)
+        if (add_key_value(ma, pa_xstrndup(key, key_len), pa_xstrdup(value), valid_keys, ignore_dupes) < 0)
             goto fail;
     } else if (state != WHITESPACE)
         goto fail;
 
-    return ma;
+    return 0;
 
 fail:
+    return -1;
+}
 
-    pa_modargs_free(ma);
+pa_modargs *pa_modargs_new(const char *args, const char* const* valid_keys) {
+    pa_modargs *ma = pa_xnew(pa_modargs, 1);
+
+    ma->raw = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, free_func);
+    ma->unescaped = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, free_func);
+
+    if (args && parse(ma, args, valid_keys, false) < 0)
+        goto fail;
 
+    return ma;
+
+fail:
+    pa_modargs_free(ma);
     return NULL;
 }
 
+int pa_modargs_append(pa_modargs *ma, const char *args, const char* const* valid_keys) {
+    return parse(ma, args, valid_keys, true);
+}
+
 void pa_modargs_free(pa_modargs*ma) {
     pa_assert(ma);
 
diff --git a/src/pulsecore/modargs.h b/src/pulsecore/modargs.h
index 776a1e6fb..50cf6c5d9 100644
--- a/src/pulsecore/modargs.h
+++ b/src/pulsecore/modargs.h
@@ -34,6 +34,8 @@ typedef struct pa_modargs pa_modargs;
 
 /* Parse the string args. The NULL-terminated array keys contains all valid arguments. */
 pa_modargs *pa_modargs_new(const char *args, const char* const keys[]);
+/* Parse the string args, and add any keys that are not already present. */
+int pa_modargs_append(pa_modargs *ma, const char *args, const char* const* valid_keys);
 void pa_modargs_free(pa_modargs*ma);
 
 /* Return the module argument for the specified name as a string. If