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author | ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-05-23 22:52:19 +0000 |
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committer | ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-05-23 22:52:19 +0000 |
commit | 7c4ff2d3322753479b3974105e5100b6f4e43001 (patch) | |
tree | 826dcf85cb1bf4b8a3fae0448b0be1554e2e0205 /cont.c | |
parent | d086dfc513d319bae72002c8bb7e9da9d6d7cf1e (diff) | |
download | ruby-7c4ff2d3322753479b3974105e5100b6f4e43001.tar.gz |
* cont.c: support callcc which everyone love.
incomplete. please give me bug reports.
* common.mk, inits.c, thread.c: ditto.
* yarvcore.c: export thread_mark().
* yarvcore.h: disable value cache option.
* eval_intern.h: set th_get_ruby_level_cfp to inline.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12380 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'cont.c')
-rw-r--r-- | cont.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/cont.c b/cont.c new file mode 100644 index 0000000000..099cdde070 --- /dev/null +++ b/cont.c @@ -0,0 +1,302 @@ +/********************************************************************** + + cont.c - + + $Author$ + $Date$ + created at: Thu May 23 09:03:43 2007 + + Copyright (C) 2007 Koichi Sasada + +**********************************************************************/ + +#include "ruby.h" +#include "yarvcore.h" +#include "gc.h" +#include "eval_intern.h" + +typedef struct rb_continuation_struct { + rb_thread_t saved_thread; + rb_jmpbuf_t jmpbuf; + VALUE retval; + VALUE *vm_stack; + VALUE *machine_stack; + VALUE *machine_stack_src; + int machine_stack_size; +} rb_continuation_t; + +#define GetContPtr(obj, ptr) \ + Data_Get_Struct(obj, rb_continuation_t, ptr) + +NOINLINE(static VALUE cont_capture(volatile int *stat)); + +void rb_thread_mark(rb_thread_t *th); + +static void +cont_mark(void *ptr) +{ + MARK_REPORT_ENTER("cont"); + if (ptr) { + rb_continuation_t *cont = ptr; + rb_gc_mark(cont->retval); + rb_thread_mark(&cont->saved_thread); + + if (cont->vm_stack) { + rb_gc_mark_locations(cont->vm_stack, + cont->vm_stack + cont->saved_thread.stack_size); + } + + if (cont->machine_stack) { + rb_gc_mark_locations(cont->machine_stack, + cont->machine_stack + cont->machine_stack_size); + } + } + MARK_REPORT_LEAVE("cont"); +} + +static void +cont_free(void *ptr) +{ + FREE_REPORT_ENTER("cont"); + if (ptr) { + rb_continuation_t *cont = ptr; + FREE_UNLESS_NULL(cont->machine_stack); + FREE_UNLESS_NULL(cont->vm_stack); + ruby_xfree(ptr); + } + FREE_REPORT_LEAVE("cont"); +} + +static VALUE +cont_capture(volatile int *stat) +{ + rb_continuation_t *cont; + VALUE contval; + rb_thread_t *th = GET_THREAD(), *sth; + int size; + + contval = Data_Make_Struct(rb_cCont, rb_continuation_t, + cont_mark, cont_free, cont); + + /* save context */ + cont->saved_thread = *th; + sth = &cont->saved_thread; + sth->stack = 0; /* clear to skip GC marking */ + cont->vm_stack = ALLOC_N(VALUE, sth->stack_size); + MEMCPY(cont->vm_stack, th->stack, VALUE, sth->stack_size); + + rb_gc_set_stack_end(&th->machine_stack_end); + if (th->machine_stack_start > th->machine_stack_end) { + size = cont->machine_stack_size = th->machine_stack_start - th->machine_stack_end; + cont->machine_stack_src = th->machine_stack_end; + } + else { + size = cont->machine_stack_size = th->machine_stack_end - th->machine_stack_start; + cont->machine_stack_src = th->machine_stack_start; + } + + cont->machine_stack = ALLOC_N(VALUE, size); + MEMCPY(cont->machine_stack, cont->machine_stack_src, VALUE, size); + + if (ruby_setjmp(cont->jmpbuf)) { + VALUE retval; + + retval = cont->retval; + cont->retval = Qnil; + *stat = 1; + return retval; + } + else { + *stat = 0; + return contval; + } +} + +static void +cont_restore_context_1(rb_continuation_t *cont) +{ + rb_thread_t *th = GET_THREAD(), *sth = &cont->saved_thread; + + /* restore thread context */ + MEMCPY(th->stack, cont->vm_stack, VALUE, sth->stack_size); + + th->cfp = sth->cfp; + th->safe_level = sth->safe_level; + th->raised_flag = sth->raised_flag; + th->state = sth->state; + th->status = sth->status; + th->tag = sth->tag; + + /* restore machine stack */ + MEMCPY(cont->machine_stack_src, cont->machine_stack, + VALUE, cont->machine_stack_size); + + ruby_longjmp(cont->jmpbuf, 1); +} + +NORETURN(NOINLINE(static