implement subshell, and fix vector operator[] unvalid index

4 files changed, 106 insertions, 23 deletions

diff --git a/src/eval.cc b/src/eval.cc
index 0192ab7..6d16cf7 100644
--- a/src/eval.cc
+++ b/src/eval.cc
@@ -30,7 +30,7 @@ extern char **environ;
 namespace ov4
 {
 
-int eval_exe(string s, bool is_aync)
+int eval_exe(const string &s, bool is_aync)
 {
     loggerln("eval_exe: receive {}", s);
 
@@ -69,10 +69,13 @@ int eval_exe(string s, bool is_aync)
 
         sigprocmask(SIG_SETMASK, &prev, nullptr);
 
-        // program inside execve may use SIGTTIN/SIGTTOU so just restore in child
+        // program inside execve may use SIGTTIN/SIGTTOU
+        // so just restore in child
         sigprocmask(SIG_UNBLOCK, &block_io, nullptr);
         execve(cmd_c, argv, environ);
 
+        // execve: if success, never returns
+
         wrap_eliminator(cmdline);
         cout << cmdline << flush;
         switch (errno)
@@ -135,12 +138,85 @@ int eval_exe(string s, bool is_aync)
     return 0;
 }
 
-int eval_tree_cd(size_t i, const T_lexer &lexer_instance)
+int eval_subshell(size_t i, const T_lexer &lexer_instance)
+{
+    println("eval_tree_cd: processing subshell");
+
+    // TODO: implement async
+    bool is_aync = false;
+
+    char cmdline[] = "subshell";
+
+    // block_io signals can stop shell
+    // when child is at foreground, parent shell is at background
+    sigprocmask(SIG_BLOCK, &block_io, nullptr);
+
+    sigset_t prev;
+    block_all(&prev);
+
+    shell_pgid = getpgid(0);
+    pid_t pid = fork();
+    
+    if (pid == 0) // child
+    {
+        setpgid(0, 0);
+        if (!is_aync) // foreground
+            tcsetpgrp(tty_fd, getpgrp());
+
+        sigprocmask(SIG_SETMASK, &prev, nullptr);
+
+        // program inside execve may use SIGTTIN/SIGTTOU
+        // so just restore in child
+        sigprocmask(SIG_UNBLOCK, &block_io, nullptr);
+        eval_tree_cd(i, lexer_instance, true);
+        exit(0);
+    }
+
+    // parent
+
+    exit_required_pid = pid;
+
+    if (!is_aync)  // foreground
+    {   
+        addjob(pid, FG, cmdline); 
+        sigset_t prev_with_sigchld_blocked = prev;
+        sigaddset(&prev_with_sigchld_blocked, SIGCHLD);
+        sigprocmask(SIG_SETMASK, &prev_with_sigchld_blocked, NULL);
+        waitfg(pid);
+        sigprocmask(SIG_SETMASK, &prev, NULL);
+
+        return exit_code;
+    }
+    else // background
+    {
+        addjob(pid, BG, cmdline);
+        sigprocmask(SIG_SETMASK, &prev, NULL);
+        cout << "[" << pid2jid(pid) << "] (" << pid << ") " << cmdline;
+
+        // POSIX:
+        // async command returns 0 immediately
+        // TODO: recurring async 
+        return 0;
+    }
+}
+
+int eval_tree_cd(size_t i, const T_lexer &lexer_instance, bool inside_subshell)
 {
     // TODO: async
 
     int ret = -1;
 
+    println("eval_tree_cd: processing {} subshell {}", i, (lexer_instance.ast[i].subshell ? "TRUE" : "FALSE"));
+
+    // if it's a subshell, and current AST's subshell status is not subshell
+    // (subshell should be forkerd already, then set inside_subshell = true)
+    // fork itself
+    if (lexer_instance.ast[i].subshell && !inside_subshell)
+    {
+        eval_subshell(i, lexer_instance);
+        return 0;
+    }
+
     if (lexer_instance.ast[i].token_type == TEXT)
     {
         ret = eval_exe(lexer_instance.ast[i].command_text, false);
@@ -149,7 +225,7 @@ int eval_tree_cd(size_t i, const T_lexer &lexer_instance)
 
     if (lexer_instance.ast[i].left != string::npos)
     {
-        ret = eval_tree_cd(lexer_instance.ast[i].left, lexer_instance);
+        ret = eval_tree_cd(lexer_instance.ast[i].left, lexer_instance, false);
     }
 
     if (lexer_instance.ast[i].right != string::npos)
@@ -157,7 +233,7 @@ int eval_tree_cd(size_t i, const T_lexer &lexer_instance)
         if (lexer_instance.ast[i].token_type == LOGIC_AND && ret != 0) return ret;
         if (lexer_instance.ast[i].token_type == LOGIC_OR && ret == 0) return ret;
         
-        ret = eval_tree_cd(lexer_instance.ast[i].right, lexer_instance);
+        ret = eval_tree_cd(lexer_instance.ast[i].right, lexer_instance, false);
     }
     return ret;
 }
@@ -190,7 +266,7 @@ void eval(char *cmdline)
         return;
     }
 
-    eval_tree_cd(0, lexer_instance);
+    eval_tree_cd(0, lexer_instance, false);
     return;
 }
 
diff --git a/src/lexer/ast.cc b/src/lexer/ast.cc
index 292728b..da96c6f 100644
--- a/src/lexer/ast.cc
+++ b/src/lexer/ast.cc
@@ -65,10 +65,11 @@ void T_lexer::parse(size_t cmd_begin, size_t cmd_end, size_t ast_vec)
 
