1 /* Copyright (C) 1998, 1999 artofcode LLC. All rights reserved. 2 3 This program is free software; you can redistribute it and/or modify it 4 under the terms of the GNU General Public License as published by the 5 Free Software Foundation; either version 2 of the License, or (at your 6 option) any later version. 7 8 This program is distributed in the hope that it will be useful, but 9 WITHOUT ANY WARRANTY; without even the implied warranty of 10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 General Public License for more details. 12 13 You should have received a copy of the GNU General Public License along 14 with this program; if not, write to the Free Software Foundation, Inc., 15 59 Temple Place, Suite 330, Boston, MA, 02111-1307. 16 17 */ 18 19 /*$Id: gxpageq.h,v 1.2.6.1.2.1 2003/01/17 00:49:04 giles Exp $ */ 20 /* Page queue implementation */ 21 22 /* Initial version 2/1/98 by John Desrosiers (soho@crl.com) */ 23 /* 7/17/98 L. Peter Deutsch (ghost@aladdin.com) edited to conform to 24 Ghostscript coding standards */ 25 /* 8/7/98 ghost@aladdin.com fixed bugs in #define st_... statements */ 26 /* 11/3/98 ghost@aladdin.com further updates for coding standards, 27 moves definition of page queue structure to gxpageq.c */ 28 /* 12/1/98 soho@crl.com - Upgraded gx_page_queue_action_t comments */ 29 30 #ifndef gxpageq_INCLUDED 31 # define gxpageq_INCLUDED 32 33 #include "gsmemory.h" 34 #include "gxband.h" 35 #include "gxsync.h" 36 37 /* --------------- Data type definitions --------------------- */ 38 39 /* Action codes for each page queue entry. Each page that the interpreter 40 emits to the page queue can actually be broken down into a sequence of 41 one or more page queue entries. The general form for a given page's 42 sequence of page queue entries can be expressed as: 43 [PARTIAL_PAGE]... [COPY_PAGE [PARTIAL_PAGE]...]... FULL_PAGE 44 where elements in square brackets are optional, and ellipses show 45 repetition. NOTE that a single ACTION_TERMINATE (followed by nothing) can 46 also show up at any point in the page queue in lieu of page descriptions. 47 48 49 PARTIAL_PAGE: The interpreter emits a partial page when the bandlist is 50 too small to contain a page's full representation. Partial pages will 51 be emitted in out-of-memory situations *only* after the interpreter 52 has determined that no further page queue entries are in the page 53 queue, indicating that no further memory can be reclaimed by merely 54 waiting for queued pages to render and free their associated bandlist. 55 56 Note that num_copies is undefined for partial pages: the actual 57 number of pages to render will only be known when ...COPY_PAGE 58 or FULL_PAGE is emitted. 59 60 Partial pages are never imaged. 61 62 63 FULL_PAGE: The interpreter emits a full page when a page description 64 is complete (e.g. showpage), or trashed (e.g. setpagedevice). The 65 page's complete description consists of the FULL_PAGE plus all 66 PARTIAL_PAGEs that immediately precede it in the page queue (and 67 possibly preceding COPY_PAGEs) all the way back to the previous 68 FULL_PAGE (or up to the beginning of queue entries). 69 70 In the case of a trashed page, the page count will be 0. The page 71 queue may choose to not render the 0-count FULL_PAGE queue entry 72 for efficiency. If they have not been rendered, the page queue 73 may choose to also discard (and/or not render) any PARTIAL_PAGEs 74 leading up to the trashed page. The page queue must however take 75 care to not discard any entries leading up to a COPY_PAGE with 76 a non-0 page count that may precede the FULL_PAGE, since COPY_PAGE 77 must be rendered in that case. In any event, a 0-count page will 78 not be imaged. 79 80 In the case of a complete page, the page count will be 0 or greater. 