text: /*
   * psql - the PostgreSQL interactive terminal
   *
   * Copyright (c) 2000-2009, PostgreSQL Global Development Group
   *
   * $PostgreSQL: pgsql/src/bin/psql/input.c,v 1.66 2009/01/01 17:23:55 momjian Exp $
   */
  #include "postgres_fe.h"
  
  #include "input.h"
  #include "settings.h"
  #include "tab-complete.h"
  #include "common.h"
  
  #ifndef WIN32
  #define PSQLHISTORY ".psql_history"
  #else
  #define PSQLHISTORY "psql_history"
  #endif
  
  /* Runtime options for turning off readline and history */
  /* (of course there is no runtime command for doing that :) */
  #ifdef USE_READLINE
  static bool useReadline;
  static bool useHistory;
  char	   *psql_history;
  
  /*
   *	Preserve newlines in saved queries by mapping '\n' to NL_IN_HISTORY
   *
   *	It is assumed NL_IN_HISTORY will never be entered by the user
   *	nor appear inside a multi-byte string.	0x00 is not properly
   *	handled by the readline routines so it can not be used
   *	for this purpose.
   */
  #define NL_IN_HISTORY	0x01
  #endif
  
  #ifdef HAVE_ATEXIT
  static void finishInput(void);
  #else
  /* designed for use with on_exit() */
  static void finishInput(int, void *);
  #endif
  
  
  /*
   * gets_interactive()
   *
   * Gets a line of interactive input, using readline if desired.
   * The result is a malloc'd string.
   *
   * Caller *must* have set up sigint_interrupt_jmp before calling.
   */
  char *
  gets_interactive(const char *prompt)
  {
  #ifdef USE_READLINE
  	if (useReadline)
  	{
  		char	   *result;
  
  		/* Enable SIGINT to longjmp to sigint_interrupt_jmp */
  		sigint_interrupt_enabled = true;
  
  		/* On some platforms, readline is declared as readline(char *) */
  		result = readline((char *) prompt);
  
  		/* Disable SIGINT again */
  		sigint_interrupt_enabled = false;
  
  		return result;
  	}
  #endif
  
  	fputs(prompt, stdout);
  	fflush(stdout);
  	return gets_fromFile(stdin);
  }
  
  
  /*
   * Append the line to the history buffer, making sure there is a trailing '\n'
   */
  void
  pg_append_history(const char *s, PQExpBuffer history_buf)
  {
  #ifdef USE_READLINE
  	if (useHistory && s && s[0])
  	{
  		appendPQExpBufferStr(history_buf, s);
  		if (s[strlen(s) - 1] != '\n')
  			appendPQExpBufferChar(history_buf, '\n');
  	}
  #endif
  }
  
  
  /*
   * Emit accumulated history entry to readline's history mechanism,
   * then reset the buffer to empty.
   *
   * Note: we write nothing if history_buf is empty, so extra calls to this
   * function don't hurt.  There must have been at least one line added by
   * pg_append_history before we'll do anything.
   */
  void
  pg_send_history(PQExpBuffer history_buf)
  {
  #ifdef USE_READLINE
  	static char *prev_hist = NULL;
  
  	char	   *s = history_buf->data;
  	int			i;
  
  	/* Trim any trailing \n's (OK to scribble on history_buf) */
  	for (i = strlen(s) - 1; i >= 0 && s[i] == '\n'; i--)
  		;
  	s[i + 1] = '\0';
  
  	if (useHistory && s[0])
  	{
  		if (((pset.histcontrol & hctl_ignorespace) &&
  			 s[0] == ' ') ||
  			((pset.histcontrol & hctl_ignoredups) &&
  			 prev_hist && strcmp(s, prev_hist) == 0))
  		{
  			/* Ignore this line as far as history is concerned */
  		}
  		else
  		{
  			/* Save each previous line for ignoredups processing */
  			if (prev_hist)
  				free(prev_hist);
  			prev_hist = pg_strdup(s);
  			/* And send it to readline */
  			add_history(s);
  		}
  	}
  
  	resetPQExpBuffer(history_buf);
  #endif
  }
  
  
  /*
   * gets_fromFile
   *
   * Gets a line of noninteractive input from a file (which could be stdin).
   * The result is a malloc'd string, or NULL on EOF or input error.
   *
   * Caller *must* have set up sigint_interrupt_jmp before calling.
   *
   * Note: we re-use a static PQExpBuffer for each call.	This is to avoid
   * leaking memory if interrupted by SIGINT.
   */
  char *
  gets_fromFile(FILE *source)
  {
  	static PQExpBuffer buffer = NULL;
  
  	char		line[1024];
  
  	if (buffer == NULL)			/* first time through? */
  		buffer = createPQExpBuffer();
  	else
  		resetPQExpBuffer(buffer);
  
  	for (;;)
  	{
  		char	   *result;
  
  		/* Enable SIGINT to longjmp to sigint_interrupt_jmp */
  		sigint_interrupt_enabled = true;
  
  		/* Get some data */
  		result = fgets(line, sizeof(line), source);
  
  		/* Disable SIGINT again */
  		sigint_interrupt_enabled = false;
  
