SERVER-4312 consolidate some code into a class/struct

Added new InputBuffer struct to hold the buf, len and pos
variables that were being passed to everything, moved some
code into methods in that struct.  Folded linenoiseRaw into
linenoise.

1 files changed, 98 insertions, 103 deletions

diff --git a/third_party/linenoise/linenoise.cpp b/third_party/linenoise/linenoise.cpp
index 52faa72d98c..e11f77cfd7e 100644
--- a/third_party/linenoise/linenoise.cpp
+++ b/third_party/linenoise/linenoise.cpp
@@ -223,7 +223,6 @@ static string previousSearchText;
 // changing prompt for "(reverse-i-search)`text':" etc.
 //
 struct DynamicPrompt : public PromptBase {
-    PromptInfo& realPrompt;                 // the prompt we are drawing over
     char*       searchText;                 // text we are searching for
     int         searchTextLen;              // chars in searchText
     int         direction;                  // current search direction, 1=forward, -1=reverse
@@ -231,7 +230,7 @@ struct DynamicPrompt : public PromptBase {
     int         reverseSearchBasePromptLen;
     int         endSearchBasePromptLen;
 
-    DynamicPrompt( PromptInfo& pi, int initialDirection ) : realPrompt( pi ), direction( initialDirection ) {
+    DynamicPrompt( PromptInfo& pi, int initialDirection ) : direction( initialDirection ) {
         forwardSearchBasePromptLen = strlen( forwardSearchBasePrompt ); // store constant text lengths
         reverseSearchBasePromptLen = strlen( reverseSearchBasePrompt );
         endSearchBasePromptLen = strlen( endSearchBasePrompt );
@@ -342,6 +341,24 @@ public:
 
 };
 
+struct InputBuffer {
+    char*       buf;
+    int         buflen;
+    int         len;
+    int         pos;
+
+    InputBuffer( char* buffer, int bufferLen ) : buf( buffer ), buflen( bufferLen - 1 ), len( 0 ), pos( 0 ) {
+        buf[0] = 0;
+    }
+
+    int getInputLine( PromptInfo& pi );
+    void refreshLine( PromptBase& pi );
+    int completeLine( PromptInfo& pi );
+    void clearScreen( PromptInfo& pi );
+    int incrementalHistorySearch( PromptInfo& pi, int startChar );
+
+};
+
 // Special codes for keyboard input:
 //
 // Between Windows and the various Linux "terminal" programs, there is some
@@ -393,7 +410,6 @@ static int historyMaxLen = LINENOISE_DEFAULT_HISTORY_MAX_LEN;
 static int historyLen = 0;
 static int historyIndex = 0;
 static char** history = NULL;
-static const char* emptyString = "";
 
 static void linenoiseAtExit( void );
 
@@ -610,11 +626,8 @@ static void dynamicRefresh( PromptBase& pi, char *buf, int len, int pos ) {
 /**
  * Refresh the user's input line: the prompt is already onscreen and is not redrawn here
  * @param pi   PromptInfo struct holding information about the prompt and our screen position
- * @param buf  input buffer to be displayed
- * @param len  count of characters in the buffer
- * @param pos  current cursor position within the buffer (0 <= pos <= len)
  */
-static void refreshLine( PromptBase& pi, const char *buf, int len, int pos ) {
+void InputBuffer::refreshLine( PromptBase& pi ) {
 
     // check for a matching brace/bracket/paren, remember its position if found
     int highlight = -1;
@@ -1104,25 +1117,21 @@ static const char breakChars[] = " =+-/\\*?\"'`&<>;|@{([])}";
  * This routine handles the mechanics of updating the user's input buffer with possible replacement of
  * text as the user selects a proposed completion string, or cancels the completion attempt.
  * @param pi     PromptInfo struct holding information about the prompt and our screen position
- * @param buf    input buffer to be displayed
- * @param buflen size of input buffer in bytes
- * @param len    ptr to count of characters in the buffer (updated)
- * @param pos    ptr to current cursor position within the buffer (0 <= pos <= len) (updated)
  */
-static int completeLine( PromptInfo& pi, char *buf, int buflen, int *len, int *pos ) {
+int InputBuffer::completeLine( PromptInfo& pi ) {
     linenoiseCompletions lc = { 0, NULL };
     char c = 0;
 
