From 296b9e3a25c2f34d9f91936ef7cac661bd5fc502 Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Thu, 5 Dec 2013 21:40:36 +0100
Subject: [PATCH] Start implementation of the cat command

---
 kernel/include/disks.hpp |  2 ++
 kernel/include/fat32.hpp |  3 +-
 kernel/include/pair.hpp  | 62 +++++++++++++++++++++++++++++++++++++++
 kernel/include/utils.hpp |  9 ++++--
 kernel/src/disks.cpp     | 10 ++++++-
 kernel/src/fat32.cpp     | 63 +++++++++++++++++++++++++---------------
 kernel/src/shell.cpp     | 12 +++++++-
 7 files changed, 132 insertions(+), 29 deletions(-)
 create mode 100644 kernel/include/pair.hpp

diff --git a/kernel/include/disks.hpp b/kernel/include/disks.hpp
index 0e4aefe1..e10504e7 100644
--- a/kernel/include/disks.hpp
+++ b/kernel/include/disks.hpp
@@ -66,6 +66,8 @@ void unmount();
 vector<file> ls();
 uint64_t free_size();
 
+string read_file(const string& file);
+
 const disk_descriptor* mounted_disk();
 const partition_descriptor* mounted_partition();
 
diff --git a/kernel/include/fat32.hpp b/kernel/include/fat32.hpp
index 62264923..b07ea1e6 100644
--- a/kernel/include/fat32.hpp
+++ b/kernel/include/fat32.hpp
@@ -9,8 +9,9 @@ namespace fat32 {
 
 typedef const disks::disk_descriptor& dd;
 
-vector<disks::file> ls(dd disk, const disks::partition_descriptor& partition, const vector<string>& path);
 uint64_t free_size(dd disk, const disks::partition_descriptor& partition);
+vector<disks::file> ls(dd disk, const disks::partition_descriptor& partition, const vector<string>& path);
+string read_file(dd disk, const disks::partition_descriptor& partition, const vector<string>& path, const string& file);
 
 }
 
diff --git a/kernel/include/pair.hpp b/kernel/include/pair.hpp
new file mode 100644
index 00000000..39e386e2
--- /dev/null
+++ b/kernel/include/pair.hpp
@@ -0,0 +1,62 @@
+#ifndef PAIR_H
+#define PAIR_H
+
+template<typename T1, typename T2>
+class pair {
+public:
+    typedef T1 first_type;
+    typedef T2 second_type;
+
+    first_type first;
+    second_type second;
+
+    //Constructor
+
+    constexpr pair(const first_type& a, const second_type& b) : first(a), second(b){
+        //Nothing to init
+    }
+
+    template<typename U1, typename U2>
+    constexpr pair(U1&& x, U2&& y) : first(forward<U1>(x)), second(forward<U2>(y)){
+        //Nothing to init
+    }
+
+    //Copy constructors
+
+    constexpr pair(const pair&) = default;
+
+    template<typename U1, typename U2>
+    constexpr pair(const pair<U1, U2>& p) : first(p.first), second(p.second) {
+        //Nothing to init
+    }
+
+    template<typename U1, typename U2>
+    pair& operator=(const pair<U1, U2>& p){
+        first = p.first;
+        second = p.second;
+        return *this;
+    }
+
+    //Move constructors
+
+    constexpr pair(pair&&) = default;
+
+    template<typename U1, typename U2>
+    constexpr pair(pair<U1, U2>&& p) : first(move(p.first)), second((p.second)) {
+        //Nothing to init
+    }
+
+    template<typename U1, typename U2>
+    pair& operator=(pair<U1, U2>&& p){
+        first = forward<U1>(p.first);
+        second = forward<U2>(p.second);
+        return *this;
+    }
+};
+
+template<typename T1, typename T2>
+inline constexpr pair<T1, T2> make_pair(T1&& x, T2&& y){
+    return pair<T1, T2>(forward<T1>(x), forward<T2>(y));
+}
+
+#endif
diff --git a/kernel/include/utils.hpp b/kernel/include/utils.hpp
index 285caad0..690d6564 100644
--- a/kernel/include/utils.hpp
+++ b/kernel/include/utils.hpp
@@ -39,9 +39,14 @@ template< class T > struct remove_reference      {typedef T type;};
 template< class T > struct remove_reference<T&>  {typedef T type;};
 template< class T > struct remove_reference<T&&> {typedef T type;};
 
-template< class T >
-constexpr typename remove_reference<T>::type&& move( T&& t ){
+template<typename T>
+constexpr typename remove_reference<T>::type&& move(T&& t){
     return static_cast<typename remove_reference<T>::type&&>(t);
 }
 
+template<typename T>
+constexpr T&& forward(typename remove_reference<T>::type& t ){
+    return static_cast<T&&>(t);
+}
+
 #endif
diff --git a/kernel/src/disks.cpp b/kernel/src/disks.cpp
index 2730b271..94ebd99e 100644
--- a/kernel/src/disks.cpp
+++ b/kernel/src/disks.cpp
@@ -228,6 +228,14 @@ uint64_t disks::free_size(){
     return fat32::free_size(*_mounted_disk, *_mounted_partition);
 }
 
