From 1e20276520eb70051fc4bf29f0bbd196b66cca53 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Vin=C3=ADcius=20R=2E=20Miguel?= <lemao.vrm07@hotmail.com>
Date: Thu, 4 Jun 2020 01:17:10 -0300
Subject: [PATCH] Piped commands (almost) working

---
 Headers/input.h   |  4 +++
 Headers/opsys.h   |  6 +++-
 Sources/input.cpp | 20 ++++++++++---
 Sources/main.cpp  |  1 +
 Sources/opsys.cpp | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 5 files changed, 109 insertions(+), 7 deletions(-)

diff --git a/Headers/input.h b/Headers/input.h
index 2f7c5e8..1d117e1 100644
--- a/Headers/input.h
+++ b/Headers/input.h
@@ -10,6 +10,10 @@ using std::vector;
 #define RED_ANSI   "\x1b[31m" // ANSI escape code for red
 #define BLUE_ANSI  "\x1b[34m" // ANSI escape code for blue
 #define RESET_ANSI "\x1b[0m"  // ANSI escape code to reset stdout's color
+#define KEY_UP    72          // ASCII code for arrow key up
+#define KEY_LEFT  75          // ASCII code for arrow key left
+#define KEY_RIGHT 77          // ASCII code for arrow key right
+#define KEY_DOWN  80          // ASCII code for arrow key down
 
 extern bool is_verbose;
 extern bool cwd_changed;
diff --git a/Headers/opsys.h b/Headers/opsys.h
index 24ecfd8..94c49ff 100644
--- a/Headers/opsys.h
+++ b/Headers/opsys.h
@@ -6,6 +6,9 @@
 #include <iostream>         // std::cin, std::cout, printf, fprintf
 extern bool exit_program;
 
+#define WRITE_END 1
+#define READ_END  0
+
 /*!
  * \class SignalHandler
  * \brief Handles SIGHUP and SIGINT signals.
@@ -29,7 +32,8 @@ public:
     string cwd;             // Current working directory
     OpSys();
     void change_dir(vector<string>);
-    short int simple_command(vector<string>);
+    short simple_command(vector<string>);
+    short piped_command (vector<string>, int);
 };
 
 extern OpSys OS;
diff --git a/Sources/input.cpp b/Sources/input.cpp
index 9ede9b6..17a91c6 100644
--- a/Sources/input.cpp
+++ b/Sources/input.cpp
@@ -1,5 +1,6 @@
 #include "Headers/opsys.h"
 #include <regex>            // std::regex and std::regex_replace
+#include <termios.h>
 
 bool is_verbose  = false;
 bool cwd_changed = false;
@@ -49,7 +50,12 @@ void Prompt::get_last_dir()
 
 Prompt::Prompt()
 {
-    get_last_dir();
+//    struct termios t;
+//    tcgetattr(STDIN_FILENO, &t);
+//    t.c_lflag &= ~ICANON;
+//    tcsetattr(STDIN_FILENO, TCSANOW, &t); // WIP for arrow keys support
+
+    get_last_dir();  // Process cwd for exibition on prompt
 }
 
 void Prompt::print()
@@ -80,6 +86,13 @@ void Prompt::parse(string input)
 
 short int Prompt::run()
 {
+    string pipe = "|";
+    int pipe_count = std::count(tokens.begin(), tokens.end(), pipe);
+
+    if(pipe_count)
+    {       // Checks if there's any pipe in the given command
+        OS.piped_command(tokens, pipe_count);
+    }
     if(!tokens[0].compare("cd"))
     {
         OS.change_dir(tokens);
@@ -94,13 +107,12 @@ short int Prompt::run()
         return 1;
     } else if (!tokens[0].compare("quit"))
     {
-        cout << "Exiting" << std::endl;
+        std::cerr << "Exiting.\n";
         exit_program = true;
         return 1;
     }
     else
     {
-        OS.simple_command(tokens);
-        return 1;
+        return OS.simple_command(tokens);
     }
 }
diff --git a/Sources/main.cpp b/Sources/main.cpp
index a11c06d..ff920cb 100644
--- a/Sources/main.cpp
+++ b/Sources/main.cpp
@@ -15,6 +15,7 @@ int main(int argc, char ** argv)
         string line;
         prompt.print();
         std::getline(cin, line);
+
         if (exit_program) return 0; // Tests for "quit"
         if (cin.eof())
         {
diff --git a/Sources/opsys.cpp b/Sources/opsys.cpp
index 71651b9..5ef2f43 100644
--- a/Sources/opsys.cpp
+++ b/Sources/opsys.cpp
@@ -80,6 +80,88 @@ vector<const char*> make_argv(vector<string>const& in)
     return out;
 }
 
