fish-shell/history.c

/** \file history.c
  History functions, part of the user interface.
*/
#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <errno.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <assert.h>

#include "fallback.h"
#include "util.h"

#include "wutil.h"
#include "history.h"
#include "common.h"
#include "halloc.h"
#include "halloc_util.h"
#include "intern.h"
#include "path.h"

/*
#include "reader.h"
#include "env.h"
#include "sanity.h"
#include "signal.h"
*/

#define WIDE_MODE 0
#define NARROW_MODE 1

/**
   Interval in seconds between automatic history save
*/
#define SAVE_INTERVAL (5*60)

/**
   Number of new history entries to add before automatic history save
*/
#define SAVE_COUNT 5

typedef struct 
{
	const wchar_t *name;
	array_list_t item;
	int pos;
	int has_loaded;
	char *mmap_start;
	size_t mmap_length;
	array_list_t used;	
	time_t save_timestamp;
	int new_count;
	void *item_context;
}
	history_mode_t;

typedef struct 
{
	wchar_t *data;
	time_t timestamp;
}
	item_t;

static hash_table_t *mode_table=0;
static history_mode_t *current_mode=0;

/**
   Add backslashes to all newlines, so that the returning string is
   suitable for writing to the history file. The memory for the return
   value will be reused by subsequent calls to this function.
*/
static wchar_t *history_escape_newlines( wchar_t *in )
{
	static string_buffer_t *out = 0;
	if( !out )
	{
		out = sb_halloc( global_context );
		if( !out )
		{
			DIE_MEM();
		}
	}
	else
	{
		sb_clear( out );
	}
	for( ; *in; in++ )
	{
		if( *in == L'\\' )
		{
			sb_append_char( out, *in );
			if( *(in+1) )
			{
				in++;
				sb_append_char( out, *in );
			}
			else
			{
				/*
				  This is a weird special case. When we are trying to
				  save a string that ends with a backslash, we need to
				  handle it specially, otherwise this command would be
				  combined with the one following it. We hack around
				  this by adding an additional newline.
				*/
				sb_append_char( out, L'\n' );
			}
			
		}
		else if( *in == L'\n' )
		{
			sb_append_char( out, L'\\' );
			sb_append_char( out, *in );
		}
		else
		{
			sb_append_char( out, *in );
		}
		
	}
	return (wchar_t *)out->buff;
}

/**
   Remove backslashes from all newlines. This makes a string from the
   history file better formated for on screen display. The memory for
   the return value will be reused by subsequent calls to this
   function.
*/
static wchar_t *history_unescape_newlines( wchar_t *in )
{
	static string_buffer_t *out = 0;
	if( !out )
	{
		out = sb_halloc( global_context );
		if( !out )
		{
			DIE_MEM();
		}
	}
	else
	{
		sb_clear( out );
	}
	for( ; *in; in++ )
	{
		if( *in == L'\\' )
		{
			if( *(in+1)!= L'\n')
			{
				sb_append_char( out, *in );
			}
		}
		else
		{
			sb_append_char( out, *in );
		}
	}
	return (wchar_t *)out->buff;
}

static int item_is_new( history_mode_t *m, void *d )
{	
	char *begin = (char *)d;

	if( !m->has_loaded || !m->mmap_start || (m->mmap_start == MAP_FAILED ) )
	{
		return 1;		
	}
	
	if( (begin < m->mmap_start) || (begin > (m->mmap_start+m->mmap_length) ) )
	{
		return 1;
	}
	return 0;
}

static item_t *item_get( history_mode_t *m, void *d )
{	
	char *begin = (char *)d;

	if( item_is_new( m, d ) )
	{
		return (item_t *)d;
	}
	else
	{
		
		char *end = m->mmap_start + m->mmap_length;
		char *pos=begin;
		
		int was_backslash = 0;	
		static string_buffer_t *out = 0;
		static item_t narrow_item;
		int first_char = 1;	
		int timestamp_mode = 0;

		narrow_item.timestamp = 0;
							
		if( !out )
		{
			out = sb_halloc( global_context );
			if( !out )
			{
				DIE_MEM();
			}
		}
		else
		{
			sb_clear( out );
		}
		
		while( 1 )
		{
			wchar_t c;
			mbstate_t state;
			size_t res;
			
			memset( &state, 0, sizeof(state) );
			
			res = mbrtowc( &c, pos, end-pos, &state );
			
