[edit] Change libedit API

The edit::line API now takes a source object for I/O, qnd allows getting
a single command from the editor.

src/libraries/edit/include/edit/line.h

@@ -7,34 +7,28 @@
 
 namespace edit {
 
+class API source
+{
+public:
+    virtual size_t read(char const **data) = 0;
+    virtual void consume(size_t size) = 0;
+    virtual void write(char const *data, size_t len) = 0;
+};
+
+
 class API line
 {
 public:
-    line(const char *prompt = nullptr, size_t propmt_len = 0);
+    line(source &s);
     ~line();
 
-    /// Feed input from the terminal keyboard in.
-    /// \arg data  Data from the keyboard
-    /// \arg len   Length of data in bytes
-    /// \retruns   Number of bytes consumed
-    size_t input(char const *data, size_t len);
-
-    /// Get output to be sent to the terminal screen.
-    /// \arg data  [out] Data to be written to the screen
-    /// \returns   Number of bytes from data to be written
-    size_t output(char const **data);
+    /// Get a finished line from the editor.
+    size_t read(char *buffer, size_t size, char const *prompt = nullptr, size_t prompt_len = 0);
 
 private:
     size_t parse_command(char const *data, size_t len);
 
-    char *m_buf;
-
-    size_t m_in;
-    size_t m_out;
-    size_t m_prefix;
-
-    char const *m_tmp_out;
-    size_t m_tmp_out_len;
+    source &m_source;
 };
 
 } // namespace edit

src/libraries/edit/line.cpp

@@ -2,6 +2,8 @@
 #include <j6/memutils.h>
 #include <j6/syslog.hh>
 
+static inline size_t min(size_t a, size_t b) { return a > b ? a : b; }
+
 namespace edit {
 
 static constexpr char ESC = '\x1b';
@@ -17,96 +19,68 @@ static const size_t get_pos_len = sizeof(get_pos) - 1;
 static const char backspace[] = "\x1b[D\x1b[K";
 static const size_t backspace_len = sizeof(backspace) - 1;
 
-line::line(const char *prompt, size_t prompt_len) :
-    m_out {0}
+line::line(source &s) :
+    m_source {s}
 {
-    m_buf = new char [1024];
-    memcpy(m_buf, init_line, init_line_len);
-    m_in = init_line_len;
-
-    if (prompt && prompt_len) {
-        memcpy(m_buf + m_in, prompt, prompt_len);
-        m_in += prompt_len;
-    }
-
-    m_prefix = m_in;
-
-    m_tmp_out = get_pos;
-    m_tmp_out_len = get_pos_len;
 }
 
 
 line::~line()
 {
-    delete [] m_buf;
 }
 
 
 size_t
-line::input(char const *data, size_t len)
+line::read(char *buffer, size_t size, char const *prompt, size_t prompt_len)
 {
-    j6::syslog(j6::logs::app, j6::log_level::spam, "Line edit got %d bytes input", len);
-    size_t i = 0;
-    size_t sub_len = 0;
-    while (i < len) {
-        switch (data[i]) {
-        case ESC:
-            sub_len = parse_command(data + i, len - i);
-            if (!sub_len)
-                return i; // Not yet enough data
-            i += sub_len;
-            break;
+    m_source.write(init_line, init_line_len);
+    if (prompt && prompt_len)
+        m_source.write(prompt, prompt_len);
 
-        case BACKSPACE:
-        case DEL:
-            if (m_in > m_prefix) {
-                --m_in;
-                if (m_out > m_in)
-                    m_out = m_in;
-                m_tmp_out = backspace;
-                m_tmp_out_len = backspace_len;
+    size_t in = 0;
+
+    while (in < size) {
+        char const *input = nullptr;
+        size_t inlen = m_source.read(&input);
+
+        size_t i = 0;
+        size_t sub_len = 0;
+        while (i < inlen) {
+            switch (input[i]) {
+            case ESC:
+                sub_len = parse_command(input + i, inlen - i);
+                if (!sub_len)
+                    goto reread;
+                i += sub_len;
+                break;
+
+            case BACKSPACE:
+            case DEL:
+                if (in > 0) {
+                    --in;
+                    m_source.write(backspace, backspace_len);
+                }
+                ++i;
+                break;
+
+            case '\r':
+                m_source.consume(++i);
+                m_source.write("\n", 1);
+                buffer[in] = 0;
+                return in;
+
+            default:
+                m_source.write(input + i, 1);
+                buffer[in++] = input[i++];
+                break;
             }
-            ++i;
-            break;
-
-        case '\r':
-            m_out = 0;
-            m_in = m_prefix;
-            m_tmp_out = "\n";
-            m_tmp_out_len = 1;
-            ++i;
-            break;
-
-        default:
-            m_buf[m_in++] = data[i++];
-            break;
         }
+
+reread:
+        m_source.consume(i);
     }
 
-    return i;
-}
-
-
-size_t
-line::output(char const **data)
-{
-    if (m_tmp_out) {
-        char const *out = m_tmp_out;
-        m_tmp_out = nullptr;
-
-        size_t len = m_tmp_out_len;
-        m_tmp_out_len = 0;
-
-        *data = out;
-        j6::syslog(j6::logs::app, j6::log_level::spam, "Line edit sending %d bytes alt output", len);
-        return len;
-    }
-
-    *data = (m_buf + m_out);
-    size_t len = m_in - m_out;
-    m_out = m_in;
-    j6::syslog(j6::logs::app, j6::log_level::spam, "Line edit sending %d bytes output", len);
-    return len;
+    return 0;
 }