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CompositeStorage.hxx
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1 /*
2 * Copyright 2003-2017 The Music Player Daemon Project
3 * http://www.musicpd.org
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #ifndef MPD_COMPOSITE_STORAGE_HXX
21 #define MPD_COMPOSITE_STORAGE_HXX
22
23 #include "check.h"
24 #include "StorageInterface.hxx"
25 #include "thread/Mutex.hxx"
26 #include "Compiler.h"
27
28 #include <string>
29 #include <map>
30
39 class CompositeStorage final : public Storage {
43 struct Directory {
50 Storage *storage;
51
52 std::map<std::string, Directory> children;
53
54 Directory():storage(nullptr) {}
55 ~Directory();
56
57 gcc_pure
58 bool IsEmpty() const {
59 return storage == nullptr && children.empty();
60 }
61
62 gcc_pure
63 const Directory *Find(const char *uri) const;
64
65 Directory &Make(const char *uri);
66
67 bool Unmount();
68 bool Unmount(const char *uri);
69
70 gcc_pure
71 bool MapToRelativeUTF8(std::string &buffer,
72 const char *uri) const;
73 };
74
75 struct FindResult {
76 const Directory *directory;
77 const char *uri;
78 };
79
85 mutable Mutex mutex;
86
87 Directory root;
88
89 mutable std::string relative_buffer;
90
91 public:
92 CompositeStorage();
93 virtual ~CompositeStorage();
94
103 gcc_pure gcc_nonnull_all
104 Storage *GetMount(const char *uri);
105
111 template<typename T>
112 void VisitMounts(T t) const {
113 const std::lock_guard<Mutex> protect(mutex);
114 std::string uri;
115 VisitMounts(uri, root, t);
116 }
117
118 void Mount(const char *uri, Storage *storage);
119 bool Unmount(const char *uri);
120
121 /* virtual methods from class Storage */
122 StorageFileInfo GetInfo(const char *uri, bool follow) override;
123
124 StorageDirectoryReader *OpenDirectory(const char *uri) override;
125
126 std::string MapUTF8(const char *uri) const override;
127
128 AllocatedPath MapFS(const char *uri) const override;
129
130 const char *MapToRelativeUTF8(const char *uri) const override;
131
132 private:
133 template<typename T>
134 void VisitMounts(std::string &uri, const Directory &directory,
135 T t) const {
136 const Storage *const storage = directory.storage;
137 if (storage != nullptr)
138 t(uri.c_str(), *storage);
139
140 if (!uri.empty())
141 uri.push_back('/');
142
143 const size_t uri_length = uri.length();
144
145 for (const auto &i : directory.children) {
146 uri.resize(uri_length);
147 uri.append(i.first);
148
149 VisitMounts(uri, i.second, t);
150 }
151 }
152
161 gcc_pure
162 FindResult FindStorage(const char *uri) const;
163
164 const char *MapToRelativeUTF8(const Directory &directory,
165 const char *uri) const;
166 };
167
168 #endif
CompositeStorage::MapUTF8
std::string MapUTF8(const char *uri) const override
Map the given relative URI to an absolute URI.
check.h
CompositeStorage::Unmount
bool Unmount(const char *uri)
gcc_nonnull_all
#define gcc_nonnull_all
Definition: Compiler.h:122
AllocatedPath
A path name in the native file system character set.
Definition: AllocatedPath.hxx:38
Storage
Definition: StorageInterface.hxx:46
CompositeStorage::Mount
void Mount(const char *uri, Storage *storage)
CompositeStorage::OpenDirectory
StorageDirectoryReader * OpenDirectory(const char *uri) override
Throws #std::runtime_error on error.
Mutex
Definition: Mutex.hxx:43
StorageFileInfo
Definition: FileInfo.hxx:28
CompositeStorage::~CompositeStorage
virtual ~CompositeStorage()
CompositeStorage::CompositeStorage
CompositeStorage()
CompositeStorage::GetInfo
StorageFileInfo GetInfo(const char *uri, bool follow) override
Throws #std::runtime_error on error.
Compiler.h
storage
const Storage & storage
Definition: DatabasePlaylist.hxx:31
StorageInterface.hxx
StorageDirectoryReader
Definition: StorageInterface.hxx:31
Mutex.hxx
CompositeStorage::VisitMounts
void VisitMounts(T t) const
Call the given function for each mounted storage, including the root storage.
Definition: CompositeStorage.hxx:112
Directory::Directory
Directory(std::string &&_path_utf8, Directory *_parent)
CompositeStorage
A Storage implementation that combines multiple other Storage instances in one virtual tree...
Definition: CompositeStorage.hxx:39
CompositeStorage::GetMount
gcc_pure gcc_nonnull_all Storage * GetMount(const char *uri)
Get the Storage at the specified mount point.
gcc_pure
#define gcc_pure
Definition: Compiler.h:116
Directory
Definition: Directory.hxx:49
uri
const Storage const char * uri
Definition: DatabasePlaylist.hxx:31
CompositeStorage::MapFS
AllocatedPath MapFS(const char *uri) const override
Map the given relative URI to a local file path.
CompositeStorage::MapToRelativeUTF8
const char * MapToRelativeUTF8(const char *uri) const override
Check if the given URI points inside this storage.