     // if it's fully inside bracket
     // then it's subshell
-    loggerln("parse: left token type: {}, right: {}", 
-        magic_enum::enum_name(token[cmd_begin].token_type), 
-        magic_enum::enum_name(token[cmd_end-1].token_type));
-    if (token[cmd_begin].token_type == LEFT_BRACKET && token[cmd_end-1].token_type == RIGHT_BRACKET)
+    if (cmd_begin != cmd_end)
+        loggerln("parse: left token type: {}, right: {}", 
+            magic_enum::enum_name(token[cmd_begin].token_type), 
+            magic_enum::enum_name(token[cmd_end-1].token_type));
+    if (cmd_begin != cmd_end && token[cmd_begin].token_type == LEFT_BRACKET && token[cmd_end-1].token_type == RIGHT_BRACKET)
     {
         ast[ast_vec].subshell = true;
         loggerln("parse: detect subshell {}", ast_vec);
diff --git a/src/lexer/token.cc b/src/lexer/token.cc
index 317b456..ab9f263 100644
--- a/src/lexer/token.cc
+++ b/src/lexer/token.cc
@@ -12,6 +12,8 @@
 
 using namespace std; // remove this
 
+constexpr bool TOKEN_DEBUG = false;
+
 namespace ov4
 {
 
@@ -43,7 +45,7 @@ void T_lexer::bracket_depth_changer(char c, int &bracket_depth)
     if (c == '(')
     {
         bracket_depth++;
-        loggerln("changed depth: {}", bracket_depth);
+        if constexpr (TOKEN_DEBUG) loggerln("changed depth: {}", bracket_depth);
         return;
     }
     if (c == ')')
@@ -64,7 +66,7 @@ void T_lexer::bracket_depth_changer(char c, int &bracket_depth)
  */
 bool T_lexer::token_continue(const string &s, char next)
 {
-    loggerln("token_continue: receiving {} {}", s, next);
+    if constexpr (TOKEN_DEBUG) loggerln("token_continue: receiving {} {}", s, next);
     // s is empty, so next can be part of the token
     if (s.size() == 0) return true;
 
@@ -95,7 +97,7 @@ bool T_lexer::token_continue(const string &s, char next)
     }
     else
     {
-        loggerln("symbol not found in map");
+        if constexpr (TOKEN_DEBUG) loggerln("symbol not found in map");
         return false;
     }
 }
@@ -108,16 +110,16 @@ void T_lexer::token_push(const string &push_s, int bracket_depth, bool force_tex
     string trimmed = trim(push_s);
     if (trimmed == "")   return;
 
-    loggerln("finding {} in map", trimmed);
+    if constexpr (TOKEN_DEBUG) loggerln("finding {} in map", trimmed);
 
     if (symbol_property.contains(trimmed) && !force_text) // symbol
     {
-        loggerln("token_push: adding symbol");
+        if constexpr (TOKEN_DEBUG) loggerln("token_push: adding symbol");
         tmp.token_type = symbol_property.at(trimmed).enum_type;
     } 
     else
     {
-        loggerln("token_push: adding text");
+        if constexpr (TOKEN_DEBUG) loggerln("token_push: adding text");
         if (force_text)
             trimmed = trim(trimmed, "\'\"");
         tmp.token_type = TEXT;
@@ -145,32 +147,32 @@ int T_lexer::tokenizer(const string &s)
 
         prev_str += c;
         
-        loggerln("---");
-        loggerln("prev_str .{}. next char {}", prev_str, s[i+1]);
+        if constexpr (TOKEN_DEBUG) loggerln("---");
+        if constexpr (TOKEN_DEBUG) loggerln("prev_str .{}. next char {}", prev_str, s[i+1]);
 
         if (c == '\'' || c == '\"')
         {
-            loggerln("quotation");
+            if constexpr (TOKEN_DEBUG) loggerln("quotation");
 
             // turn on GUARD
             if (guard == GUARD_OFF)
             {
                 guard = (c == '\'') ? GUARD_STRONG : GUARD_WEAK;
-                loggerln("set guard {}", (c == '\'') ? "GUARD_STRONG" : "GUARD_WEAK");
+                if constexpr (TOKEN_DEBUG) loggerln("set guard {}", (c == '\'') ? "GUARD_STRONG" : "GUARD_WEAK");
                 continue;
             }
             // turn off
             else if (guard == GUARD_STRONG && c == '\'')
             {
                 guard = GUARD_OFF;
-                loggerln("quitting strong guard");
+                if constexpr (TOKEN_DEBUG) loggerln("quitting strong guard");
                 force_text = true;
             }
             //turn off
             else if (guard == GUARD_WEAK && c == '\"')
             {
                 guard = GUARD_OFF;
-                loggerln("quitting weak guard");
+                if constexpr (TOKEN_DEBUG) loggerln("quitting weak guard");
                 force_text = true;
             } else
                 continue;
@@ -178,7 +180,7 @@ int T_lexer::tokenizer(const string &s)
         // not quotation mark
         else if ((guard == GUARD_STRONG || guard == GUARD_WEAK))
         {
-            loggerln("tokenizer: guarded, continue");
+            if constexpr (TOKEN_DEBUG) loggerln("tokenizer: guarded, continue");
             continue;
         }
 
diff --git a/src/main.cc b/src/main.cc
index a884f78..088b4ca 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -75,7 +75,11 @@ int main([[maybe_unused]] int argc, [[maybe_unused]] char **argv)
 	    exit(0);
 	}
 
+
 	/* Evaluate the command line */
+    // trim \n
+    if(cmdline[strlen(cmdline)-1] == '\n')
+        cmdline[strlen(cmdline)-1] = '\0';
 	eval(cmdline);
 	fflush(stdout);
 	fflush(stdout);