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1 // Copyright 2016 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef CHROMEOS_PRINTING_PPD_CACHE_H_ | |
6 #define CHROMEOS_PRINTING_PPD_CACHE_H_ | |
7 | |
8 #include <memory> | |
9 #include <string> | |
10 | |
11 #include "base/files/file_path.h" | |
12 #include "base/optional.h" | |
13 #include "chromeos/chromeos_export.h" | |
14 #include "chromeos/printing/printer_configuration.h" | |
15 | |
16 namespace chromeos { | |
17 namespace printing { | |
18 | |
19 // PpdCache manages a cache of locally-stored PPD files. At its core, it | |
20 // operates like a persistent hash from PpdReference to files. If you give the | |
21 // same PpdReference to Find() that was previously given to store, you should | |
22 // get the same FilePath back out (unless the previous entry has timed out of | |
23 // the cache). However, changing *any* field in PpdReference will make the | |
24 // previous cache entry invalid. This is the intentional behavior -- we want to | |
25 // re-run the resolution logic if we have new meta-information about a printer. | |
26 class CHROMEOS_EXPORT PpdCache { | |
27 public: | |
28 // Create and return a Ppdcache that uses cache_dir to store state. | |
29 static std::unique_ptr<PpdCache> Create(const base::FilePath& cache_base_dir); | |
30 virtual ~PpdCache() {} | |
31 | |
32 // Find a PPD that was previously cached with the given reference. Note that | |
33 // all fields of the reference must be the same, otherwise we'll miss in the | |
34 // cache and re-run resolution for the PPD. | |
35 // | |
36 // If a FilePath is returned, it is guaranteed to be non-empty and | |
37 // remain valid until the next Store() call. | |
38 virtual base::Optional<base::FilePath> Find( | |
39 const Printer::PpdReference& reference) const = 0; | |
40 | |
41 // Take the contents of a ppd file, store it to the cache, and return the | |
Lei Zhang
2016/10/19 01:25:10
more s/ppd/PPD/
Carlson
2016/10/19 16:38:26
Done.
| |
42 // path to the stored file keyed on reference. | |
43 // | |
44 // If a different ppd was previously Stored for the given reference, it | |
45 // will be replaced. | |
46 // | |
47 // On success, the returned FilePath is guaranteed to be non-empty | |
48 // and remain valid until the next Store* call. | |
49 virtual base::Optional<base::FilePath> Store( | |
50 const Printer::PpdReference& reference, | |
51 const std::string& ppd_contents) = 0; | |
52 }; | |
53 | |
54 } // namespace printing | |
55 } // namespace chromeos | |
56 | |
57 #endif // CHROMEOS_PRINTING_PPD_CACHE_H_ | |
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