			if( res == (size_t)-1 )
			{
				pos++;
				continue;
			}
			else if( res == (size_t)-2 )
			{
				break;
			}
			else if( res == (size_t)0 )
			{
				pos++;
				continue;
			}
			pos += res;
			
			if( c == L'\n' )
			{
				if( timestamp_mode )
				{
					wchar_t *time_string = (wchar_t *)out->buff;
					while( *time_string && !iswdigit(*time_string))
						time_string++;
					errno=0;
					
					if( *time_string )
					{
						time_t tm = (time_t)wcstol( time_string, 0, 10 );
					
						if( tm && !errno )
						{
							narrow_item.timestamp = tm;
						}

					}					

					sb_clear( out );
					timestamp_mode = 0;
					continue;
				}
				if( !was_backslash )
					break;
			}
			
			if( first_char )
			{
				if( c == L'#' ) 
					timestamp_mode = 1;
			}
			
			first_char = 0;
			
			sb_append_char( out, c );
			
			was_backslash = ( (c == L'\\') && !was_backslash);
			
		}
		
		narrow_item.data = history_unescape_newlines((wchar_t *)out->buff);
		return &narrow_item;
	}

}

static void item_write( FILE *f, history_mode_t *m, void *v )
{
	item_t *i = item_get( m, v );
	fwprintf( f, L"# %d\n%ls\n", i->timestamp, history_escape_newlines( i->data ) );
}

static void history_destroy_mode( wchar_t *name, history_mode_t *m )
{
	halloc_free( m->item_context );
	
	if( m->mmap_start && (m->mmap_start != MAP_FAILED ))
	{
		munmap( m->mmap_start, m->mmap_length);
	}	
	
	halloc_free( m );
}

static history_mode_t *history_create_mode( const wchar_t *name )
{	
	history_mode_t *new_mode = halloc( 0, sizeof( history_mode_t ));
	new_mode->name = intern(name);
	al_init( &new_mode->item );
	al_init( &new_mode->used );
	
	halloc_register_function( new_mode, (void (*)(void *))&al_destroy, &new_mode->item );
	halloc_register_function( new_mode, (void (*)(void *))&al_destroy, &new_mode->used );

	new_mode->pos = 0;
	new_mode->has_loaded = 0;
	new_mode->mmap_start=0;
	new_mode->mmap_length=0;
	new_mode->save_timestamp=time(0);
	new_mode->new_count = 0;
	
	new_mode->item_context = halloc( 0,0 );

	return new_mode;
	
}

/**
   This function tests if the search string is a match for the given string
*/
static int history_test( const wchar_t *needle, const wchar_t *haystack )
{
	return !!wcsstr( haystack, needle );
}


static wchar_t *history_filename( void *context, const wchar_t *name, const wchar_t *suffix )
{
	wchar_t *path;
	wchar_t *res;	

	if( !current_mode )
		return 0;
	
	path = path_get_config( context );

	if( !path )
		return 0;
	
	res = wcsdupcat2( path, L"/", name, L"_history", suffix?suffix:(void *)0, (void *)0 );
	halloc_register_function( context, &free, res );
	return res;
}

static void history_populate_from_mmap( history_mode_t *m )
{	
	char *begin = m->mmap_start;
	char *end = begin + m->mmap_length;
	char *pos;
	
	array_list_t tmp;
	int ignore_newline = 0;
	int do_push = 1;
	
	al_init( &tmp );
	al_push_all( &tmp, &m->item );
	al_truncate( &m->item, 0 );
	
	for( pos = begin; pos <end; pos++ )
	{
		
		if( do_push )
		{
			ignore_newline = *pos == '#';
			al_push( &m->item, pos );
//			debug( 0, L"Push item at offset %d", pos-begin );				
			do_push = 0;
		}
		
		switch( *pos )
		{
			case '\\':
			{
				pos++;
				break;
			}
			
			case '\n':
			{
				if( ignore_newline )
				{
					ignore_newline = 0;
				}
				else
				{
					do_push = 1;
				}				
				break;
			}
		}
	}	
	
	m->pos += al_get_count( &m->item );
	al_push_all(  &m->item, &tmp );
	al_destroy( &tmp );
//	debug( 0, L"History has %d items", al_get_count( &m->item ));				
	
