27786d709d
Add a rehash() method to EmbeddedResourceManager::Impl to update 'poolSearchList'. Introduce a 'dirty' flag so that EmbeddedResourceManager::Impl::rehash() is automatically called whenever needed. It is not necessary anymore to call EmbeddedResourceManager::selectLocale() after adding resources: changing the EmbeddedResourceManager's locale or adding resources are both operations that set the dirty flag. Whenever someone tries to fetch a resource for the selected locale and the dirty flag is set, a rehash is triggered before the actual fetching so as to ensure it is correct.
103 lines
4.3 KiB
C++
103 lines
4.3 KiB
C++
// -*- coding: utf-8 -*-
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//
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// EmbeddedResourceManager_private.hxx --- Private implementation class for
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// SimGear's EmbeddedResourceManager
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// Copyright (C) 2017 Florent Rougon
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU Library General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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// MA 02110-1301 USA.
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#ifndef FG_EMBEDDEDRESOURCEMANAGERPRIVATE_HXX
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#define FG_EMBEDDEDRESOURCEMANAGERPRIVATE_HXX
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#include <string>
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#include <memory> // std::unique_ptr, std::shared_ptr
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#include <unordered_map>
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#include <vector>
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#include "EmbeddedResource.hxx"
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namespace simgear
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{
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class EmbeddedResourceManager::Impl
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{
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public:
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explicit Impl();
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// Each “locale” for which addResource() has been used has an associated
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// resource pool, that is a sort of directory of all resources declared in
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// this locale. The resource pool for a given locale (e.g., 'fr' or 'de_DE')
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// maps resource virtual paths to the corresponding resource descriptors
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// (via std::shared_ptr<const AbstractEmbeddedResource> instances).
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//
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// Note: for optimal lookup performance, a tree would probably be better,
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// since the expected use for each key here is to store a virtual
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// path. But such an optimization is likely unneeded in most cases.
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typedef std::unordered_map< std::string,
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std::shared_ptr<const AbstractEmbeddedResource> >
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ResourcePool;
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// Return the list of “locales” to scan to implement fallback behavior when
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// fetching a resource for the specified locale. This list will be searched
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// from left to right. Examples:
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//
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// "" -> [""]
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// "fr" -> ["fr", ""]
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// "fr_FR" -> ["fr_FR", "fr", ""]
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static std::vector<std::string> localesSearchList(const std::string& locale);
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// Same as localesSearchList(), except it returns the resource pools instead
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// of the “locale” strings, and only those pools that are not empty.
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std::vector< std::shared_ptr<ResourcePool> > listOfResourcePoolsToSearch(
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const std::string& locale) const;
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// Look up, in each of the pools referred to by 'poolSearchList', the
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// resource associated to 'virtualPath'. Return the first match.
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static std::shared_ptr<const AbstractEmbeddedResource> lookupResourceInPools(
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const std::string& virtualPath,
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const std::vector< std::shared_ptr<ResourcePool> >& poolSearchList);
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// Recompute p->poolSearchList. This method is automatically called whenever
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// needed (lazily), so it doesn't need to be part of the public interface.
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void rehash();
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// Implement the corresponding EmbeddedResourceManager public methods
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std::string getLocale() const;
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std::string selectLocale(const std::string& locale);
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// Ditto
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void addResource(const std::string& virtualPath,
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std::unique_ptr<const AbstractEmbeddedResource> resourcePtr,
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const std::string& locale);
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std::string selectedLocale;
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// Each call to rehash() updates this member to contain precisely the
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// (ordered) list of pools to search for a resource in the selected
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// “locale”. This allows relatively cheap resource lookups, assuming the
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// desired “locale” doesn't change all the time.
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std::vector< std::shared_ptr<ResourcePool> > poolSearchList;
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// Indicate whether 'poolSearchList' must be updated (i.e., resources have
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// been added or the selected locale was changed without rehash() being
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// called afterwards).
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bool dirty;
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// Maps each “locale name” to the corresponding resource pool.
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std::unordered_map< std::string,
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std::shared_ptr<ResourcePool> > localeToResourcePoolMap;
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};
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} // of namespace simgear
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#endif // of FG_EMBEDDEDRESOURCEMANAGERPRIVATE_HXX
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