     // completionCallback() expects a parsable entity, so find the previous break character and extract
     // a copy to parse.  we also handle the case where tab is hit while not at end-of-line.
-    int startIndex = *pos;
+    int startIndex = pos;
     while ( --startIndex >= 0 ) {
         if ( strchr( breakChars, buf[startIndex] ) ) {
             break;
         }
     }
     ++startIndex;
-    int itemLength = *pos - startIndex;
+    int itemLength = pos - startIndex;
     char* parseItem = reinterpret_cast<char *>( malloc( itemLength + 1 ) );
     int i = 0;
     for ( ; i < itemLength; ++i ) {
@@ -1147,19 +1156,22 @@ static int completeLine( PromptInfo& pi, char *buf, int buflen, int *len, int *p
             /* Show completion or original buffer */
             if ( i < lc.len ) {
                 clen = strlen( lc.cvec[i] );
-                displayLength = *len + clen - itemLength;
+                displayLength = len + clen - itemLength;
                 displayText = reinterpret_cast<char *>( malloc( displayLength + 1 ) );
+                InputBuffer temp( displayText, displayLength + 1 );
+                temp.len = displayLength;
+                temp.pos = startIndex + clen;
                 int j = 0;
                 for ( ; j < startIndex; ++j )
                     displayText[j] = buf[j];
                 strcpy( &displayText[j], lc.cvec[i] );
-                strcpy( &displayText[j+clen], &buf[*pos] );
+                strcpy( &displayText[j+clen], &buf[pos] );
                 displayText[displayLength] = 0;
-                refreshLine( pi, displayText, displayLength, startIndex + clen );
+                temp.refreshLine( pi );
                 free( displayText );
             }
             else {
-                refreshLine( pi, buf, *len, *pos );
+                refreshLine( pi );
             }
 
             do {
@@ -1192,18 +1204,18 @@ static int completeLine( PromptInfo& pi, char *buf, int buflen, int *len, int *p
                     /* Update buffer and return */
                     if ( i < lc.len ) {
                         clen = strlen( lc.cvec[i] );
-                        displayLength = *len + clen - itemLength;
+                        displayLength = len + clen - itemLength;
                         displayText = (char *)malloc( displayLength + 1 );
                         int j = 0;
                         for ( ; j < startIndex; ++j )
                             displayText[j] = buf[j];
                         strcpy( &displayText[j], lc.cvec[i] );
-                        strcpy( &displayText[j+clen], &buf[*pos] );
+                        strcpy( &displayText[j+clen], &buf[pos] );
                         displayText[displayLength] = 0;
                         strcpy( buf, displayText );
                         free( displayText );
-                        *pos = startIndex + clen;
-                        *len = displayLength;
+                        pos = startIndex + clen;
+                        len = displayLength;
                     }
                     stop = true;
                     break;
@@ -1215,7 +1227,7 @@ static int completeLine( PromptInfo& pi, char *buf, int buflen, int *len, int *p
     return c; /* Return last read character */
 }
 
-static void linenoiseClearScreen( PromptInfo& pi, char *buf, int len, int pos ) {
+void InputBuffer::clearScreen( PromptInfo& pi ) {
 
 #ifdef _WIN32
     COORD coord = {0, 0};
@@ -1234,7 +1246,7 @@ static void linenoiseClearScreen( PromptInfo& pi, char *buf, int len, int pos )
         if ( write( 1, "\n", 1 ) == -1 ) return;
 #endif
     pi.promptCursorRowOffset = pi.promptExtraLines;
-    refreshLine( pi, buf, len, pos );
+    refreshLine( pi );
 }
 
 // convert {CTRL + 'A'}, {CTRL + 'a'} and {CTRL + ctrlChar( 'A' )} into ctrlChar( 'A' )
@@ -1261,20 +1273,18 @@ static int cleanupCtrl( int c ) {
  * deletes characters from it, changes direction, and either accepts the found line (for execution or
  * editing) or cancels.
  * @param pi        PromptInfo struct holding information about the (old, static) prompt and our screen position
- * @param buf       input buffer to be displayed
- * @param buflen    size of input buffer in bytes
- * @param len       ptr to count of characters in the buffer (updated)
- * @param pos       ptr to current cursor position within the buffer (0 <= pos <= len) (updated)
  * @param startChar the character that began the search, used to set the initial direction
  */
-int incrementalHistorySearch( PromptInfo& pi, char *buf, int buflen, int *len, int *pos, int startChar ) {
+int InputBuffer::incrementalHistorySearch( PromptInfo& pi, int startChar ) {
 
