Merge remote-tracking branch 'lenormf/readonly-mode'

5 files changed, 46 insertions, 16 deletions

diff --git a/src/buffer.cc b/src/buffer.cc
index df9a7613..51be811f 100644
--- a/src/buffer.cc
+++ b/src/buffer.cc
@@ -606,6 +606,13 @@ void Buffer::set_fs_timestamp(timespec ts)
 
 void Buffer::on_option_changed(const Option& option)
 {
+    if (option.name() == "readonly")
+    {
+        if (option.get<bool>())
+            m_flags |= Flags::ReadOnly;
+        else
+            m_flags &= ~Flags::ReadOnly;
+    }
     run_hook_in_own_context("BufSetOption",
                             format("{}={}", option.name(), option.get_as_string()));
 }
diff --git a/src/buffer.hh b/src/buffer.hh
index 98806296..e84c14e0 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -101,12 +101,13 @@ class Buffer : public SafeCountable, public OptionManagerWatcher, public Scope
 public:
     enum class Flags
     {
-        None = 0,
-        File   = 1 << 0,
-        New    = 1 << 1,
-        Fifo   = 1 << 2,
-        NoUndo = 1 << 3,
-        Debug  = 1 << 4
+        None     = 0,
+        File     = 1 << 0,
+        New      = 1 << 1,
+        Fifo     = 1 << 2,
+        NoUndo   = 1 << 3,
+        Debug    = 1 << 4,
+        ReadOnly = 1 << 5,
     };
 
     Buffer(String name, Flags flags, StringView data = {},
diff --git a/src/buffer_manager.cc b/src/buffer_manager.cc
index 98dfc7f1..79546d53 100644
--- a/src/buffer_manager.cc
+++ b/src/buffer_manager.cc
@@ -87,7 +87,8 @@ void BufferManager::backup_modified_buffers()
 {
     for (auto& buf : m_buffers)
     {
-        if ((buf->flags() & Buffer::Flags::File) and buf->is_modified())
+        if ((buf->flags() & Buffer::Flags::File) and buf->is_modified()
+            and not (buf->flags() & Buffer::Flags::ReadOnly))
             write_buffer_to_backup_file(*buf);
     }
 }
diff --git a/src/commands.cc b/src/commands.cc
index 0a13938e..fa61a8c4 100644
--- a/src/commands.cc
+++ b/src/commands.cc
@@ -239,6 +239,12 @@ void write_buffer(const ParametersParser& parser, Context& context, const ShellC
     if (parser.positional_count() == 0 and !(buffer.flags() & Buffer::Flags::File))
         throw runtime_error("cannot write a non file buffer without a filename");
 
+    // if the buffer is in read-only mode and we try to save it directly
+    // or we try to write to it indirectly using e.g. a symlink, throw an error
+    if ((context.buffer().flags() & Buffer::Flags::ReadOnly)
+        and (parser.positional_count() == 0 or real_path(parser[0]) == buffer.name()))
+        throw runtime_error("cannot overwrite the buffer when in readonly mode");
+
     auto filename = parser.positional_count() == 0 ?
                         buffer.name() : parse_filename(parser[0]);
     write_buffer_to_file(buffer, filename);
@@ -260,7 +266,8 @@ void write_all_buffers()
 {
     for (auto& buffer : BufferManager::instance())
     {
-        if ((buffer->flags() & Buffer::Flags::File) and buffer->is_modified())
+        if ((buffer->flags() & Buffer::Flags::File) and buffer->is_modified()
+            and !(buffer->flags() & Buffer::Flags::ReadOnly))
             write_buffer_to_file(*buffer, buffer->name());
     }
 }
diff --git a/src/main.cc b/src/main.cc
index 2ebeb632..2a72d423 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -265,6 +265,7 @@ void register_options()
     reg.declare_option("modelinefmt", "format string used to generate the modeline",
                        "%val{bufname} %val{cursor_line}:%val{cursor_char_column} "_str);
     reg.declare_option("debug", "various debug flags", DebugFlags::None);
+    reg.declare_option("readonly", "prevent buffers from being modified", false);
 }
 
 struct convert_to_client_mode
@@ -460,7 +461,7 @@ int run_client(StringView session, StringView init_command, UIType ui_type)
 }
 
 int run_server(StringView session, StringView init_command,
-               bool ignore_kakrc, bool daemon, UIType ui_type,
+               bool ignore_kakrc, bool daemon, bool readonly, UIType ui_type,
                ConstArrayView<StringView> files, ByteCoord target_coord)
 {
     static bool terminate = false;
@@ -503,6 +504,8 @@ int run_server(StringView session, StringView init_command,
 
     write_to_debug_buffer("*** This is the debug buffer, where debug info will be written ***");
 
+    GlobalScope::instance().options().get_local_option("readonly").set(readonly);
+
     Server server(session.empty() ? to_string(getpid()) : session.str());
 
     bool startup_error = false;
@@ -536,7 +539,9 @@ int run_server(StringView session, StringView init_command,
         {
             try
             {
-                open_or_create_file_buffer(file);
+                Buffer *buffer = open_or_create_file_buffer(file);
+                if (readonly)
+                    buffer->flags() |= Buffer::Flags::ReadOnly;
             }
             catch (Kakoune::runtime_error& error)
             {
@@ -741,7 +746,8 @@ int main(int argc, char* argv[])
                    { "q", { false, "in filter mode, be quiet about errors applying keys" } },
                    { "ui", { true, "set the type of user interface to use (ncurses, dummy, or json)" } },
                    { "l", { false, "list existing sessions" } },
-                   { "clear", { false, "clear dead sessions" } } }
+                   { "clear", { false, "clear dead sessions" } },
+                   { "ro", { false, "readonly mode" } } }
     };
     try
     {
@@ -773,11 +779,11 @@ int main(int argc, char* argv[])
 
         if (auto session = parser.get_switch("p"))
         {
-            for (auto opt : { "c", "n", "s", "d", "e" })
+            for (auto opt : { "c", "n", "s", "d", "e", "ro" })
             {
                 if (parser.get_switch(opt))
                 {
-                    write_stderr(format("error: -{} makes not sense with -p\n", opt));
+                    write_stderr(format("error: -{} is incompatible with -p\n", opt));
                     return -1;
                 }
             }
@@ -789,20 +795,27 @@ int main(int argc, char* argv[])
 
         if (auto keys = parser.get_switch("f"))
         {
+            if (parser.get_switch("ro"))
+            {
+                write_stderr("error: -ro is incompatible with -f\n");
+                return -1;
+            }
+
             Vector<StringView> files;
             for (size_t i = 0; i < parser.positional_count(); ++i)
                 files.emplace_back(parser[i]);
 
-            return run_filter(*keys, init_command, files, (bool)parser.get_switch("q"));
+            return run_filter(*keys, init_command, files,
+                              (bool)parser.get_switch("q"));
         }
 
         if (auto server_session = parser.get_switch("c"))
         {
-            for (auto opt : { "n", "s", "d" })
+            for (auto opt : { "n", "s", "d", "ro" })
             {
                 if (parser.get_switch(opt))
                 {
-                    write_stderr(format("error: -{} makes not sense with -c\n", opt));
+                    write_stderr(format("error: -{} is incompatible with -c\n", opt));
                     return -1;
                 }
             }
@@ -840,6 +853,7 @@ int main(int argc, char* argv[])
                 return run_server(session, init_command,
                                   (bool)parser.get_switch("n"),
                                   (bool)parser.get_switch("d"),
+                                  (bool)parser.get_switch("ro"),
                                   ui_type, files, target_coord);
             }
             catch (convert_to_client_mode& convert)