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Diffstat (limited to 'tex/context/base/mkiv/util-lib.lua')
| -rw-r--r-- | tex/context/base/mkiv/util-lib.lua | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/tex/context/base/mkiv/util-lib.lua b/tex/context/base/mkiv/util-lib.lua new file mode 100644 index 000000000..2601b2e57 --- /dev/null +++ b/tex/context/base/mkiv/util-lib.lua @@ -0,0 +1,297 @@ +if not modules then modules = { } end modules ['util-lib'] = { + version = 1.001, + comment = "companion to luat-lib.mkiv", + author = "Hans Hagen, PRAGMA-ADE, Hasselt NL", + copyright = "PRAGMA ADE / ConTeXt Development Team", + license = "see context related readme files", +} + +-- This is experimental code for Hans and Luigi. Don't depend on it! There +-- will be a plain variant. + +--[[ + +The problem with library bindings is manyfold. They are of course platform +dependent and while a binary with its directly related libraries are often +easy to maintain and load, additional libraries can each have their demands. + +One important aspect is that loading additional libraries from within the +loaded one is also operating system dependent. There can be shared libraries +elsewhere on the system and as there can be multiple libraries with the same +name but different usage and versioning there can be clashes. So there has to +be some logic in where to look for these sublibraries. + +We found out that for instance on windows libraries are by default sought on +the parents path and then on the binary paths and these of course can be in +an out of our control, thereby enlarging the changes on a clash. A rather +safe solution for that to load the library on the path where it sits. + +Another aspect is initialization. When you ask for a library t.e.x it will +try to initialize luaopen_t_e_x no matter if such an inializer is present. +However, because loading is configurable and in the case of luatex is already +partly under out control, this is easy to deal with. We only have to make +sure that we inform the loader that the library has been loaded so that +it won't load it twice. + +In swiglib we have chosen for a clear organization and although one can use +variants normally in the tex directory structure predictability is more or +less the standard. For instance: + +.../tex/texmf-mswin/bin/lib/luatex/lua/swiglib/mysql/core.dll +.../tex/texmf-mswin/bin/lib/luajittex/lua/swiglib/mysql/core.dll +.../tex/texmf-mswin/bin/lib/luatex/context/lua/swiglib/mysql/core.dll +.../tex/texmf-mswin/bin/lib/swiglib/lua/mysql/core.dll +.../tex/texmf-mswin/bin/lib/swiglib/lua/mysql/5.6/core.dll + +The lookups are determined via an entry in texmfcnf.lua: + +CLUAINPUTS = ".;$SELFAUTOLOC/lib/{$engine,luatex}/lua//", + +A request for t.e.x is converted to t/e/x.dll or t/e/x.so depending on the +platform. Then we use the regular finder to locate the file in the tex +directory structure. Once located we goto the path where it sits, load the +file and return to the original path. We register as t.e.x in order to +prevent reloading and also because the base name is seldom unique. + +The main function is a big one and evolved out of experiments that Luigi +Scarso and I conducted when playing with variants of SwigLib. The function +locates the library using the context mkiv resolver that operates on the +tds tree and if that doesn't work out well, the normal clib path is used. + +The lookups is somewhat clever in the sense that it can deal with (optional) +versions and can fall back on non versioned alternatives if needed, either +or not using a wildcard lookup. + +This code is experimental and by providing a special abstract loader (called +swiglib) we can start using the libraries. + +A complication is that we might end up with a luajittex path matching before a +luatex path due to the path spec. One solution is to first check with the engine +prefixed. This could be prevented by a more strict lib pattern but that is not +always under our control. So, we first check for paths with engine in their name +and then without. + +]]-- + +-- seems to be clua in recent texlive + +local gsub, find = string.gsub, string.find +local pathpart, nameonly, joinfile = file.pathpart, file.nameonly, file.join +local findfile, findfiles = resolvers and resolvers.findfile, resolvers and resolvers.findfiles + +local loaded = package.loaded + +local report_swiglib = logs.reporter("swiglib") +local trace_swiglib = false trackers.register("resolvers.swiglib", function(v) trace_swiglib = v end) + +-- We can check if there are more that one component, and if not, we can +-- append 'core'. + +local done = false + +local function requireswiglib(required,version) + local trace_swiglib = trace_swiglib or package.helpers.trace + local library = loaded[required] + if library == nil then + if trace_swiglib then + report_swiglib("requiring library %a with version %a",required,version or "any") + end + -- initialize a few variables + local required_full = gsub(required,"%.","/") -- package.helpers.lualibfile + local required_path = pathpart(required_full) + local required_base = nameonly(required_full) + local required_name = required_base .. "." .. os.libsuffix + local version = type(version) == "string" and version ~= "" and version or false + local