DirectoryWalker.h

   1 //
   2 // Copyright 2011 The Android Open Source Project
   3 //
   4 // Defines an abstraction for opening a directory on the filesystem and
   5 // iterating through it.
   6
   7 #ifndef DIRECTORYWALKER_H
   8 #define DIRECTORYWALKER_H
   9
  10 #include <dirent.h>
  11 #include <sys/types.h>
  12 #include <sys/param.h>
  13 #include <sys/stat.h>
  14 #include <unistd.h>
  15 #include <utils/String8.h>
  16
  17 #include <stdio.h>
  18
  19 using namespace android;
  20
  21 // Directory Walker
  22 // This is an abstraction for walking through a directory and getting files
  23 // and descriptions.
  24
  25 class DirectoryWalker {
  26 public:
  27     virtual ~DirectoryWalker() {};
  28     virtual bool openDir(String8 path) = 0;
  29     virtual bool openDir(const char* path) = 0;
  30     // Advance to next directory entry
  31     virtual struct dirent* nextEntry() = 0;
  32     // Get the stats for the current entry
  33     virtual struct stat*   entryStats() = 0;
  34     // Clean Up
  35     virtual void closeDir() = 0;
  36     // This class is able to replicate itself on the heap
  37     virtual DirectoryWalker* clone() = 0;
  38
  39     // DATA MEMBERS
  40     // Current directory entry
  41     struct dirent mEntry;
  42     // Stats for that directory entry
  43     struct stat mStats;
  44     // Base path
  45     String8 mBasePath;
  46 };
  47
  48 // System Directory Walker
  49 // This is an implementation of the above abstraction that calls
  50 // real system calls and is fully functional.
  51 // functions are inlined since they're very short and simple
  52
  53 class SystemDirectoryWalker : public DirectoryWalker {
  54
  55     // Default constructor, copy constructor, and destructor are fine
  56 public:
  57     virtual bool openDir(String8 path) {
  58         mBasePath = path;
  59         dir = NULL;
  60         dir = opendir(mBasePath.string() );
  61
  62         if (dir == NULL)
  63             return false;
  64
  65         return true;
  66     };
  67     virtual bool openDir(const char* path) {
  68         String8 p(path);
  69         openDir(p);
  70         return true;
  71     };
  72     // Advance to next directory entry
  73     virtual struct dirent* nextEntry() {
  74         struct dirent* entryPtr = readdir(dir);
  75         if (entryPtr == NULL)
  76             return NULL;
  77
  78         mEntry = *entryPtr;
  79         // Get stats
  80         String8 fullPath = mBasePath.appendPathCopy(mEntry.d_name);
  81         stat(fullPath.string(),&mStats);
  82         return &mEntry;
  83     };
  84     // Get the stats for the current entry
  85     virtual struct stat*   entryStats() {
  86         return &mStats;
  87     };
  88     virtual void closeDir() {
  89         closedir(dir);
  90     };
  91     virtual DirectoryWalker* clone() {
  92         return new SystemDirectoryWalker(*this);
  93     };
  94 private:
  95     DIR* dir;
  96 };
  97
  98 #endif // DIRECTORYWALKER_H