}


static void history_load( history_mode_t *m )
{
	int fd;
	int ok=0;
	
	void *context;
	wchar_t *filename;

	if( !m )
		return;	
	
	context = halloc( 0, 0 );
	filename = history_filename( context, m->name, 0 );
	
	if( filename )
	{
		if( ( fd = wopen( filename, O_RDONLY ) ) > 0 )
		{
			off_t len = lseek( fd, 0, SEEK_END );
			if( len != (off_t)-1)
			{
				m->mmap_length = (size_t)len;
				if( lseek( fd, 0, SEEK_SET ) == 0 )
				{
					if( (m->mmap_start = mmap( 0, m->mmap_length, PROT_READ, MAP_SHARED, fd, 0 )) != MAP_FAILED )
					{
						ok = 1;
//						debug( 0, L"mmap ok" );
						history_populate_from_mmap( m );
					}
				}
			}
			close( fd );
		}
	}
	
	if( !ok )
	{
//		debug( 0, L"Could not load history file" );
	}
	
	m->has_loaded=1;

	halloc_free( context );
}

static int hash_item_func( void *v )
{
	item_t *i = (item_t *)v;
	return i->timestamp ^ hash_wcs_func( i->data );
}

static int hash_item_cmp( void *v1, void *v2 )
{
	item_t *i1 = (item_t *)v1;
	item_t *i2 = (item_t *)v2;
	return (i1->timestamp == i2->timestamp) && (wcscmp( i1->data, i2->data )==0);	
}

static void history_save_mode( void *n, history_mode_t *m )
{
	FILE *out;
	void *context;
	history_mode_t *on_disk;
	int i;
	int has_new;
	wchar_t *tmp_name;

	/*
	  First check if there are any new entries to save. If not, thenm we can just return
	*/
	for( i=0; i<al_get_count(&m->item); i++ )
	{
		void *ptr = al_get( &m->item, i );
		has_new = item_is_new( m, ptr );
		if( has_new )
		{
			break;
		}
	}
	
	if( !has_new )
	{
		return;
	}
	
	/*
	  Set up on_disk variable to describe the current contents of the history file
	*/
	on_disk = history_create_mode( m->name );
	history_load( on_disk );
	
	context = halloc( 0,0 );

	tmp_name = history_filename( context, m->name, L".tmp" );

	if( tmp_name )
	{
		tmp_name = wcsdup(tmp_name );
		
		if( (out=wfopen( history_filename( context, m->name, L".tmp" ), "w" ) ) )
		{
			hash_table_t mine;
			
			hash_init( &mine, &hash_item_func, &hash_item_cmp );
			
			for( i=0; i<al_get_count(&m->item); i++ )
			{
			void *ptr = al_get( &m->item, i );
			int is_new = item_is_new( m, ptr );
			if( is_new )
			{
				hash_put( &mine, item_get( m, ptr ), L"" );
			}
		}

		/*
		  Re-save the old history
		*/
		for( i=0; i<al_get_count(&on_disk->item); i++ )
		{
			void *ptr = al_get( &on_disk->item, i );
			item_t *i = item_get( on_disk, ptr );
//			assert( i );
			if( !hash_get( &mine, i ) )
				item_write( out, on_disk, ptr );
		}

		hash_destroy( &mine );
		
		/*
		  Add our own items
		*/		
		for( i=0; i<al_get_count(&m->item); i++ )
		{
			void *ptr = al_get( &m->item, i );
			int is_new = item_is_new( m, ptr );
			if( is_new )
				item_write( out, m, ptr );
		}
				
		if( fclose( out ) )
		{
			
		}
		else
		{
			wrename( tmp_name, history_filename( context, m->name, 0 ) );
		}
		}
		free( tmp_name );
	}	

	history_destroy_mode( 0, on_disk);
	
	if( m->mmap_start && (m->mmap_start != MAP_FAILED ) )
		munmap( m->mmap_start, m->mmap_length );
	
	halloc_free( m->item_context );
	m->item_context = halloc( 0, 0 );
	al_truncate( &m->item, 0 );
	al_truncate( &m->used, 0 );
	m->pos = 0;
	m->has_loaded = 0;
	m->mmap_start=0;
	m->mmap_length=0;
	m->save_timestamp=time(0);
	m->new_count = 0;

	halloc_free( context );
}


void history_add( const wchar_t *str )
{
	item_t *i;
	
	if( !current_mode )
		return;
	
	i = halloc( global_context, sizeof(item_t));
	i->data = (wchar_t *)halloc_wcsdup( current_mode->item_context, str );
	i->timestamp = time(0);
	
	al_push( &current_mode->item, i );
	al_truncate( &current_mode->used, 0 );
	current_mode->pos = al_get_count( &current_mode->item );

	current_mode->new_count++;
	
	if( (time(0) > current_mode->save_timestamp+SAVE_INTERVAL) || (current_mode->new_count >= SAVE_COUNT) )
	{
		history_save_mode( 0, current_mode );
	}
	
