1//
2// Copyright 2011 The Android Open Source Project
3//
4// Abstraction of calls to system to make directories and delete files and
5// wrapper to image processing.
6
7#ifndef CACHE_UPDATER_H
8#define CACHE_UPDATER_H
9
10#include <utils/String8.h>
11#include <sys/types.h>
12#include <sys/stat.h>
13#include <stdio.h>
14#include "Images.h"
15#ifdef HAVE_MS_C_RUNTIME
16#include <direct.h>
17#endif
18
19using namespace android;
20
21/** CacheUpdater
22 *  This is a pure virtual class that declares abstractions of functions useful
23 *  for managing a cache files. This manager is set up to be used in a
24 *  mirror cache where the source tree is duplicated and filled with processed
25 *  images. This class is abstracted to allow for dependency injection during
26 *  unit testing.
27 *  Usage:
28 *      To update/add a file to the cache, call processImage
29 *      To remove a file from the cache, call deleteFile
30 */
31class CacheUpdater {
32public:
33    virtual ~CacheUpdater() {}
34
35    // Make sure all the directories along this path exist
36    virtual void ensureDirectoriesExist(String8 path) = 0;
37
38    // Delete a file
39    virtual void deleteFile(String8 path) = 0;
40
41    // Process an image from source out to dest
42    virtual void processImage(String8 source, String8 dest) = 0;
43private:
44};
45
46/** SystemCacheUpdater
47 * This is an implementation of the above virtual cache updater specification.
48 * This implementations hits the filesystem to manage a cache and calls out to
49 * the PNG crunching in images.h to process images out to its cache components.
50 */
51class SystemCacheUpdater : public CacheUpdater {
52public:
53    // Constructor to set bundle to pass to preProcessImage
54    SystemCacheUpdater (Bundle* b)
55        : bundle(b) { };
56
57    // Make sure all the directories along this path exist
58    virtual void ensureDirectoriesExist(String8 path)
59    {
60        // Check to see if we're dealing with a fully qualified path
61        String8 existsPath;
62        String8 toCreate;
63        String8 remains;
64        struct stat s;
65
66        // Check optomistically to see if all directories exist.
67        // If something in the path doesn't exist, then walk the path backwards
68        // and find the place to start creating directories forward.
69        if (stat(path.string(),&s) == -1) {
70            // Walk backwards to find place to start creating directories
71            existsPath = path;
72            do {
73                // As we remove the end of existsPath add it to
74                // the string of paths to create.
75                toCreate = existsPath.getPathLeaf().appendPath(toCreate);
76                existsPath = existsPath.getPathDir();
77            } while (stat(existsPath.string(),&s) == -1);
78
79            // Walk forwards and build directories as we go
80            do {
81                // Advance to the next segment of the path
82                existsPath.appendPath(toCreate.walkPath(&remains));
83                toCreate = remains;
84#ifdef HAVE_MS_C_RUNTIME
85                _mkdir(existsPath.string());
86#else
87                mkdir(existsPath.string(), S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP);
88#endif
89            } while (remains.length() > 0);
90        } //if
91    };
92
93    // Delete a file
94    virtual void deleteFile(String8 path)
95    {
96        if (remove(path.string()) != 0)
97            fprintf(stderr,"ERROR DELETING %s\n",path.string());
98    };
99
100    // Process an image from source out to dest
101    virtual void processImage(String8 source, String8 dest)
102    {
103        // Make sure we're trying to write to a directory that is extant
104        ensureDirectoriesExist(dest.getPathDir());
105
106        preProcessImageToCache(bundle, source, dest);
107    };
108private:
109    Bundle* bundle;
110};
111
112#endif // CACHE_UPDATER_H
113