1 /* Copyright (C) 1998, 1999 Aladdin Enterprises. All rights reserved. 2 3 This software is provided AS-IS with no warranty, either express or 4 implied. 5 6 This software is distributed under license and may not be copied, 7 modified or distributed except as expressly authorized under the terms 8 of the license contained in the file LICENSE in this distribution. 9 10 For more information about licensing, please refer to 11 http://www.ghostscript.com/licensing/. For information on 12 commercial licensing, go to http://www.artifex.com/licensing/ or 13 contact Artifex Software, Inc., 101 Lucas Valley Road #110, 14 San Rafael, CA 94903, U.S.A., +1(415)492-9861. 15 */ 16 17 /* $Id: gxpageq.h,v 1.5 2002/06/16 08:45:43 lpd Exp $ */ 18 /* Page queue implementation */ 19 20 /* Initial version 2/1/98 by John Desrosiers (soho@crl.com) */ 21 /* 7/17/98 L. Peter Deutsch (ghost@aladdin.com) edited to conform to 22 Ghostscript coding standards */ 23 /* 8/7/98 ghost@aladdin.com fixed bugs in #define st_... statements */ 24 /* 11/3/98 ghost@aladdin.com further updates for coding standards, 25 moves definition of page queue structure to gxpageq.c */ 26 /* 12/1/98 soho@crl.com - Upgraded gx_page_queue_action_t comments */ 27 28 #ifndef gxpageq_INCLUDED 29 # define gxpageq_INCLUDED 30 31 #include "gsmemory.h" 32 #include "gxband.h" 33 #include "gxsync.h" 34 35 /* --------------- Data type definitions --------------------- */ 36 37 /* Action codes for each page queue entry. Each page that the interpreter 38 emits to the page queue can actually be broken down into a sequence of 39 one or more page queue entries. The general form for a given page's 40 sequence of page queue entries can be expressed as: 41 [PARTIAL_PAGE]... [COPY_PAGE [PARTIAL_PAGE]...]... FULL_PAGE 42 where elements in square brackets are optional, and ellipses show 43 repetition. NOTE that a single ACTION_TERMINATE (followed by nothing) can 44 also show up at any point in the page queue in lieu of page descriptions. 45 46 47 PARTIAL_PAGE: The interpreter emits a partial page when the bandlist is 48 too small to contain a page's full representation. Partial pages will 49 be emitted in out-of-memory situations *only* after the interpreter 50 has determined that no further page queue entries are in the page 51 queue, indicating that no further memory can be reclaimed by merely 52 waiting for queued pages to render and free their associated bandlist. 53 54 Note that num_copies is undefined for partial pages: the actual 55 number of pages to render will only be known when ...COPY_PAGE 56 or FULL_PAGE is emitted. 57 58 Partial pages are never imaged. 59 60 61 FULL_PAGE: The interpreter emits a full page when a page description 62 is complete (e.g. showpage), or trashed (e.g. setpagedevice). The 63 page's complete description consists of the FULL_PAGE plus all 64 PARTIAL_PAGEs that immediately precede it in the page queue (and 65 possibly preceding COPY_PAGEs) all the way back to the previous 66 FULL_PAGE (or up to the beginning of queue entries). 67 68 In the case of a trashed page, the page count will be 0. The page 69 queue may choose to not render the 0-count FULL_PAGE queue entry 70 for efficiency. If they have not been rendered, the page queue 71 may choose to also discard (and/or not render) any PARTIAL_PAGEs 72 leading up to the trashed page. The page queue must however take 73 care to not discard any entries leading up to a COPY_PAGE with 74 a non-0 page count that may precede the FULL_PAGE, since COPY_PAGE 75 must be rendered in that case. In any event, a 0-count page will 76 not be imaged. 77 78 In the case of a complete page, the page count will be 0 or greater. 