     // add the current line to the history list so we don't have to special case it
-    history[historyLen - 1] = reinterpret_cast<char *>( realloc( history[historyLen - 1], *len + 1 ) );
+    history[historyLen - 1] = reinterpret_cast<char *>( realloc( history[historyLen - 1], len + 1 ) );
     strcpy( history[historyLen - 1], buf );
-    int historyLineLength = *len;
-    int historyLinePosition = *pos;
-    refreshLine( pi, emptyString, 0, 0 );                        // erase the old input first
+    int historyLineLength = len;
+    int historyLinePosition = pos;
+    char emptyBuffer[1];
+    InputBuffer empty( emptyBuffer, 1 );
+    empty.refreshLine( pi );                        // erase the old input first
     DynamicPrompt dp( pi, ( startChar == ctrlChar( 'R' ) ) ? -1 : 1 );
 
     dp.previousPromptLen = pi.previousPromptLen;
@@ -1454,26 +1464,19 @@ int incrementalHistorySearch( PromptInfo& pi, char *buf, int buflen, int *len, i
     pb.previousPromptLen = dp.promptChars;
     if ( useSearchedLine ) {
         strcpy( buf, history[historyIndex] );
-        *len = historyLineLength;
-        *pos = historyLinePosition;
+        len = historyLineLength;
+        pos = historyLinePosition;
     }
-    dynamicRefresh( pb, buf, *len, *pos );              // redraw the original prompt with current input
-    pi.promptPreviousInputLen = *len;
+    dynamicRefresh( pb, buf, len, pos );              // redraw the original prompt with current input
+    pi.promptPreviousInputLen = len;
     pi.promptCursorRowOffset = pi.promptExtraLines + pb.promptCursorRowOffset;
 
     previousSearchText = dp.searchText;     // save search text for possible reuse on ctrl-R ctrl-R
     return c;                               // pass a character or -1 back to main loop
 }
 
-static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
-    int pos = 0;
-    int len = 0;
-
-    buf[0] = '\0';
-    buflen--; /* Make sure there is always space for the nulterm */
-
-    /* The latest history entry is always our current buffer, that
-     * initially is just an empty string. */
+int InputBuffer::getInputLine( PromptInfo& pi ) {
+    // The latest history entry is always our current buffer
     linenoiseHistoryAdd( "" );
     historyIndex = historyLen - 1;
 
@@ -1511,7 +1514,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             return len;
 
         if ( c == -1 ) {
-            refreshLine( pi, buf, len, pos );
+            refreshLine( pi );
             continue;
         }
 
@@ -1520,7 +1523,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             killRing.lastAction = KillRing::actionOther;
 
             // completeLine does the actual completion and replacement
-            c = completeLine( pi, buf, buflen, &len, &pos );
+            c = completeLine( pi );
 
             if ( c < 0 )                // return on error
                 return len;
@@ -1537,7 +1540,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
         case HOME_KEY:
             killRing.lastAction = KillRing::actionOther;
             pos = 0;
-            refreshLine( pi ,buf, len, pos );
+            refreshLine( pi );
             break;
 
         case ctrlChar( 'B' ):   // ctrl-B, move cursor left by one character
@@ -1545,7 +1548,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             killRing.lastAction = KillRing::actionOther;
             if ( pos > 0 ) {
                 --pos;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1561,7 +1564,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 while ( pos > 0 && isalnum( buf[pos - 1] ) ) {
                     --pos;
                 }
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1572,7 +1575,8 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             free( history[historyLen] );
             // we need one last refresh with the cursor at the end of the line
             // so we don't display the next prompt over the previous input line
-            refreshLine( pi, buf, len, len );  // pass len as pos for EOL
+            pos = len;  // pass len as pos for EOL
+            refreshLine( pi );
             if ( write( 1, "^C", 2 ) == -1 ) return -1;    // Display the ^C we got
             return -1;
 
