rewrite map loader

src/FileContentsCache.cc

@@ -11,27 +11,26 @@ using namespace std;
 
 FileContentsCache::FileContentsCache(uint64_t ttl_usecs) : ttl_usecs(ttl_usecs) { }
 
-FileContentsCache::File::File(const string& name, shared_ptr<const string> contents,
-    uint64_t load_time) : name(name), contents(contents), load_time(load_time) { }
+FileContentsCache::File::File(
+    const string& name,
+    string&& data,
+    uint64_t load_time)
+  : name(name), data(move(data)), load_time(load_time) { }
 
-shared_ptr<const string> FileContentsCache::replace(
+shared_ptr<const FileContentsCache::File> FileContentsCache::replace(
     const string& name, string&& data, uint64_t t) {
   if (t == 0) {
     t = now();
   }
-  shared_ptr<const string> contents(new string(move(data)));
-  auto emplace_ret = this->name_to_file.emplace(
-      piecewise_construct,
-      forward_as_tuple(name),
-      forward_as_tuple(name, contents, t));
+  shared_ptr<File> new_file(new File(name, move(data), t));
+  auto emplace_ret = this->name_to_file.emplace(name, new_file);
   if (!emplace_ret.second) {
-    emplace_ret.first->second.contents = contents;
-    emplace_ret.first->second.load_time = t;
+    emplace_ret.first->second = new_file;
   }
-  return contents;
+  return new_file;
 }
 
-shared_ptr<const string> FileContentsCache::replace(
+shared_ptr<const FileContentsCache::File> FileContentsCache::replace(
     const string& name, const void* data, size_t size, uint64_t t) {
   string s(reinterpret_cast<const char*>(data), size);
   return this->replace(name, move(s), t);
@@ -45,14 +44,16 @@ FileContentsCache::GetResult FileContentsCache::get_or_load(const char* name) {
   return this->get_or_load(string(name));
 }
 
-shared_ptr<const string> FileContentsCache::get_or_throw(const std::string& name) {
+shared_ptr<const FileContentsCache::File> FileContentsCache::get_or_throw(
+    const std::string& name) {
   auto throw_fn = +[](const std::string&) -> string {
     throw out_of_range("file missing from cache");
   };
-  return this->get(name, throw_fn).data;
+  return this->get(name, throw_fn).file;
 }
 
-shared_ptr<const string> FileContentsCache::get_or_throw(const char* name) {
+shared_ptr<const FileContentsCache::File> FileContentsCache::get_or_throw(
+    const char* name) {
   return this->get_or_throw(string(name));
 }
 
@@ -61,8 +62,8 @@ FileContentsCache::GetResult FileContentsCache::get(const std::string& name,
   uint64_t t = now();
   try {
     auto& entry = this->name_to_file.at(name);
-    if (this->ttl_usecs && (t - entry.load_time < this->ttl_usecs)) {
-      return {entry.contents, false};
+    if (this->ttl_usecs && (t - entry->load_time < this->ttl_usecs)) {
+      return {entry, false};
     }
   } catch (const out_of_range& e) { }
   return {this->replace(name, generate(name)), true};