}

/**
   Check if the specified string has already been used a s a search match
*/
static int history_is_used( const wchar_t  *str )
{
	int i;
	int res =0;
	item_t *it = 0;

	for( i=0; i<al_get_count( &current_mode->used); i++ )
	{
		long idx = al_get_long( &current_mode->used, i );
		it = item_get( current_mode, al_get( &current_mode->item, (int)idx ) );
		if( wcscmp( it->data, str ) == 0 )
		{
			res = 1;
			break;			
		}
		
	}
	return res;
}

const wchar_t *history_prev_match( const wchar_t *needle )
{
	if( current_mode )
	{
		if( current_mode->pos > 0 )
		{
			for( current_mode->pos--; current_mode->pos>=0; current_mode->pos-- )
			{
				item_t *i = item_get( current_mode, al_get( &current_mode->item, current_mode->pos ) );
				wchar_t *haystack = (wchar_t *)i->data;
				
				if( history_test( needle, haystack ) )
				{
					int is_used;
					
					/*
					  This is ugly.  Whenever we call item_get(),
					  there is a chance that the return value of any
					  previous call to item_get will become
					  invalid. The history_is_used function uses the
					  istem_get() function. Therefore, we must create
					  a copy of the haystack string, and if the string
					  is unused, we must call item_get anew.
					*/

					haystack = wcsdup(haystack );
					
					is_used = history_is_used( haystack );
					
					free( haystack );
					
					if( !is_used )
					{
						i = item_get( current_mode, al_get( &current_mode->item, current_mode->pos ) );
						al_push_long( &current_mode->used, current_mode->pos );
						return i->data;
					}
				}
			}
		}
		
		if( !current_mode->has_loaded )
		{
			history_load( current_mode );
			return history_prev_match( needle );
		}
		else
		{
			current_mode->pos=-1;
			if( al_peek_long( &current_mode->used ) != -1 )
				al_push_long( &current_mode->used, -1 );
		}
		
	}
	
	return needle;
}


wchar_t *history_get( int idx )
{
	int len;

	if( !current_mode )
		return 0;
	
	len = al_get_count( &current_mode->item );

	if( (idx >= len ) && !current_mode->has_loaded )
	{
		history_load( current_mode );
		len = al_get_count( &current_mode->item );
	}
	
	if( idx < 0 )
		return 0;
	
	if( idx >= len )
		return 0;
	
	return item_get( current_mode, al_get( &current_mode->item, len - 1 - idx ) )->data;
}

void history_first()
{
	if( current_mode )
	{
		if( !current_mode->has_loaded )
		{
			history_load( current_mode );
		}
		
		current_mode->pos = 0;
	}	
}

void history_reset()
{
	if( current_mode )
	{
		current_mode->pos = al_get_count( &current_mode->item );
		al_truncate( &current_mode->used, 0 );
	}	
}

const wchar_t *history_next_match( const wchar_t *needle)
{
	if( current_mode )
	{
		if( al_get_count( &current_mode->used ) )
		{
			al_pop( &current_mode->used );
			if( al_get_count( &current_mode->used ) )
			{
				current_mode->pos = (int) al_peek_long( &current_mode->used );
				item_t *i = item_get( current_mode, al_get( &current_mode->item, current_mode->pos ) );
				return i->data;
			}
		}

		current_mode->pos = al_get_count( &current_mode->item );

	}
	return needle;	
}


void history_set_mode( const wchar_t *name )
{
	if( !mode_table )
	{
		mode_table = malloc( sizeof(hash_table_t ));
		hash_init( mode_table, &hash_wcs_func, &hash_wcs_cmp );		
	}
	
	current_mode = (history_mode_t *)hash_get( mode_table, name );
	
	if( !current_mode )
	{
		current_mode = history_create_mode( name );
		hash_put( mode_table, name, current_mode );		
	}	
}

void history_init()
{	
}


void history_destroy()
{
	hash_foreach( mode_table, (void (*)(void *, void *))&history_save_mode );
	hash_foreach( mode_table, (void (*)(void *, void *))&history_destroy_mode );
	hash_destroy( mode_table );
	free( mode_table );
	mode_table=0;
}


void history_sanity_check()
{
	
}