  		/* EOF or error? */
  		if (result == NULL)
  		{
  			if (ferror(source))
  			{
  				psql_error("could not read from input file: %s\n",
  						   strerror(errno));
  				return NULL;
  			}
  			break;
  		}
  
  		appendPQExpBufferStr(buffer, line);
  
  		if (PQExpBufferBroken(buffer))
  		{
  			psql_error("out of memory\n");
  			return NULL;
  		}
  
  		/* EOL? */
  		if (buffer->data[buffer->len - 1] == '\n')
  		{
  			buffer->data[buffer->len - 1] = '\0';
  			return pg_strdup(buffer->data);
  		}
  	}
  
  	if (buffer->len > 0)		/* EOF after reading some bufferload(s) */
  		return pg_strdup(buffer->data);
  
  	/* EOF, so return null */
  	return NULL;
  }
  
  
  #ifdef USE_READLINE
  /*
   * Convert newlines to NL_IN_HISTORY for safe saving in readline history file
   */
  static void
  encode_history(void)
  {
  	HIST_ENTRY *cur_hist;
  	char	   *cur_ptr;
  
  	history_set_pos(0);
  	for (cur_hist = current_history(); cur_hist; cur_hist = next_history())
  	{
  		/* some platforms declare HIST_ENTRY.line as const char * */
  		for (cur_ptr = (char *) cur_hist->line; *cur_ptr; cur_ptr++)
  			if (*cur_ptr == '\n')
  				*cur_ptr = NL_IN_HISTORY;
  	}
  }
  
  /*
   * Reverse the above encoding
   */
  static void
  decode_history(void)
  {
  	HIST_ENTRY *cur_hist;
  	char	   *cur_ptr;
  
  	history_set_pos(0);
  	for (cur_hist = current_history(); cur_hist; cur_hist = next_history())
  	{
  		/* some platforms declare HIST_ENTRY.line as const char * */
  		for (cur_ptr = (char *) cur_hist->line; *cur_ptr; cur_ptr++)
  			if (*cur_ptr == NL_IN_HISTORY)
  				*cur_ptr = '\n';
  	}
  }
  #endif   /* USE_READLINE */
  
  
  /*
   * Put any startup stuff related to input in here. It's good to maintain
   * abstraction this way.
   *
   * The only "flag" right now is 1 for use readline & history.
   */
  void
  initializeInput(int flags)
  {
  #ifdef USE_READLINE
  	if (flags & 1)
  	{
  		const char *histfile;
  		char		home[MAXPGPATH];
  
  		useReadline = true;
  		initialize_readline();
  
  		useHistory = true;
  		using_history();
  
  		histfile = GetVariable(pset.vars, "HISTFILE");
  		if (histfile == NULL)
  		{
  			if (get_home_path(home))
  			{
  				psql_history = pg_malloc(strlen(home) + 1 +
  										 strlen(PSQLHISTORY) + 1);
  				snprintf(psql_history, MAXPGPATH, "%s/%s", home, PSQLHISTORY);
  			}
  		}
  		else
  		{
  			psql_history = pg_strdup(histfile);
  			expand_tilde(&psql_history);
  		}
  
  		if (psql_history)
  		{
  			read_history(psql_history);
  			decode_history();
  		}
  	}
  #endif
  
  #ifdef HAVE_ATEXIT
  	atexit(finishInput);
  #else
  	on_exit(finishInput, NULL);
  #endif
  }
  
  
  /*
   * This function is for saving the readline history when user
   * runs \s command or when psql finishes.
   *
   * We have an argument named encodeFlag to handle the cases differently.
   * In case of call via \s we don't really need to encode \n as \x01,
   * but when we save history for Readline we must do that conversion.
   */
  bool
  saveHistory(char *fname, bool encodeFlag)
  {
  #ifdef USE_READLINE
  
  	/*
  	 * Suppressing the write attempt when HISTFILE is set to /dev/null may
  	 * look like a negligible optimization, but it's necessary on e.g. Darwin,
  	 * where write_history will fail because it tries to chmod the target
  	 * file.
  	 */
  	if (useHistory && fname &&
  		strcmp(fname, DEVNULL) != 0)
  	{
  		if (encodeFlag)
  			encode_history();
  
  		/*
  		 * return value of write_history is not standardized across GNU
  		 * readline and libedit.  Therefore, check for errno becoming set to
  		 * see if the write failed.
  		 */
  		errno = 0;
  		(void) write_history(fname);
  		if (errno == 0)
  			return true;
  
  		psql_error("could not save history to file \"%s\": %s\n",
  				   fname, strerror(errno));
  	}
  #else
  	/* only get here in \s case, so complain */
  	psql_error("history is not supported by this installation\n");
  #endif
  
  	return false;
  }
  
  
  static void
  #ifdef HAVE_ATEXIT
  finishInput(void)
  #else
  finishInput(int exitstatus, void *arg)
  #endif
  {
  #ifdef USE_READLINE
  	if (useHistory && psql_history)
  	{
  		int			hist_size;
  
  		hist_size = GetVariableNum(pset.vars, "HISTSIZE", 500, -1, true);
  		if (hist_size >= 0)
  			stifle_history(hist_size);
  
  		saveHistory(psql_history, true);
  		free(psql_history);
  		psql_history = NULL;
  	}
  #endif
  }
  