79 The 0-count page is equivalent to a trashed page -- see above. The 80 renderer must ensure that all PARTIAL_PAGEs and COPY_PAGEs leading 81 up to the FULL_PAGE are rendered sequentially before rendering 82 and imaging the FULL_PAGE. 83 84 85 COPY_PAGE: is similar to FULL_PAGE above, except that COPY_PAGE must 86 keep the rendered results, instead of clearing them. COPY_PAGE 87 differs from a partial page in that the page must be imaged, as well 88 as rasterized. This is to support PostScript language "copypage" 89 semantics. 90 91 Note that a 0 page count here does not absolve the renderer from 92 rendering the page queue entries (unless all subsequent COPY_PAGEs 93 the the FULL_PAGE for this page also have a 0 page count), since 94 the results of COPY_PAGE must be available for subsequent pages. 95 96 97 TERMINATE: This entry can appear at any time in the page queue. It 98 will be the last entry to ever appear in the queue. The semantics 99 of this entry require all prior non-zero-count COPY_PAGEs and 100 FULL_PAGEs to be imaged. Any trailing PARTIAL_PAGEs may optionally 101 be rendered, but should not be imaged. 102 */ 103 typedef enum { 104 GX_PAGE_QUEUE_ACTION_PARTIAL_PAGE, 105 GX_PAGE_QUEUE_ACTION_FULL_PAGE, 106 GX_PAGE_QUEUE_ACTION_COPY_PAGE, 107 GX_PAGE_QUEUE_ACTION_TERMINATE 108 } gx_page_queue_action_t; 109 110 /* 111 * Define the structure used to manage a page queue. 112 * A page queue is a monitor-locked FIFO which holds completed command 113 * list files ready for rendering. 114 */ 115 #ifndef gx_page_queue_DEFINED 116 # define gx_page_queue_DEFINED 117 typedef struct gx_page_queue_s gx_page_queue_t; 118 #endif 119 120 /* 121 * Define a page queue entry object. 122 */ 123 typedef struct gx_page_queue_entry_s gx_page_queue_entry_t; 124 struct gx_page_queue_entry_s { 125 gx_band_page_info_t page_info; 126 gx_page_queue_action_t action; /* action code */ 127 int num_copies; /* number of copies to render, only defined */ 128 /* if action == ...FULL_PAGE or ...COPY_PAGE */ 129 gx_page_queue_entry_t *next; /* link to next in queue */ 130 gx_page_queue_t *queue; /* link to queue the entry is in */ 131 }; 132 133 #define private_st_gx_page_queue_entry()\ 134 gs_private_st_ptrs2(st_gx_page_queue_entry, gx_page_queue_entry_t,\ 135 "gx_page_queue_entry",\ 136 gx_page_queue_entry_enum_ptrs, gx_page_queue_entry_reloc_ptrs,\ 137 next, queue) 138 139 /* -------------- Public Procedure Declaraions --------------------- */ 140 141 /* Allocate a page queue. */ 142 gx_page_queue_t *gx_page_queue_alloc(gs_memory_t *mem); 143 144 /* 145 * Allocate and initialize a page queue entry. 146 * All page queue entries must be allocated by this routine. 147 */ 148 /* rets ptr to allocated object, 0 if VM error */ 149 gx_page_queue_entry_t * 150 gx_page_queue_entry_alloc( 151 gx_page_queue_t * queue /* queue that entry is being alloc'd for */ 152 ); 153 154 /* 155 * Free a page queue entry. 156 * All page queue entries must be destroyed by this routine. 157 */ 158 void gx_page_queue_entry_free( 159 gx_page_queue_entry_t * entry /* entry to free up */ 160 ); 161 162 /* 163 * Free the page_info resources held by the pageq entry. Used to free 164 * pages' clist, typically after rendering. Note that this routine is NOT 165 * called implicitly by gx_page_queue_entry_free, since page clist may be 166 * managed separately from page queue entries. However, unless you are 167 * managing clist separately, you must call this routine before freeing the 168 * pageq entry itself (via gx_page_queue_entry_free), or you will leak 169 * memory (lots). 170 */ 171 void gx_page_queue_entry_free_page_info( 172 gx_page_queue_entry_t * entry /* entry to free up */ 173 ); 174 175 /* 176 * Initialize a page queue; this must be done before it can be used. 177 * This routine allocates & inits various necessary structures and will 178 * fail if insufficient memory is available. 