Add EndIteration method to free memory allocated

in StartIteration. This method should always be called when the
iteration is over to make sure that we don't leak memory.

Change-Id: I5205c754dfafbab9bb5f06003c3663d2ec4e8a35

include/ziparchive/zip_archive.h

@@ -130,10 +130,10 @@ int32_t FindEntry(const ZipArchiveHandle handle, const char* entryName,
 /*
  * Start iterating over all entries of a zip file. The order of iteration
  * is not guaranteed to be the same as the order of elements
- * in the central directory but is stable for a given zip file. |cookie|
- * must point to a writeable memory location, and will be set to the value
- * of an opaque cookie which can be used to make one or more calls to
- * Next.
+ * in the central directory but is stable for a given zip file. |cookie| will
+ * contain the value of an opaque cookie which can be used to make one or more
+ * calls to Next. All calls to StartIteration must be matched by a call to
+ * EndIteration to free any allocated memory.
  *
  * This method also accepts an optional prefix to restrict iteration to
  * entry names that start with |prefix|.
@@ -151,6 +151,12 @@ int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr,
  */
 int32_t Next(void* cookie, ZipEntry* data, ZipEntryName *name);
 
+/*
+ * End iteration over all entries of a zip file and frees the memory allocated
+ * in StartIteration.
+ */
+void EndIteration(void* cookie);
+
 /*
  * Uncompress and write an entry to an open file identified by |fd|.
  * |entry->uncompressed_length| bytes will be written to the file at

libziparchive/zip_archive.cc

@@ -909,6 +909,12 @@ int32_t StartIteration(ZipArchiveHandle handle, void** cookie_ptr, const char* p
   return 0;
 }
 
+void EndIteration(void* cookie) {
+  if (cookie != NULL) {
+    free(cookie);
+  }
+}
+
 int32_t FindEntry(const ZipArchiveHandle handle, const char* entryName,
                   ZipEntry* data) {
   const ZipArchive* archive = (ZipArchive*) handle;