Refactor commands handling and parsing in a CommandManager class

src/command_manager.cc

@@ -0,0 +1,60 @@
+#include "command_manager.hh"
+
+#include "utils.hh"
+#include <algorithm>
+
+namespace Kakoune
+{
+
+void CommandManager::register_command(const std::string& command_name, Command command)
+{
+    m_commands[command_name] = command;
+}
+
+void CommandManager::register_command(const std::vector<std::string>& command_names, Command command)
+{
+    for (auto command_name : command_names)
+        register_command(command_name, command);
+}
+
+static std::vector<std::string> split(const std::string& line)
+{
+    std::vector<std::string> result;
+
+    size_t pos = 0;
+    while (pos != line.length())
+    {
+        while(line[pos] == ' ' and pos != line.length())
+            ++pos;
+
+        size_t token_start = pos;
+
+        while((line[pos] != ' ' or line[pos-1] == '\\') and pos != line.length())
+            ++pos;
+
+        result.push_back(line.substr(token_start, pos - token_start));
+    }
+    return result;
+}
+
+struct command_not_found : public std::runtime_error
+{
+    command_not_found(const std::string& what)
+        : std::runtime_error("command not found: " + what) {}
+};
+
+void CommandManager::execute(const std::string& command_line)
+{
+    std::vector<std::string> tokens = split(command_line);
+    if (tokens.empty())
+        return;
+
+    auto command_it = m_commands.find(tokens[0]);
+    if (command_it == m_commands.end())
+        throw command_not_found(tokens[0]);
+
+    CommandParameters params(tokens.begin() + 1, tokens.end());
+    command_it->second(params);
+}
+
+}

src/command_manager.hh

@@ -0,0 +1,37 @@
+#ifndef command_manager_hh_INCLUDED
+#define command_manager_hh_INCLUDED
+
+#include <string>
+#include <vector>
+#include <unordered_map>
+#include <stdexcept>
+#include <functional>
+
+
+namespace Kakoune
+{
+
+struct wrong_argument_count : public std::runtime_error
+{
+    wrong_argument_count()
+        : std::runtime_error("wrong argument count") {}
+};
+
+typedef std::vector<std::string> CommandParameters;
+typedef std::function<void (const CommandParameters&)> Command;
+
+class CommandManager
+{
+public:
+    void execute(const std::string& command_line);
+
+    void register_command(const std::string& command_name, Command command);
+    void register_command(const std::vector<std::string>& command_names, Command command);
+
+private:
+    std::unordered_map<std::string, Command> m_commands;
+};
+
+}
+
+#endif // command_manager_hh_INCLUDED

src/main.cc

@@ -3,6 +3,7 @@
 #include "buffer.hh"
 #include "file.hh"
 #include "regex_selector.hh"
+#include "command_manager.hh"
 
 #include <unordered_map>
 #include <cassert>
@@ -153,8 +154,12 @@ void do_insert(Window& window)
 
 std::shared_ptr<Window> current_window;
 
-void edit(const std::string& filename)
+void edit(const CommandParameters& params)
 {
+    if (params.size() != 1)
+        throw wrong_argument_count();
+
+    std::string filename = params[0];
     try
     {
         std::shared_ptr<Buffer> buffer(create_buffer_from_file(filename));
@@ -163,68 +168,45 @@ void edit(const std::string& filename)
     }
     catch (file_not_found& what)
     {
+        print_status("new file " + filename);
         current_window = std::make_shared<Window>(std::make_shared<Buffer>(filename));
     }
-    catch (open_file_error& what)
-    {
-        print_status("error opening '" + filename + "' (" + what.what() + ")");
-    }
 }
 
-void write_buffer(const std::string& filename)
+void write_buffer(const CommandParameters& params)
 {
-    try
-    {
-        Buffer& buffer = *current_window->buffer();
-        write_buffer_to_file(buffer,
-                             filename.empty() ? buffer.name() : filename);
-    }
-    catch(open_file_error& what)
-    {
-        print_status("error opening " + filename + "(" + what.what() + ")");
-    }
-    catch(write_file_error& what)
-    {
-        print_status("error writing " + filename + "(" + what.what() + ")");
-    }
+    if (params.size() > 1)
+        throw wrong_argument_count();
+
+    Buffer& buffer = *current_window->buffer();
+    std::string filename = params.empty() ? buffer.name() : params[0];
+
+    write_buffer_to_file(buffer, filename);
 }
 
 bool quit_requested = false;
 
-void quit(const std::string&)
+void quit(const CommandParameters& params)
 {
+    if (params.size() != 0)
+        throw wrong_argument_count();
+
     quit_requested = true;
 }
 
-std::unordered_map<std::string, std::function<void (const std::string& param)>> cmdmap =
-{
-    { "e", edit },
-    { "edit", edit },
-    { "q", quit },
-    { "quit", quit },
-    { "w", write_buffer },
-    { "write", write_buffer },
-};
+CommandManager command_manager;
 
 void do_command()
 {
     try
     {
-        std::string cmd = prompt(":");
-
-        size_t cmd_end = cmd.find_first_of(' ');
-        std::string cmd_name = cmd.substr(0, cmd_end);
-        size_t param_start = cmd.find_first_not_of(' ', cmd_end);
-        std::string param;
-        if (param_start != std::string::npos)
-            param = cmd.substr(param_start, cmd.length() - param_start);
-
-        if (cmdmap.find(cmd_name) != cmdmap.end())
-            cmdmap[cmd_name](param);
-        else
-            print_status(cmd_name + ": no such command");
+        command_manager.execute(prompt(":"));
     }
     catch (prompt_aborted&) {}
+    catch (std::runtime_error& err)
+    {
+        print_status(err.what());
+    }
 }
 
 bool is_blank(char c)
@@ -304,6 +286,10 @@ int main()
 {
     init_ncurses();
 
+    command_manager.register_command(std::vector<std::string>{ "e", "edit" }, edit);
+    command_manager.register_command(std::vector<std::string>{ "q", "quit" }, quit);
+    command_manager.register_command(std::vector<std::string>{ "w", "write" }, write_buffer);
+
     try
     {
         auto buffer = std::make_shared<Buffer>("<scratch>");