179 */ 180 /* -ve error code, or 0 */ 181 int gx_page_queue_init( 182 gx_page_queue_t * queue, /* page queue to init */ 183 gs_memory_t * memory /* allocator for dynamic memory */ 184 ); 185 186 /* 187 * Destroy a page queue which was initialized by gx_page_queue_init. 188 * Any page queue entries in the queue are released and destroyed; 189 * dynamic allocations are released. 190 */ 191 void gx_page_queue_dnit( 192 gx_page_queue_t * queue /* page queue to dnit */ 193 ); 194 195 /* 196 * If there are any pages in queue, wait until one of them finishes 197 * rendering. Typically called by writer's out-of-memory error handlers 198 * that want to wait until some memory has been freed. 199 */ 200 /* rets 0 if no pages were waiting for rendering, 1 if actually waited */ 201 int gx_page_queue_wait_one_page( 202 gx_page_queue_t * queue /* queue to wait on */ 203 ); 204 205 /* 206 * Wait until all (if any) pages in queue have finished rendering. Typically 207 * called by writer operations which need to drain the page queue before 208 * continuing. 209 */ 210 void gx_page_queue_wait_until_empty( 211 gx_page_queue_t * queue /* page queue to wait on */ 212 ); 213 214 /* 215 * Add a pageq queue entry to the end of the page queue. If an unsatisfied 216 * reader thread has an outstanding gx_page_queue_start_deque(), wake it up. 217 */ 218 void gx_page_queue_enqueue( 219 gx_page_queue_entry_t * entry /* entry to add */ 220 ); 221 222 /* 223 * Allocate & construct a pageq entry, then add to the end of the pageq as 224 * in gx_page_queue_enqueue. If unable to allocate a new pageq entry, uses 225 * the pre-allocated reserve entry held in the pageq. When using the reserve 226 * pageq entry, wait until enough pages have been rendered to allocate a new 227 * reserve for next time -- this should always succeed & returns eFatal if not. 228 * Unless the reserve was used, does not wait for any rendering to complete. 229 * Typically called by writer when it has a (partial) page ready for rendering. 230 */ 231 /* rets 0 ok, gs_error_Fatal if error */ 232 int gx_page_queue_add_page( 233 gx_page_queue_t * queue, /* page queue to add to */ 234 gx_page_queue_action_t action, /* action code to queue */ 235 const gx_band_page_info_t * page_info, /* bandinfo incl. bandlist */ 236 int page_count /* # of copies to print if final "print," */ 237 /* 0 if partial page, -1 if cancel */ 238 ); 239 240 /* 241 * Retrieve the least-recently added queue entry from the pageq. If no 242 * entry is available, waits on a signal from gx_page_queue_enqueue. Must 243 * eventually be followed by a call to gx_page_queue_finish_dequeue for the 244 * same pageq entry. 245 * Even though the pageq is actually removed from the pageq, a mark is made in 246 * the pageq to indicate that the pageq is not "empty" until the 247 * gx_page_queue_finish_dequeue; this is for the benefit of 248 * gx_page_queue_wait_???, since the completing the current page's rendering 249 * may free more memory. 250 * Typically called by renderer thread loop, which looks like: 251 do { 252 gx_page_queue_start_deqeueue(...); 253 render_retrieved_entry(...); 254 gx_page_queue_finish_dequeue(...); 255 } while (some condition); 256 */ 257 gx_page_queue_entry_t * /* removed entry */ 258 gx_page_queue_start_dequeue( 259 gx_page_queue_t * queue /* page queue to retrieve from */ 260 ); 261 262 /* 263 * Free the pageq entry and its associated band list data, then signal any 264 * waiting threads. Typically used to indicate completion of rendering the 265 * pageq entry. Note that this is different from gx_page_queue_entry_free, 266 * which does not free the band list data (a separate call of 267 * gx_page_queue_entry_free_page_info is required). 268 */ 269 void gx_page_queue_finish_dequeue( 270 gx_page_queue_entry_t * entry /* entry that was retrieved to delete */ 271 ); 272 273 #endif /*!defined(gxpageq_INCLUDED) */ 274