Shell: Add unalias builtin

Add shell unalias builtin to remove aliases

3 files changed, 57 insertions, 3 deletions

diff --git a/Userland/Shell/Builtin.cpp b/Userland/Shell/Builtin.cpp
index 617adb9498..bb290e7962 100644
--- a/Userland/Shell/Builtin.cpp
+++ b/Userland/Shell/Builtin.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2020-2021, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -67,6 +67,45 @@ int Shell::builtin_alias(int argc, const char** argv)
     return fail ? 1 : 0;
 }
 
+int Shell::builtin_unalias(int argc, const char** argv)
+{
+    bool remove_all { false };
+    Vector<const char*> arguments;
+
+    Core::ArgsParser parser;
+    parser.set_general_help("Remove alias from the list of aliases");
+    parser.add_option(remove_all, "Remove all aliases", nullptr, 'a');
+    parser.add_positional_argument(arguments, "List of aliases to remove", "alias", Core::ArgsParser::Required::No);
+
+    if (!parser.parse(argc, const_cast<char**>(argv), Core::ArgsParser::FailureBehavior::PrintUsage))
+        return 1;
+
+    if (remove_all) {
+        m_aliases.clear();
+        cache_path();
+        return 0;
+    }
+
+    if (arguments.is_empty()) {
+        warnln("unalias: not enough arguments");
+        parser.print_usage(stderr, argv[0]);
+        return 1;
+    }
+
+    bool failed { false };
+    for (auto& argument : arguments) {
+        if (!m_aliases.contains(argument)) {
+            warnln("unalias: {}: alias not found", argument);
+            failed = true;
+            continue;
+        }
+        m_aliases.remove(argument);
+        remove_entry_from_cache(argument);
+    }
+
+    return failed ? 1 : 0;
+}
+
 int Shell::builtin_bg(int argc, const char** argv)
 {
     int job_id = -1;
diff --git a/Userland/Shell/Shell.cpp b/Userland/Shell/Shell.cpp
index 6f247d6485..487851f0cf 100644
--- a/Userland/Shell/Shell.cpp
+++ b/Userland/Shell/Shell.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2020-2021, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -1362,6 +1362,19 @@ void Shell::add_entry_to_cache(const String& entry)
     cached_path.insert(index, entry);
 }
 
+void Shell::remove_entry_from_cache(const String& entry)
+{
+    size_t index { 0 };
+    auto match = binary_search(
+        cached_path.span(),
+        entry,
+        &index,
+        [](const auto& a, const auto& b) { return strcmp(a.characters(), b.characters()); });
+
+    if (match)
+        cached_path.remove(index);
+}
+
 void Shell::highlight(Line::Editor& editor) const
 {
     auto line = editor.line();
diff --git a/Userland/Shell/Shell.h b/Userland/Shell/Shell.h
index 0a90751fcc..3dbb0201f0 100644
--- a/Userland/Shell/Shell.h
+++ b/Userland/Shell/Shell.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2020-2021, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -30,6 +30,7 @@
     __ENUMERATE_SHELL_BUILTIN(exit)    \
     __ENUMERATE_SHELL_BUILTIN(export)  \
     __ENUMERATE_SHELL_BUILTIN(glob)    \
+    __ENUMERATE_SHELL_BUILTIN(unalias) \
     __ENUMERATE_SHELL_BUILTIN(unset)   \
     __ENUMERATE_SHELL_BUILTIN(history) \
     __ENUMERATE_SHELL_BUILTIN(umask)   \
@@ -287,6 +288,7 @@ private:
     Optional<int> resolve_job_spec(const String&);
     void cache_path();
     void add_entry_to_cache(const String&);
+    void remove_entry_from_cache(const String&);
     void stop_all_jobs();
     const Job* m_current_job { nullptr };
     LocalFrame* find_frame_containing_local_variable(const String& name);