On Sun, 13 May 2007 22:46:15 -0700 Mike Mattie <[EMAIL PROTECTED]> wrote:
> Hello, > I figured anyone who actually makes it from top to bottom of the RFC might want to see what it looks like in C code. Since I will be gone for a bit I am attaching my in-progress copy of src/library.c . It is not even compiling AFAIK , but it is fairly close, and has the design fully sketched out. I am also attaching gen-paths. It is a hack in the derogatory sense of the word, but if anyone wants to play with the ideas in the RFC it will help. I use it to generate builtin-library-paths.c library.paths is the input file for gen-paths happy parrot hacking, > Cheers, > Mike Mattie - [EMAIL PROTECTED] > > > >
/* Copyright (C) 2004-2007, The Perl Foundation. $Id: library.c 18482 2007-05-09 11:16:10Z paultcochrane $ =head1 NAME src/library.c - Interface to Parrot's bytecode library =head1 DESCRIPTION This file contains a C function to access parrot's bytecode library functions. =head2 Functions =over 4 =cut */ #include <stdarg.h> #include "parrot/parrot.h" #include "parrot/library.h" #include "library.str" /* used internally by diagnostics , ASCII text string names for the loader. * TODO: internationalization. */ static const char* const loader_names[] = { 'ARCH', 'BYTECODE', 'INCLUDE', 'SRC' }; /* create a loader table , indexed by the three loader paths enumerated * by enum_runtime_ft in parrot/include/library.h. Each namespace has * a path/extension search table for a shared object loader, a byte-code * loader, and a source-code loader. * * for a shared object loader this is a little wastefull, but the tables * are not duplicated. If a namespace does not define a path/extension * search table, the "parrot" table will be used. */ static PMC* create_loader_table(Interp* interp) { PMC *table; table = pmc_new(interp, enum_class_FixedPMCArray); VTABLE_set_integer_native(interp, table, PARROT_RUNTIME_FT_SIZE ); return table; } /* return an existing load-table , or create one and attach it * to the namespace. */ static PMC* get_load_table_for_populate(Interp* interp, PMC* lib_paths, STRING* ns) { PMC *table; if ( VTABLE_exists_keyed_str(interp, lib_paths, ns) ) return VTABLE_get_pmc_keyed_str(interp, lib_paths, ns ); table = create_loader_table(interp); VTABLE_set_pmc_keyed_str(interp, lib_paths, ns, table); return table; } /* create a search space. Loaders will want to iterate through a * path space, and an extension space. These are enumerated * in enum_search_space. */ typedef enum { SEARCH_TABLE_PATH = 0, SEARCH_TABLE_EXT, SEARCH_TABLE_SIZE } enum_search_space; static PMC* create_search_table(Interp* interp) { PMC *table; table = pmc_new(interp, enum_class_FixedPMCArray); VTABLE_set_integer_native(interp, table, SEARCH_TABLE_SIZE); return table; } static PMC* get_search_table_for_populate(Interp* interp, PMC* load_table, int loader ) { PMC *table; if ( VTABLE_exists_keyed_int( interp, load_table, loader ) ) return VTABLE_get_pmc_keyed_int(interp, load_table, loader ); table = create_search_table(interp); VTABLE_set_pmc_keyed_int(interp, load_table, loader, table); return table; } /* A search space is a simple dynamic array, or list of * name varaiations (path or extension) to try. */ static PMC* create_search_space(Interp* interp) { return pmc_new(interp, enum_class_ResizableStringArray); } static PMC* get_search_space_for_populate(Interp* interp, PMC* search_table , enum_search_space search_space) { PMC *new_table; if ( VTABLE_exists_keyed_int( interp, search_table , search_space ) ) return VTABLE_get_pmc_keyed_int(interp, search_table, search_space ); new_table = create_search_space(interp); VTABLE_set_pmc_keyed_int(interp, search_table, search_space , new_table ); return new_table; } static void populate_search_space(Interp* interp, /* the loader table for the namespace */ PMC* load_table, enum_runtime_ft loader, /* search space index */ enum_search_space search_space, /* the entry to add */ STRING* entry) { PMC *search_table, *search_list; search_list = get_search_space_for_populate(interp, get_search_table_for_populate(interp, load_table,loader), search_space); VTABLE_push_string(interp, search_list, entry); } /* load_prefer is a toggle to prefer either the most low level form of a module * (compiled) or the highest level form of a module. * * Users will typically want the compiled versions. This is also the perl5 * behavior as well. * * Users wanting a more dynamic interaction can export PARROT_PREFER_SOURCE * to reverse the default behavior. * * FUTURE: If a value for PARROT_PREFER_SOURCE is honored it should be * a path spec of directories for which source will be loaded over compiled * objects. */ typedef enum { PREFER_COMPILE, PREFER_SOURCE } enum_load_prefer; static enum_load_prefer load_prefer = PREFER_COMPILE; static int query_load_prefer ( Interp* interp ) { int free_it; char *env; env = Parrot_getenv("PARROT_PREFER_SOURCE", &free_it); if (env) { if (free_it) mem_sys_free(env); return 1; } return 0; } static int next_by_load_prefer (int current) { return current + ( PREFER_COMPILE == load_prefer ) ? 