+short OpSys::piped_command(vector<string> tokens, int pipe_count)
+{
+    cerr << "I'm in piped_command\n";
+    int n_commands = pipe_count + 1;
+    int file_descriptor_array[10][2];
+    unsigned short i, j=0;
+    string pipe_str = "|";
+
+    cerr << "tokens: [";
+    for(unsigned short int k = 0; k < tokens.size()-1; k++)
+        cerr << "\"" << tokens[k] << "\", ";
+    cerr << "\"" << tokens.back() << "\"]\n";
+
+    for(i=0; i < n_commands; i++)
+    {
+        if (n_commands > 10)
+        {
+            cerr << "More pipes than supported.\n";
+            return -1;
+        }
+        vector<string> aux_cmd;
+        for(;j<tokens.size();)
+        {
+            if (!tokens[j].compare(pipe_str))
+            {
+                j++;
+                cerr << "BREAKING\n";
+                break;
+            }
+            else
+            {
+                aux_cmd.push_back(tokens[j++]);
+                cerr << "aux_cmd: [";
+                for(unsigned short int k = 0; k < aux_cmd.size()-1; k++)
+                    cerr << "\"" << aux_cmd[k] << "\", ";
+                cerr << "\"" << aux_cmd.back() << "\"]\n";
+            }
+        }
+
+            // Creating pipe
+        if(i!=n_commands-1)
+        {
+              if(pipe(file_descriptor_array[i])<0)
+              {
+                  cerr << "Error on pipe initialization.\n";
+                  return -1;
+              }
+        }
+            // Forking
+        pid_t pid = fork();
+        if(pid==0) // Primeiro processo filho
+        {
+            if(i!=n_commands-1)
+            {
+                dup2(file_descriptor_array[i][WRITE_END],STDOUT_FILENO);
+                close(file_descriptor_array[i][READ_END]);
+                close(file_descriptor_array[i][WRITE_END]);
+            }
+            if(i!=0)
+            {
+                dup2(file_descriptor_array[i-1][READ_END],STDIN_FILENO);
+                close(file_descriptor_array[i-1][WRITE_END]);
+                close(file_descriptor_array[i-1][READ_END]);
+            }
+            execvp(aux_cmd[0].c_str(), const_cast<char* const *>(make_argv(aux_cmd).data()));
+            cerr << aux_cmd[0] << ": Comando não encontrado.\n";
+            return -1;
+        }
+        else
+        {
+            if(i!=0)
+            {
+                close(file_descriptor_array[i - 1][READ_END]);
+                close(file_descriptor_array[i - 1][WRITE_END]);
+            }
+        }
+    }
+    for(i=0; i<n_commands; i++)
+          wait(NULL);
+    return 1;
+}
+
 short OpSys::simple_command(vector<string> tokens)
 {
     int status;
@@ -92,13 +174,12 @@ short OpSys::simple_command(vector<string> tokens)
         cerr << "\");\n";
     }
 
-
     pid_t pid = fork();
     if (pid == 0)
     {
         execvp(tokens[0].c_str(), const_cast<char* const *>(make_argv(tokens).data()));
         cerr << tokens[0] << ": command not found.\n";
-        return 0;        // TODO: exit with cleanup
+        return -1;        // TODO: exit with cleanup
     }
     else if (pid < 0)
     {
-- 
2.11.4.GIT