-const vector<string>& disks::current_directory(){
+vector<string>& disks::current_directory(){
     return pwd;
 }
+
+string disks::read_file(const string& file){
+    if(!_mounted_disk || !_mounted_partition){
+        return "";
+    }
+
+    return fat32::read_file(*_mounted_disk, *_mounted_partition, pwd, file);
+}
diff --git a/kernel/src/fat32.cpp b/kernel/src/fat32.cpp
index f179f7a2..1431b7d3 100644
--- a/kernel/src/fat32.cpp
+++ b/kernel/src/fat32.cpp
@@ -4,6 +4,7 @@
 #include "types.hpp"
 #include "console.hpp"
 #include "utils.hpp"
+#include "pair.hpp"
 
 namespace {
 
@@ -198,9 +199,7 @@ bool filename_equals(char* name, const string& path){
     return true;
 }
 
-} //end of anonymous namespace
-
-vector<disks::file> fat32::ls(dd disk, const disks::partition_descriptor& partition, const vector<string>& path){
+bool cache_disk_partition(fat32::dd disk, const disks::partition_descriptor& partition){
     if(cached_disk != disk.uuid || cached_partition != partition.uuid){
         partition_start = partition.start;
 
@@ -211,11 +210,11 @@ vector<disks::file> fat32::ls(dd disk, const disks::partition_descriptor& partit
         cached_partition = partition.uuid;
     }
 
-    if(!fat_bs || !fat_is){
-        //Something went wrong when reading the two base vectors
-        return {};
-    }
+    //Something may go wrong when reading the two base vectors
+    return fat_bs && fat_is;
+}
 
+pair<bool, unique_heap_array<cluster_entry>> find_cluster(fat32::dd disk, const vector<string>& path){
     auto cluster_addr = cluster_lba(fat_bs->root_directory_cluster_start);
 
     unique_heap_array<cluster_entry> current_cluster(16 * fat_bs->sectors_per_cluster);
@@ -244,7 +243,7 @@ vector<disks::file> fat32::ls(dd disk, const disks::partition_descriptor& partit
 
                             break;
                         } else {
-                            return {};
+                            return make_pair(false, unique_heap_array<cluster_entry>());
                         }
                     }
                 }
@@ -253,31 +252,47 @@ vector<disks::file> fat32::ls(dd disk, const disks::partition_descriptor& partit
             if(!found){
                 //TODO If not end_reached, read the next cluster
 
-                return {};
+                return make_pair(false, unique_heap_array<cluster_entry>());
             }
         }
 
-        return files(current_cluster);
+        return make_pair(true, move(current_cluster));
     }
-
-    return {};
 }
 
+} //end of anonymous namespace
+
 uint64_t fat32::free_size(dd disk, const disks::partition_descriptor& partition){
-    if(cached_disk != disk.uuid || cached_partition != partition.uuid){
-        partition_start = partition.start;
-
-        cache_bs(disk, partition);
-        cache_is(disk, partition);
-
-        cached_disk = disk.uuid;
-        cached_partition = partition.uuid;
-    }
-
-    if(!fat_bs || !fat_is){
-        //Something went wrong when reading the two base vectors
+    if(!cache_disk_partition(disk, partition)){
         return 0;
     }
 
     return fat_is->free_clusters * fat_bs->sectors_per_cluster * 512;
 }
+
+vector<disks::file> fat32::ls(dd disk, const disks::partition_descriptor& partition, const vector<string>& path){
+    if(!cache_disk_partition(disk, partition)){
+        return {};
+    }
+
+    auto cluster = find_cluster(disk, path);
+
+    if(cluster.first){
+        return files(cluster.second);
+    } else {
+        return {};
+    }
+}
+
+string fat32::read_file(dd disk, const disks::partition_descriptor& partition, const vector<string>& path, const string& file){
+    if(!cache_disk_partition(disk, partition)){
+        return "";
+    }
+
+    string content = "";
+
+    auto cluster = find_cluster(disk, path);
+
+
+    return move(content);
+}
diff --git a/kernel/src/shell.cpp b/kernel/src/shell.cpp
index 0688dd0d..98d2adfc 100644
--- a/kernel/src/shell.cpp
+++ b/kernel/src/shell.cpp
@@ -53,13 +53,14 @@ void ls_command(const vector<string>& params);
 void cd_command(const vector<string>& params);
 void pwd_command(const vector<string>& params);
 void free_command(const vector<string>& params);
+void cat_command(const vector<string>& params);
 
 struct command_definition {
     const char* name;
     void (*function)(const vector<string>&);
 };
 
-command_definition commands[18] = {
+command_definition commands[19] = {
     {"reboot", reboot_command},
     {"help", help_command},
     {"uptime", uptime_command},
@@ -78,6 +79,7 @@ command_definition commands[18] = {
     {"cd", cd_command},
     {"pwd", pwd_command},
     {"sysinfo", sysinfo_command},
+    {"cat", cat_command},
 };
 
 string current_input;
@@ -500,6 +502,14 @@ void cd_command(const vector<string>& params){
     }
 }
 
+void cat_command(const vector<string>& params){
+    if(params.size() == 1){
+        k_print_line("No file provided");
+    } else {
+        auto content = disks::read_file(params[1]);
+    }
+}
+
 } //end of anonymous namespace
 
 void init_shell(){