1 : -1; } static int bound_by_load_prefer(int *lower_bound, *upper_bound) { int swap; if ( PREFER_COMPILE == load_prefer ) { *lower_bound = 0; return; } *lower_bound = *upper_bound - 1; *upper_bound = -1; } /* =item C<void parrot_init_library_paths(Interp *)> TODO: doc. =cut */ #include "builtin-loader-paths.c" void parrot_init_library_paths(Interp *interp) { PMC *iglobals, *lib_paths; if( query_load_prefer(interp) ) load_prefer = PREFER_SOURCE; /* create lib_paths, a fixed array of hashes. The array indexing is for the loader types. The elements of the array are a hash implementing a "interpreter" name-space. */ lib_paths = pmc_new(interp, enum_class_Hash); populate_builtin_library_paths(interp, lib_paths); iglobals = interp->iglobals; VTABLE_set_pmc_keyed_int(interp, iglobals, IGLOBALS_LIB_PATHS, lib_paths); } static STRING* load_trace; /* used to accumulate a trace of a load for diagnostics & debugging */ #define TRACE_ENABLED ( NULL != load_trace ) #define SET_TRACE( trace ) { load_trace = trace; } static void append_trace (Interp* interp, const char* const format, ... ) { STRING* format_string = string_from_cstring( format ); va_list args; va_start(args, format); string_append(interp, load_trace, Parrot_sprintf_s(interp, format, args); va_end(args); } #define SEARCH_TRACE_PSTRING ( format , args... )\ {\ if( NULL != search_trace ) {\ string_append(interp,load_trace,\ append_trace(interp,format, ## args ));\ }\ } #define SEARCH_TRACE_CSTRING ( format , args... )\ {\ if ( NULL != load_trace ) {\ string_append(interp, load_trace,\ string_printf( format , ## args );\ }\ } static PMC* namespace_search_path(Interp *interp, STRING* hll, enum_runtime_ft loader, enum_search_space search_space) { PMC *iglobals, *lib_paths, *loader_table, *search_table; iglobals = interp->iglobals; lib_paths = VTABLE_get_pmc_keyed_int(interp, iglobals, IGLOBALS_LIB_PATHS); /* first do the namespace lookup to find the loader table */ if ( ! VTABLE_exists_keyed_str(interp, lib_paths, hll) ) return NULL; loader_table = VTABLE_get_pmc_keyed_str(interp, lib_paths, hll ); /* second look for a entry matching the loader desired */ if ( ! VTABLE_exists_keyed_int(interp, loader_table, loader) ) return NULL; search_table = VTABLE_get_pmc_keyed_int(interp, loader_table, loader ); /* check for the the PATH or EXT search table */ if ( ! VTABLE_exists_keyed_int(interp, search_table, search_space) ) return NULL; return VTABLE_get_pmc_keyed_int(interp, search_table, search_space ); } /* implement search space lookup , with a hard-coded default namespace * for fallback */ static PMC* get_search_space(Interp *interp, STRING* hll, enum_runtime_ft loader, enum_search_space search_space) { PMC *table; if ( NULL == hll ) goto fallback; table = namespace_search_path(interp, hll, loader, search_space ); if ( NULL == table ) { fallback: hll = CONST_STRING(interp, "parrot" ); table = namespace_search_path(interp, hll, loader, search_space); } return table; } #include "path.c" static STRING* verify_load_path(Interp *interp, STRING* path) { STRING *final; final = string_copy(interp, path); #ifdef DEBUG_LIB_LOADER printf("path is \"%s\"\n", string_to_cstring(interp, final )); #endif final = parrot_path_platform_localize(interp, final ); if (Parrot_stat_info_intval(interp, final , STAT_EXISTS)) { return final; } return NULL; } /* * find the best format for the module */ static STRING* try_extensions( Interp *interp, PMC* search_space , STRING* path ) { STRING *with_ext, *result, *ext; int i,n; /* * first try the path without guessing to ensure compatibility with * existing code. */ with_ext = string_copy(interp, path); if ( (result = verify_load_path(interp, with_ext)) ) return result; n = VTABLE_elements(interp, search_space); bound_by_load_prefer(&i, &n); while( i != n ) { with_ext = string_copy(interp, path); with_ext = string_append(interp, with_ext, VTABLE_get_string_keyed_int(interp, search_space, i)); if ( (result = verify_load_path(interp, with_ext)) ) return result; i = next_by_load_prefer(i); } return NULL; } /* try_path: implements search-rule 1 * * First try a path as formed, then perform extension guessing. */ static STRING* try_path(interp, PMC* ext_srch_space , STRING* path ) { STRING* result = NULL; if ( result = verify_load_path(interp, path) ) return result; return ( NULL == ext_srch_space ) ? NULL : try_extensions(interp, ext_src_space, path); } /* =item C<char* Parrot_locate_runtime_file(Interp *, const char *object_name, STRING *hll enum_runtime_ft *loader STRING* trace)> Parrot_locate_runtime_str searches the filesystem for object files containing code of some sort. This function is required by several opcodes/components and is designed with parrot's unusual flexiblity in mind. object_name : the name of the object to load. It can be simply a name, path, or absolute path. hll : The hll argument is the key to the HLL name-space. The default namespace is used if the namespace does not exist or is null. The default name-space is "parrot". loader : a bit-mask selecting loaders to be included in the search. This arguement is passed by reference. When a matching file is found the value of loader is reset to the flag for the loader under which it was found. loader is not modified unless a matching file is found. trace : given non-null string a trace of the search will be appended. This allows higher level API's to capture detailed diagnostics when the search fails. This is useful for all parties. The return value is: * a string containing the path to the objects preferred form, or NULL if not found. * localized with parrot_platform_path_localize * all path seperators are coverted to the platform's value (ie Win32) * a hidden 0 char is appended making it suitable for direct use in C API calls, an artifact of the previous implementation. Search behavior: code objects can have several formats, some of which will be stored on disk. This routine searches for the preferred format of an object. Preferred is either lowest form (compiled), or highest form (source). The given search rules apply at each step in the search order. The search order is executed per loader. The loader mask is also traversed in preferred the order. rule 1: parrot will always try the object_name as given before adding extensions. The set of extensions tried is loader specific. Search order: 1. Absolute paths (return or fail) 2. Search the paths joined with get_runtime_prefix 3. joined with get_runtime_prefix 4. as given Exception 1. absolute paths in the path list are not prefixed Exception 2. If the loader mask is zero: step two of the search order will be skipped. extensions are skipped since there is no loader information available. The two modals for the search are the runtime_prefix and preferred order. SEE ALSO: Parrot_get_runtime_prefix, query_load_prefer , F<include/parrot/library.h> current parrot behavior can be achieved by passing NULL as the hll argument, and a loader mask of: PARROT_RUNTIME_FT_BYTECODE & PARROT_RUNTIME_FT_INCLUDE & PARROT_RUNTIME_FT_SOURCE for parrot bytecode, and PARROT_RUNTIME_FT_ARCH for platform shared objects. Implementation Notes: The implementation of the search behavior is tagged in this file. rules : grep search-rule x search order : grep search-order x search exception : grep search-rule x The search lists for both paths and extensions are dynamic arrays. In the extension search space it is assumed that the lowest index corresponds to the lowest form, and that the array is sorted accordingly. TODO: the extension , which is actually the stage of interpretation contained by the format is returned in the extension of the file. This should be returned as a optimization hint to heuristics that do the real determination of what's in a file , ( example: use v6; or shebang invocations ) TODO: instead of a string that is checked by stat() , a handle should be returned instead to close the classic access() race. Additional flags are needed for that such as NO_TTY and other basic cross-platform security open() masks. <-- huge warning. (This should be relative to a loader , higher level forms may have looser security constraints) TODO: OS IO/VM hinting. some loaders could benefit from IO hinting such as mapped/streamed, use-once etc. depends on returning a handle and open flags. =cut */ /* compute a bit-flag from a index of the loader bits. Need to check endian issues */ static int ft_index_to_mask (int index ) { return 1 << index; } /* we have a multi-value return. Ensure that code does not forget to * set one of the expected returns by encapsulating return value * construction in a macro */ #define return_if_found ( path , for_loader ) if( path ) { *loader = for_loader ; return path } STRING* Parrot_locate_runtime_file_str(Interp *interp, STRING *object_name, STRING *hll, enum_runtime_ft *loader, STRING* trace) { STRING *prefix, *full_name; int l_idx, l_bound; PMC *path_srch_space, *ext_search; /* set the static trace variable, NULL to disable or a string for the diagnostics data. */ SET_TRACE( trace ); SEARCH_TRACE_PSTRING( "looking up path for object: %s\n" , object_name ); /* get the value of PARROT_RUNTIME if any, a constant for the paths below */ prefix = Parrot_get_runtime_prefix(interp); if( TRACE_ENABLED && prefix && string_length(interp, prefix)) append_trace(interp, "prefix is set as %s\n",prefix); /* If it is an absolute path try it now. If it fails skip the rest of the search for this loader */ if ( !