81 The 0-count page is equivalent to a trashed page -- see above. The 82 renderer must ensure that all PARTIAL_PAGEs and COPY_PAGEs leading 83 up to the FULL_PAGE are rendered sequentially before rendering 84 and imaging the FULL_PAGE. 85 86 87 COPY_PAGE: is similar to FULL_PAGE above, except that COPY_PAGE must 88 keep the rendered results, instead of clearing them. COPY_PAGE 89 differs from a partial page in that the page must be imaged, as well 90 as rasterized. This is to support PostScript language "copypage" 91 semantics. 92 93 Note that a 0 page count here does not absolve the renderer from 94 rendering the page queue entries (unless all subsequent COPY_PAGEs 95 the the FULL_PAGE for this page also have a 0 page count), since 96 the results of COPY_PAGE must be available for subsequent pages. 97 98 99 TERMINATE: This entry can appear at any time in the page queue. It 100 will be the last entry to ever appear in the queue. The semantics 101 of this entry require all prior non-zero-count COPY_PAGEs and 102 FULL_PAGEs to be imaged. Any trailing PARTIAL_PAGEs may optionally 103 be rendered, but should not be imaged. 104 */ 105 typedef enum { 106 GX_PAGE_QUEUE_ACTION_PARTIAL_PAGE, 107 GX_PAGE_QUEUE_ACTION_FULL_PAGE, 108 GX_PAGE_QUEUE_ACTION_COPY_PAGE, 109 GX_PAGE_QUEUE_ACTION_TERMINATE 110 } gx_page_queue_action_t; 111 112 /* 113 * Define the structure used to manage a page queue. 114 * A page queue is a monitor-locked FIFO which holds completed command 115 * list files ready for rendering. 116 */ 117 #ifndef gx_page_queue_DEFINED 118 # define gx_page_queue_DEFINED 119 typedef struct gx_page_queue_s gx_page_queue_t; 120 #endif 121 122 /* 123 * Define a page queue entry object. 124 */ 125 typedef struct gx_page_queue_entry_s gx_page_queue_entry_t; 126 struct gx_page_queue_entry_s { 127 gx_band_page_info_t page_info; 128 gx_page_queue_action_t action; /* action code */ 129 int num_copies; /* number of copies to render, only defined */ 130 /* if action == ...FULL_PAGE or ...COPY_PAGE */ 131 gx_page_queue_entry_t *next; /* link to next in queue */ 132 gx_page_queue_t *queue; /* link to queue the entry is in */ 133 }; 134 135 #define private_st_gx_page_queue_entry()\ 136 gs_private_st_ptrs2(st_gx_page_queue_entry, gx_page_queue_entry_t,\ 137 "gx_page_queue_entry",\ 138 gx_page_queue_entry_enum_ptrs, gx_page_queue_entry_reloc_ptrs,\ 139 next, queue) 140 141 /* -------------- Public Procedure Declaraions --------------------- */ 142 143 /* Allocate a page queue. */ 144 gx_page_queue_t *gx_page_queue_alloc(P1(gs_memory_t *mem)); 145 146 /* 147 * Allocate and initialize a page queue entry. 148 * All page queue entries must be allocated by this routine. 149 */ 150 /* rets ptr to allocated object, 0 if VM error */ 151 gx_page_queue_entry_t * 152 gx_page_queue_entry_alloc(P1( 153 gx_page_queue_t * queue /* queue that entry is being alloc'd for */ 154 )); 155 156 /* 157 * Free a page queue entry. 158 * All page queue entries must be destroyed by this routine. 159 */ 160 void gx_page_queue_entry_free(P1( 161 gx_page_queue_entry_t * entry /* entry to free up */ 162 )); 163 164 /* 165 * Free the page_info resources held by the pageq entry. Used to free 166 * pages' clist, typically after rendering. Note that this routine is NOT 167 * called implicitly by gx_page_queue_entry_free, since page clist may be 168 * managed separately from page queue entries. However, unless you are 169 * managing clist separately, you must call this routine before freeing the 170 * pageq entry itself (via gx_page_queue_entry_free), or you will leak 171 * memory (lots). 172 */ 173 void gx_page_queue_entry_free_page_info(P1( 174 gx_page_queue_entry_t * entry /* entry to free up */ 175 )); 176 177 /* 178 * Initialize a page queue; this must be done before it can be used. 179 * This routine allocates & inits various necessary structures and will 180 * fail if insufficient memory is available. 