@@ -1583,7 +1587,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             if ( len > 0 && pos < len ) {
                 memmove( buf + pos, buf + pos + 1, len - pos );
                 --len;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             else if ( len == 0 ) {
                 --historyLen;
@@ -1605,7 +1609,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 killRing.kill( &buf[pos], endingPos - pos, true );
                 memmove( buf + pos, buf + endingPos, len - endingPos + 1 );
                 len -= endingPos - pos;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             killRing.lastAction = KillRing::actionKill;
             break;
@@ -1614,7 +1618,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
         case END_KEY:
             killRing.lastAction = KillRing::actionOther;
             pos = len;
-            refreshLine( pi, buf, len, pos );
+            refreshLine( pi );
             break;
 
         case ctrlChar( 'F' ):   // ctrl-F, move cursor right by one character
@@ -1622,7 +1626,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             killRing.lastAction = KillRing::actionOther;
             if ( pos < len ) {
                 ++pos;
-                refreshLine( pi ,buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1638,7 +1642,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 while ( pos < len && isalnum( buf[pos] ) ) {
                     ++pos;
                 }
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1648,7 +1652,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 memmove( buf + pos - 1, buf + pos, 1 + len - pos );
                 --pos;
                 --len;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1665,7 +1669,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 killRing.kill( &buf[pos], startingPos - pos, false );
                 memmove( buf + pos, buf + startingPos, len - startingPos + 1 );
                 len -= startingPos - pos;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             killRing.lastAction = KillRing::actionKill;
             break;
@@ -1675,7 +1679,8 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             killRing.lastAction = KillRing::actionOther;
             // we need one last refresh with the cursor at the end of the line
             // so we don't display the next prompt over the previous input line
-            refreshLine( pi, buf, len, len );  // pass len as pos for EOL
+            pos = len;    // pass len as pos for EOL
+            refreshLine( pi );
             --historyLen;
             free( history[historyLen] );
             return len;
@@ -1684,12 +1689,12 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             killRing.kill( &buf[pos], len - pos, true );
             buf[pos] = '\0';
             len = pos;
-            refreshLine( pi, buf, len, pos );
+            refreshLine( pi );
             killRing.lastAction = KillRing::actionKill;
             break;
 
         case ctrlChar( 'L' ):   // ctrl-L, clear screen and redisplay line
-            linenoiseClearScreen( pi, buf, len, pos );
+            clearScreen( pi );
             break;
 
         case ctrlChar( 'N' ):   // ctrl-N, recall next line in history
@@ -1718,13 +1723,13 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 strncpy( buf, history[historyIndex], buflen );
                 buf[buflen] = '\0';
                 len = pos = strlen( buf );  // place cursor at end of line
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
         case ctrlChar( 'R' ):   // ctrl-R, reverse history search
         case ctrlChar( 'S' ):   // ctrl-S, forward history search
-            terminatingKeystroke = incrementalHistorySearch( pi, buf, buflen, &len, &pos, c );
+            terminatingKeystroke = incrementalHistorySearch( pi, c );
             break;
 
         case ctrlChar( 'T' ):   // ctrl-T, transpose characters
@@ -1736,7 +1741,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 buf[leftCharPos+1] = aux;
                 if ( pos != len )
                     ++pos;
-                refreshLine( pi ,buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1746,7 +1751,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 len -= pos;
                 memmove( buf, buf + pos, len + 1 );
                 pos = 0;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             killRing.lastAction = KillRing::actionKill;
             break;
@@ -1764,7 +1769,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                 killRing.kill( &buf[pos], startingPos - pos, false );
                 memmove( buf + pos, buf + startingPos, len - startingPos + 1 );
                 len -= startingPos - pos;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             killRing.lastAction = KillRing::actionKill;
             break;
@@ -1778,7 +1783,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                     memmove( buf + pos, restoredText->c_str(), restoredTextLen );
                     pos += restoredTextLen;
                     len += restoredTextLen;
-                    refreshLine( pi, buf, len, pos );
+                    refreshLine( pi );
                     killRing.lastAction = KillRing::actionYank;
                     killRing.lastYankSize = restoredTextLen;
                 }
@@ -1805,7 +1810,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                     pos += restoredTextLen - killRing.lastYankSize;
                     len += restoredTextLen - killRing.lastYankSize;
                     killRing.lastYankSize = restoredTextLen;
-                    refreshLine( pi, buf, len, pos );
+                    refreshLine( pi );
                     break;
                 }
             }
@@ -1818,7 +1823,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             raise( SIGSTOP );                       // Break out in mid-line
             enableRawMode();                        // Back from Linux shell, re-enter raw mode
             if ( write( 1, pi.promptText, pi.promptChars ) == -1 ) break; // Redraw prompt
-            refreshLine( pi, buf, len, pos );   // Refresh the line
+            refreshLine( pi );                      // Refresh the line
             break;
 #endif
 