*loader ) SEARCH_TRACE_CSTRING( "all loaders disabled, path search disabled\n" ); if ( !parrot_path_is_abs(interp, object_name) ) { full_name = try_path(interp, NULL, path_concat(interp, prefix, object_name)); return_if_found( full_name , 0 ); } full_name = try_path(interp, NULL, object_name); return_if_found( full_name , 0 ); return NULL; } l_bound = PARROT_RUNTIME_FT_SIZE; bound_by_load_prefer(&l_idx, &l_bound); while( l_idx != l_bound ) { int p_idx, p_bound; /* ingore loaders not in the mask */ if (0 == (ft_index_to_mask(l_idx) & *loader)) { l_idx = next_by_load_prefer(l_idx); continue; } SEARCH_TRACE_CSTRING( "looking in paths for loader %s\n", loader_names[l_idx] ); /* we should always get a search space unless the "parrot" search space is broken in the tree */ path_srch_space = get_search_space(interp, hll, *loader , SEARCH_TABLE_PATH ); ext_srch_space = get_search_space(interp, hll, *loader , SEARCH_TABLE_EXT ); assert(path_srch_space); assert(ext_srch_space); /* If it is an absolute path try it now. If it fails skip the rest of the search for this loader */ if (parrot_path_is_abs(interp, object_name)) { full_name = try_path(interp, ext_src_space, object_name); return_if_found( full_name , ft_index_to_mask(l_idx) ); l_idx = next_by_load_prefer(l_idx); continue; } /* now iterate through the paths , incorperating the value * of PARROT_RUNTIME as well */ p_bound = VTABLE_elements(interp, path_srch_space); bound_by_load_prefer(&p_idx, &p_bound); while( p_idx != p_bound ) { STRING *path = VTABLE_get_string_keyed_int(interp, path, p_idx); /* search-exception 1 */ full_name = ( prefix && string_length(interp, prefix) && !parrot_path_is_abs(interp,path)) ? parrot_path_concat(interp, prefix , path) : string_copy(interp, path); /* search-order 2 */ full_name = try_path(interp, ext_srch_space, parrot_path_append(interp, full_name , object_name)); return_if_found( full_name , ft_index_to_mask(l_idx) ); p_idx = next_by_load_prefer(p_idx); } /* search-order 3 */ if ( prefix && string_length(interp, prefix) ) { full_name = try_path(interp, ext_srch_space, parrot_path_concat(interp, prefix , object_name)); return_if_found( full_name , ft_index_to_mask(l_idx) ); } /* search-order 4 */ full_name = try_path(interp, ext_srch_space, object_name); return_if_found( full_name , ft_index_to_mask(l_idx) ); l_idx = next_by_load_prefer(l_idx); } return NULL; } static STRING* query_runtime_prefix ( Interp* interp ) { STRING* prefix; int free_it; char *env; env = Parrot_getenv("PARROT_RUNTIME", &free_it); if (env) { prefix = string_from_cstring(interp, env, 0); if (free_it) mem_sys_free(env); return prefix; } return NULL; } /* =item C<STRING* Parrot_get_runtime_prefix(Interp * )> return the runtime prefix in the PMC string C<prefix>. The config hash is used first if given, then the value of the environment variable PARROT_RUNTIME. If neither are found NULL is returned. =cut */ STRING* Parrot_get_runtime_prefix (Interp *interp ) { PMC *config_hash; STRING *key, *can_fail; /* can_fail , for storing string pointers from functions that may fail to return a prefix value */ /* first look in the config hash for a user specified path */ config_hash = VTABLE_get_pmc_keyed_int(interp, interp->iglobals, (INTVAL) IGLOBALS_CONFIG_HASH); if (VTABLE_elements(interp, config_hash)) { key = CONST_STRING(interp, "prefix"); can_fail = VTABLE_get_string_keyed_str(interp, config_hash, key); if ( can_fail ) { /* TODO: shouldn't we do some sanity here ? , assuming this can be set by random code/input we should see if it even exists. */ return can_fail; } } /* fallback: no value was found in the config hash so try a system query, if that fails as well return the default. */ return query_runtime_prefix(interp); } /* =back =head1 SEE ALSO F<include/parrot/library.h> =cut */ /* * Local variables: * c-file-style: "parrot" * End: * vim: expandtab shiftwidth=4: */
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