181 */ 182 /* -ve error code, or 0 */ 183 int gx_page_queue_init(P2( 184 gx_page_queue_t * queue, /* page queue to init */ 185 gs_memory_t * memory /* allocator for dynamic memory */ 186 )); 187 188 /* 189 * Destroy a page queue which was initialized by gx_page_queue_init. 190 * Any page queue entries in the queue are released and destroyed; 191 * dynamic allocations are released. 192 */ 193 void gx_page_queue_dnit(P1( 194 gx_page_queue_t * queue /* page queue to dnit */ 195 )); 196 197 /* 198 * If there are any pages in queue, wait until one of them finishes 199 * rendering. Typically called by writer's out-of-memory error handlers 200 * that want to wait until some memory has been freed. 201 */ 202 /* rets 0 if no pages were waiting for rendering, 1 if actually waited */ 203 int gx_page_queue_wait_one_page(P1( 204 gx_page_queue_t * queue /* queue to wait on */ 205 )); 206 207 /* 208 * Wait until all (if any) pages in queue have finished rendering. Typically 209 * called by writer operations which need to drain the page queue before 210 * continuing. 211 */ 212 void gx_page_queue_wait_until_empty(P1( 213 gx_page_queue_t * queue /* page queue to wait on */ 214 )); 215 216 /* 217 * Add a pageq queue entry to the end of the page queue. If an unsatisfied 218 * reader thread has an outstanding gx_page_queue_start_deque(), wake it up. 219 */ 220 void gx_page_queue_enqueue(P1( 221 gx_page_queue_entry_t * entry /* entry to add */ 222 )); 223 224 /* 225 * Allocate & construct a pageq entry, then add to the end of the pageq as 226 * in gx_page_queue_enqueue. If unable to allocate a new pageq entry, uses 227 * the pre-allocated reserve entry held in the pageq. When using the reserve 228 * pageq entry, wait until enough pages have been rendered to allocate a new 229 * reserve for next time -- this should always succeed & returns eFatal if not. 230 * Unless the reserve was used, does not wait for any rendering to complete. 231 * Typically called by writer when it has a (partial) page ready for rendering. 232 */ 233 /* rets 0 ok, gs_error_Fatal if error */ 234 int gx_page_queue_add_page(P4( 235 gx_page_queue_t * queue, /* page queue to add to */ 236 gx_page_queue_action_t action, /* action code to queue */ 237 const gx_band_page_info_t * page_info, /* bandinfo incl. bandlist */ 238 int page_count /* # of copies to print if final "print," */ 239 /* 0 if partial page, -1 if cancel */ 240 )); 241 242 /* 243 * Retrieve the least-recently added queue entry from the pageq. If no 244 * entry is available, waits on a signal from gx_page_queue_enqueue. Must 245 * eventually be followed by a call to gx_page_queue_finish_dequeue for the 246 * same pageq entry. 247 * Even though the pageq is actually removed from the pageq, a mark is made in 248 * the pageq to indicate that the pageq is not "empty" until the 249 * gx_page_queue_finish_dequeue; this is for the benefit of 250 * gx_page_queue_wait_???, since the completing the current page's rendering 251 * may free more memory. 252 * Typically called by renderer thread loop, which looks like: 253 do { 254 gx_page_queue_start_deqeueue(...); 255 render_retrieved_entry(...); 256 gx_page_queue_finish_dequeue(...); 257 } while (some condition); 258 */ 259 gx_page_queue_entry_t * /* removed entry */ 260 gx_page_queue_start_dequeue(P1( 261 gx_page_queue_t * queue /* page queue to retrieve from */ 262 )); 263 264 /* 265 * Free the pageq entry and its associated band list data, then signal any 266 * waiting threads. Typically used to indicate completion of rendering the 267 * pageq entry. Note that this is different from gx_page_queue_entry_free, 268 * which does not free the band list data (a separate call of 269 * gx_page_queue_entry_free_page_info is required). 270 */ 271 void gx_page_queue_finish_dequeue(P1( 272 gx_page_queue_entry_t * entry /* entry that was retrieved to delete */ 273 )); 274 275 #endif /*!defined(gxpageq_INCLUDED) */ 276