void restore_context_0(rb_continuation_t *, VALUE *))); + +static void +cont_restore_context_0(rb_continuation_t *cont, VALUE *addr_in_prev_frame) +{ +#define STACK_PAD_SIZE 1024 + VALUE space[STACK_PAD_SIZE]; + +#if STACK_GROW_DIRECTION < 0 /* downward */ + if (addr_in_prev_frame > cont->machine_stack_src) { + cont_restore_context_0(cont, &space[0]); + } +#elif STACK_GROW_DIRECTION > 0 /* upward */ + if (addr_in_prev_frame < cont->machine_stack_src + cont->machine_stack_size) { + cont_restore_context_0(cont, &space[STACK_PAD_SIZE-1]); + } +#else + if (addr_in_prev_frame > &space[0]) { + /* Stack grows downward */ + if (addr_in_prev_frame > cont->saved_thread.machine_stack_src) { + cont_restore_context_0(cont, &space[0]); + } + } + else { + /* Stack grows upward */ + if (addr_in_prev_frame < cont->machine_stack_src + cont->machine_stack_size) { + cont_restore_context_0(cont, &space[STACK_PAD_SIZE-1]); + } + } +#endif + cont_restore_context_1(cont); +} + +/* + * Document-class: Continuation + * + * Continuation objects are generated by + * <code>Kernel#callcc</code>. They hold a return address and execution + * context, allowing a nonlocal return to the end of the + * <code>callcc</code> block from anywhere within a program. + * Continuations are somewhat analogous to a structured version of C's + * <code>setjmp/longjmp</code> (although they contain more state, so + * you might consider them closer to threads). + * + * For instance: + * + * arr = [ "Freddie", "Herbie", "Ron", "Max", "Ringo" ] + * callcc{|$cc|} + * puts(message = arr.shift) + * $cc.call unless message =~ /Max/ + * + * <em>produces:</em> + * + * Freddie + * Herbie + * Ron + * Max + * + * This (somewhat contrived) example allows the inner loop to abandon + * processing early: + * + * callcc {|cont| + * for i in 0..4 + * print "\n#{i}: " + * for j in i*5...(i+1)*5 + * cont.call() if j == 17 + * printf "%3d", j + * end + * end + * } + * print "\n" + * + * <em>produces:</em> + * + * 0: 0 1 2 3 4 + * 1: 5 6 7 8 9 + * 2: 10 11 12 13 14 + * 3: 15 16 + */ + +VALUE rb_cCont; + +/* + * call-seq: + * callcc {|cont| block } => obj + * + * Generates a <code>Continuation</code> object, which it passes to the + * associated block. Performing a <em>cont</em><code>.call</code> will + * cause the <code>callcc</code> to return (as will falling through the + * end of the block). The value returned by the <code>callcc</code> is + * the value of the block, or the value passed to + * <em>cont</em><code>.call</code>. See class <code>Continuation</code> + * for more details. Also see <code>Kernel::throw</code> for + * an alternative mechanism for unwinding a call stack. + */ + +static VALUE +rb_callcc(VALUE self) +{ + volatile int called; + volatile VALUE val = cont_capture(&called); + + if (called) { + return val; + } + else { + return rb_yield(val); + } +} + +/* + * call-seq: + * cont.call(args, ...) + * cont[args, ...] + * + * Invokes the continuation. The program continues from the end of the + * <code>callcc</code> block. If no arguments are given, the original + * <code>callcc</code> returns <code>nil</code>. If one argument is + * given, <code>callcc</code> returns it. Otherwise, an array + * containing <i>args</i> is returned. + * + * callcc {|cont| cont.call } #=> nil + * callcc {|cont| cont.call 1 } #=> 1 + * callcc {|cont| cont.call 1, 2, 3 } #=> [1, 2, 3] + */ + +static VALUE +rb_cont_call(int argc, VALUE *argv, VALUE contval) +{ + rb_continuation_t *cont; + rb_thread_t *th = GET_THREAD(); + GetContPtr(contval, cont); + + if (cont->saved_thread.value != th->value) { + rb_raise(rb_eRuntimeError, "continuation called across threads"); + } + /* TODO: check "continuation called across trap" */ + printf("--> %p\n", cont); + + switch(argc) { + case 0: + cont->retval = Qnil; + break; + case 1: + cont->retval = argv[0]; + break; + default: + cont->retval = rb_ary_new4(argc, argv); + break; + } + + cont_restore_context_0(cont, (VALUE *)&cont); + return Qnil; /* unreachable */ +} + +void +Init_Cont(void) +{ + rb_cCont = rb_define_class("Continuation", rb_cObject); + rb_undef_alloc_func(rb_cCont); + rb_undef_method(CLASS_OF(rb_cCont), "new"); + rb_define_method(rb_cCont, "call", rb_cont_call, -1); + rb_define_method(rb_cCont, "[]", rb_cont_call, -1); + rb_define_global_function("callcc", rb_callcc, 0); +} + |