@@ -1829,7 +1834,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
             if ( len > 0 && pos < len ) {
                 memmove( buf + pos, buf + pos + 1, len - pos );
                 --len;
-                refreshLine( pi, buf, len, pos );
+                refreshLine( pi );
             }
             break;
 
@@ -1858,7 +1863,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                         if ( write( 1, &c, 1) == -1 ) return -1;
                     }
                     else {
-                        refreshLine( pi, buf, len, pos );
+                        refreshLine( pi );
                     }
                 }
                 else {  // not at end of buffer, have to move characters to our right
@@ -1867,7 +1872,7 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
                     ++len;
                     ++pos;
                     buf[len] = '\0';
-                    refreshLine( pi, buf, len, pos );
+                    refreshLine( pi );
                 }
             }
             break;
@@ -1876,49 +1881,39 @@ static int linenoisePrompt( char *buf, int buflen, PromptInfo& pi ) {
     return len;
 }
 
-static int linenoiseRaw( char* buf, int buflen, PromptInfo& pi ) {
+/**
+ * linenoise is a readline replacement.
+ *
+ * call it with a prompt to display and it will return a line of input from the user
+ *
+ * @param prompt text of prompt to display to the user
+ * @return       the returned string belongs to the caller on return and must be freed to prevent memory leaks
+ */
+char* linenoise( const char* prompt ) {
+    char buf[LINENOISE_MAX_LINE];               // buffer for user's input
     int count;
-
-    if ( buflen == 0 ) {
-        errno = EINVAL;
-        return -1;
-    }
-
-    if ( isatty( STDIN_FILENO ) ) {     // input is from a terminal
+    if ( isatty( STDIN_FILENO ) ) {             // input is from a terminal
         if ( enableRawMode() == -1 )
-            return -1;
-        count = linenoisePrompt( buf, buflen, pi );
+            return NULL;
+        PromptInfo pi( prompt, getColumns() );  // struct to hold edited copy of prompt & misc prompt info
+        InputBuffer ib( buf, LINENOISE_MAX_LINE );
+        count = ib.getInputLine( pi );
         disableRawMode();
         printf( "\n" );
+        if ( count == -1 )
+            return NULL;
     }
     else {  // input not from a terminal, we should work with piped input, i.e. redirected stdin
-        if ( fgets( buf, buflen, stdin ) == NULL )
-            return -1;
-        count = strlen( buf );
+        if ( fgets( buf, sizeof buf, stdin ) == NULL )
+            return NULL;
 
         // if fgets() gave us the newline, remove it
+        int count = strlen( buf );
         if ( count && buf[count-1] == '\n' ) {
             --count;
             buf[count] = '\0';
         }
     }
-    return count;
-}
-
-/**
- * linenoise is a readline replacement.
- *
- * call it with a prompt to display and it will return a line of input from the user
- *
- * @param prompt text of prompt to display to the user
- * @return       the returned string belongs to the caller on return and must be freed to prevent memory leaks
- */
-char* linenoise( const char* prompt ) {
-    char buf[LINENOISE_MAX_LINE];               // buffer for user's input
-    PromptInfo pi( prompt, getColumns() );      // struct to hold edited copy of prompt & misc prompt info
-    if ( linenoiseRaw( buf, LINENOISE_MAX_LINE, pi ) == -1 ) {
-        return NULL;
-    }
     return strdup( buf );                       // caller must free buffer
 }