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authorEelco Dolstra <eelco.dolstra@logicblox.com>2016-02-04T13·28+0100
committerEelco Dolstra <eelco.dolstra@logicblox.com>2016-02-04T13·28+0100
commitc10c61449f954702ae6d8092120321744acd82ff (patch)
tree40c161c42301acdfbfd7786638293951c5baf54d /src/libutil/util.hh
parent4f7824c58ee0420c5679be6f0a9591f59edf410f (diff)
Eliminate the "store" global variable
Also, move a few free-standing functions into StoreAPI and Derivation.

Also, introduce a non-nullable smart pointer, ref<T>, which is just a
wrapper around std::shared_ptr ensuring that the pointer is never
null. (For reference-counted values, this is better than passing a
"T&", because the latter doesn't maintain the refcount. Usually, the
caller will have a shared_ptr keeping the value alive, but that's not
always the case, e.g., when passing a reference to a std::thread via
std::bind.)
Diffstat (limited to 'src/libutil/util.hh')
-rw-r--r--src/libutil/util.hh10
1 files changed, 10 insertions, 0 deletions
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index a889ef2f14fa..b714cdc64a5a 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -413,4 +413,14 @@ string base64Encode(const string & s);
 string base64Decode(const string & s);
 
 
+/* Get a value for the specified key from an associate container, or a
+   default value if the key doesn't exist. */
+template <class T>
+string get(const T & map, const string & key, const string & def = "")
+{
+    auto i = map.find(key);
+    return i == map.end() ? def : i->second;
+}
+
+
 }