engine = environment.ownmain or false + -- + if trace_swiglib and not done then + local list = resolvers.expandedpathlistfromvariable("lib") -- fresh, no reuse + for i=1,#list do + report_swiglib("tds path %i: %s",i,list[i]) + end + end + -- helpers + local function found(locate,asked_library,how,...) + if trace_swiglib then + report_swiglib("checking %s: %a",how,asked_library) + end + return locate(asked_library,...) + end + local function check(locate,...) + local found = nil + if version then + local asked_library = joinfile(required_path,version,required_name) + if trace_swiglib then + report_swiglib("checking %s: %a","with version",asked_library) + end + found = locate(asked_library,...) + end + if not found or found == "" then + local asked_library = joinfile(required_path,required_name) + if trace_swiglib then + report_swiglib("checking %s: %a","with version",asked_library) + end + found = locate(asked_library,...) + end + return found and found ~= "" and found or false + end + -- Alternatively we could first collect the locations and then do the two attempts + -- on this list but in practice this is not more efficient as we might have a fast + -- match anyway. + local function attempt(checkpattern) + -- check cnf spec using name and version + if trace_swiglib then + report_swiglib("checking tds lib paths strictly") + end + local found = findfile and check(findfile,"lib") + if found and (not checkpattern or find(found,checkpattern)) then + return found + end + -- check cnf spec using wildcard + if trace_swiglib then + report_swiglib("checking tds lib paths with wildcard") + end + local asked_library = joinfile(required_path,".*",required_name) + if trace_swiglib then + report_swiglib("checking %s: %a","latest version",asked_library) + end + local list = findfiles(asked_library,"lib",true) + if list and #list > 0 then + table.sort(list) + local found = list[#list] + if found and (not checkpattern or find(found,checkpattern)) then + return found + end + end + -- Check lib paths using name and version. + if trace_swiglib then + report_swiglib("checking lib paths") + end + package.extralibpath(environment.ownpath) + local paths = package.libpaths() + for i=1,#paths do + local found = check(lfs.isfile) + if found and (not checkpattern or find(found,checkpattern)) then + return found + end + end + return false + end + local found_library = nil + if engine then + if trace_swiglib then + report_swiglib("attemp 1, engine %a",engine) + end + found_library = attempt("/"..engine.."/") + if not found_library then + if trace_swiglib then + report_swiglib("attemp 2, no engine",asked_library) + end + found_library = attempt() + end + else + found_library = attempt() + end + -- load and initialize when found + if not found_library then + if trace_swiglib then + report_swiglib("not found: %a",required) + end + library = false + else + local path = pathpart(found_library) + local base = nameonly(found_library) + dir.push(path) + if trace_swiglib then + report_swiglib("found: %a",found_library) + end + local message = nil + local opener = "luaopen_" .. required_base + library, message = package.loadlib(found_library,opener) + local libtype = type(library) + if libtype == "function" then + library = library() + else + report_swiglib("load error: %a returns %a, message %a, library %a",opener,libtype,(string.gsub(message or "no message","[%s]+$","")),found_library or "no library") + library = false + end + dir.pop() + end + -- cache result + if not library then + report_swiglib("unknown: %a",required) + elseif trace_swiglib then + report_swiglib("stored: %a",required) + end + loaded[required] = library + else + report_swiglib("reused: %a",required) + end + return library +end + +--[[ + +For convenience we make the require loader function swiglib aware. Alternatively +we could put the specific loader in the global namespace. + +]]-- + +local savedrequire = require + +function require(name,version) + if find(name,"^swiglib%.") then + return requireswiglib(name,version) + else + return savedrequire(name) + end +end + +--[[ + +At the cost of some overhead we provide a specific loader so that we can keep +track of swiglib usage which is handy for development. In context this is the +recommended loader. + +]]-- + +local swiglibs = { } +local initializer = "core" + +function swiglib(name,version) + local library = swiglibs[name] + if not library then + statistics.starttiming(swiglibs) + if trace_swiglib then + report_swiglib("loading %a",name) + end + if not find(name,"%." .. initializer .. "$") then + fullname = "swiglib." .. name .. "." .. initializer + else + fullname = "swiglib." .. name + end + library = requireswiglib(fullname,version) + swiglibs[name] = library + statistics.stoptiming(swiglibs) + end + return library +end + +statistics.register("used swiglibs", function() + if next(swiglibs) then + return string.format("%s, initial load time %s seconds",table.concat(table.sortedkeys(swiglibs)," "),statistics.elapsedtime(swiglibs)) + end +end) + +--[[ + +So, we now have: + +local gm = require("swiglib.gmwand.core") +local gm = swiglib("gmwand.core") +local sq = swiglib("mysql.core") +local sq = swiglib("mysql.core","5.6") + +Watch out, the last one is less explicit and lacks the swiglib prefix. + +]]-- |