From 2714bba3f00d92c4e7ba400c35bd54df19817571 Mon Sep 17 00:00:00 2001
From: AnotherTest <ali.mpfard@gmail.com>
Date: Mon, 8 Jun 2020 11:38:37 +0430
Subject: [PATCH] Shell: Highlight redirections

---
 Shell/Parser.cpp | 32 ++++++++++++++++++++++++++------
 Shell/Parser.h   |  1 +
 Shell/Shell.cpp  | 19 +++++++++++++++++++
 3 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/Shell/Parser.cpp b/Shell/Parser.cpp
index fad6d5e9a58..41bccbfe91e 100644
--- a/Shell/Parser.cpp
+++ b/Shell/Parser.cpp
@@ -147,6 +147,8 @@ Vector<Command> Parser::parse()
             if (ch == '>') {
                 commit_token(Token::Special);
                 begin_redirect_write(STDOUT_FILENO);
+                ASSERT(!m_redirections.is_empty());
+                m_redirections.last().redirection_op_start = m_position;
 
                 // Search for another > for append.
                 push_state(State::InWriteAppendOrRedirectionPath);
@@ -155,6 +157,8 @@ Vector<Command> Parser::parse()
             if (ch == '<') {
                 commit_token(Token::Special);
                 begin_redirect_read(STDIN_FILENO);
+                ASSERT(!m_redirections.is_empty());
+                m_redirections.last().redirection_op_start = m_position;
                 push_state(State::InRedirectionPath);
                 break;
             }
@@ -208,11 +212,15 @@ Vector<Command> Parser::parse()
 
                     if (m_input.characters()[redir_end] == '>') {
                         begin_redirect_write(fd);
+                        ASSERT(!m_redirections.is_empty());
+                        m_redirections.last().redirection_op_start = m_position;
                         // Search for another > for append.
                         push_state(State::InWriteAppendOrRedirectionPath);
                     }
                     if (m_input.characters()[redir_end] == '<') {
                         begin_redirect_read(fd);
+                        ASSERT(!m_redirections.is_empty());
+                        m_redirections.last().redirection_op_start = m_position;
                         push_state(State::InRedirectionPath);
                     }
 
@@ -227,6 +235,8 @@ Vector<Command> Parser::parse()
                     if (next_ch == '>') {
                         commit_token(Token::Special);
                         begin_redirect_write(ch - '0');
+                        ASSERT(!m_redirections.is_empty());
+                        m_redirections.last().redirection_op_start = m_position;
                         ++i;
 
                         // Search for another > for append.
@@ -236,6 +246,8 @@ Vector<Command> Parser::parse()
                     if (next_ch == '<') {
                         commit_token(Token::Special);
                         begin_redirect_read(ch - '0');
+                        ASSERT(!m_redirections.is_empty());
+                        m_redirections.last().redirection_op_start = m_position;
                         ++i;
 
                         push_state(State::InRedirectionPath);
@@ -251,7 +263,7 @@ Vector<Command> Parser::parse()
                 pop_state();
                 push_state(State::InRedirectionPath);
                 ASSERT(m_redirections.size());
-                m_redirections[m_redirections.size() - 1].type = Redirection::FileWriteAppend;
+                m_redirections.last().type = Redirection::FileWriteAppend;
                 break;
             }
 
@@ -263,15 +275,11 @@ Vector<Command> Parser::parse()
             if (ch == '<') {
                 commit_token(Token::Special);
                 begin_redirect_read(STDIN_FILENO);
-                pop_state();
-                push_state(State::InRedirectionPath);
                 break;
             }
             if (ch == '>') {
                 commit_token(Token::Special);
                 begin_redirect_read(STDOUT_FILENO);
-                pop_state();
-                push_state(State::InRedirectionPath);
                 break;
             }
             if (ch == '|') {
@@ -292,8 +300,20 @@ Vector<Command> Parser::parse()
                 push_state(State::InSingleQuotes);
                 break;
             }
-            if (ch == ' ')
+            if (ch == ' ') {
+                if (m_token.is_empty()) {
+                    // foo > bar
+                    //      ^ We are at this space, we want to ignore it but not leave the state.
+                    break;
+                }
+                commit_token(Token::Special);
+                if (m_tokens.is_empty()) {
+                    fprintf(stderr, "Syntax error: Redirection without a path\n");
+                    return {};
+                }
+                pop_state();
                 break;
+            }
             m_token.append(ch);
             break;
         case State::InSingleQuotes:
diff --git a/Shell/Parser.h b/Shell/Parser.h
index e9fcb5f9f49..112747ce3ea 100644
--- a/Shell/Parser.h
+++ b/Shell/Parser.h
@@ -61,6 +61,7 @@ struct Redirection {
     Type type;
     int fd { -1 };
     int rewire_fd { -1 };
+    size_t redirection_op_start { 0 };
     Token path {};
 };
 
diff --git a/Shell/Shell.cpp b/Shell/Shell.cpp
index f1bcf656202..876bf7ea649 100644
--- a/Shell/Shell.cpp
+++ b/Shell/Shell.cpp
@@ -1482,17 +1482,36 @@ void Shell::cache_path()
 void Shell::highlight(Line::Editor& editor) const
 {
     StringBuilder builder;
+    bool is_offset_by_string_start = false;
     if (m_should_continue == ExitCodeOrContinuationRequest::DoubleQuotedString) {
         builder.append('"');
+        is_offset_by_string_start = true;
     }
     if (m_should_continue == ExitCodeOrContinuationRequest::SingleQuotedString) {
         builder.append('\'');
+        is_offset_by_string_start = true;
     }
     builder.append(editor.line());
     auto commands = Parser { builder.string_view() }.parse();
     auto first_command { true };
     for (auto& command : commands) {
         for (auto& subcommand : command.subcommands) {
+            auto& redirections = subcommand.redirections;
+            for (auto& redirection : redirections) {
+                if (redirection.type == Redirection::Pipe)
+                    continue;
+                if (redirection.path.length == 0)
+                    continue;
+                Line::Style redirection_style { Line::Style::Foreground(0x87, 0x9b, 0xcd) }; // 25% darkened periwinkle :)
+                auto end = redirection.path.end;
+                auto redirection_op_start = redirection.redirection_op_start;
+                if (is_offset_by_string_start) {
+                    end--;
+                    redirection_op_start--;
+                }
+
+                editor.stylize({ redirection_op_start, end }, redirection_style);
+            }
             auto first { true };
             for (auto& arg : subcommand.args) {
                 auto start = arg.end - arg.length;