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diff --git a/src/rlx_depsolver.erl b/src/rlx_depsolver.erl new file mode 100644 index 0000000..0cf8c88 --- /dev/null +++ b/src/rlx_depsolver.erl @@ -0,0 +1,718 @@ +%% -*- erlang-indent-level: 4; indent-tabs-mode: nil; fill-column: 80 -*- +%% ex: ts=4 sx=4 et +%% +%% Copyright 2012 Opscode, Inc. All Rights Reserved. +%% +%% This file is provided to you under the Apache License, +%% Version 2.0 (the "License"); you may not use this file +%% except in compliance with the License. You may obtain +%% a copy of the License at +%% +%% http://www.apache.org/licenses/LICENSE-2.0 +%% +%% Unless required by applicable law or agreed to in writing, +%% software distributed under the License is distributed on an +%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +%% KIND, either express or implied. See the License for the +%% specific language governing permissions and limitations +%% under the License. +%% +%% @author Eric Merritt <[email protected]> +%% +%%%------------------------------------------------------------------- +%%% @doc +%%% This is a dependency constraint solver. You add your 'world' to the +%%% solver. That is the packages that exist, their versions and their +%%% dependencies. Then give the system a set of targets and ask it to solve. +%%% +%%% Lets say our world looks as follows +%%% +%%% app1 that has versions "0.1" +%%% depends on app3 any version greater then "0.2" +%%% "0.2" with no dependencies +%%% "0.3" with no dependencies +%%% +%%% app2 that has versions "0.1" with no dependencies +%%% "0.2" that depends on app3 exactly "0.3" +%%% "0.3" with no dependencies +%%% +%%% app3 that has versions +%%% "0.1", "0.2" and "0.3" all with no dependencies +%%% +%%% we can add this world to the system all at once as follows +%%% +%%% Graph0 = rcl_depsolver:new_graph(), +%%% Graph1 = rcl_depsolver:add_packages( +%%% [{app1, [{"0.1", [{app2, "0.2"}, +%%% {app3, "0.2", '>='}]}, +%%% {"0.2", []}, +%%% {"0.3", []}]}, +%%% {app2, [{"0.1", []}, +%%% {"0.2",[{app3, "0.3"}]}, +%%% {"0.3", []}]}, +%%% {app3, [{"0.1", []}, +%%% {"0.2", []}, +%%% {"0.3", []}]}]). +%%% +%%% We can also build it up incrementally using the other add_package and +%%% add_package_version functions. +%%% +%%% Finally, once we have built up the graph we can ask rcl_depsolver to solve the +%%% dependency constraints. That is to give us a list of valid dependencies by +%%% using the solve function. Lets say we want the app3 version "0.3" and all of +%%% its resolved dependencies. We could call solve as follows. +%%% +%%% rcl_depsolver:solve(Graph1, [{app3, "0.3"}]). +%%% +%%% That will give us the completely resolved dependencies including app3 +%%% itself. Lets be a little more flexible. Lets ask for a graph that is rooted +%%% in anything greater then or equal to app3 "0.3". We could do that by +%%% +%%% rcl_depsolver:solve(Graph1, [{app3, "0.3", '>='}]). +%%% +%%% Of course, you can specify any number of goals at the top level. +%%% @end +%%%------------------------------------------------------------------- +-module(rcl_depsolver). + +%% Public Api +-export([format_error/1, + format_roots/1, + format_culprits/1, + format_constraint/1, + format_version/1, + new_graph/0, + solve/2, + add_packages/2, + add_package/3, + add_package_version/3, + add_package_version/4, + parse_version/1, + is_valid_constraint/1, + filter_packages/2]). + +%% Internally Exported API. This should *not* be used outside of the rcl_depsolver +%% application. You have been warned. +-export([dep_pkg/1, + filter_package/2, + primitive_solve/3]). + +-export_type([t/0, + pkg/0, + constraint_op/0, + pkg_name/0, + vsn/0, + constraint/0, + dependency_set/0]). + +-export_type([dep_graph/0, constraints/0, + ordered_constraints/0, fail_info/0, + fail_detail/0]). +%%============================================================================ +%% type +%%============================================================================ +-type dep_graph() :: gb_tree(). +-opaque t() :: {?MODULE, dep_graph()}. +-type pkg() :: {pkg_name(), vsn()}. +-type pkg_name() :: binary() | atom(). +-type raw_vsn() :: ec_semver:any_version(). + +-type vsn() :: 'NO_VSN' + | ec_semver:semver(). + +-type constraint_op() :: + '=' | gte | '>=' | lte | '<=' + | gt | '>' | lt | '<' | pes | '~>' | between. + +-type raw_constraint() :: pkg_name() + | {pkg_name(), raw_vsn()} + | {pkg_name(), raw_vsn(), constraint_op()} + | {pkg_name(), raw_vsn(), vsn(), between}. + +-type constraint() :: pkg_name() + | {pkg_name(), vsn()} + | {pkg_name(), vsn(), constraint_op()} + | {pkg_name(), vsn(), vsn(), between}. + + +-type vsn_constraint() :: {raw_vsn(), [raw_constraint()]}. +-type dependency_set() :: {pkg_name(), [vsn_constraint()]}. + +%% Internal Types +-type constraints() :: [constraint()]. +-type ordered_constraints() :: [{pkg_name(), constraints()}]. +-type fail_info() :: {[pkg()], ordered_constraints()}. +-type fail_detail() :: {fail, [fail_info()]}. +-type version_checker() :: fun((vsn()) -> fail_detail() | vsn()). + +%%============================================================================ +%% API +%%============================================================================ +%% @doc create a new empty dependency graph +-spec new_graph() -> t(). +new_graph() -> + {?MODULE, gb_trees:empty()}. + +%% @doc add a complete set of list of packages to the graph. Where the package +%% consists of the name and a list of versions and dependencies. +%% +%% ``` rcl_depsolver:add_packages(Graph, +%% [{app1, [{"0.1", [{app2, "0.2"}, +%% {app3, "0.2", '>='}]}, +%% {"0.2", []}, +%% {"0.3", []}]}, +%% {app2, [{"0.1", []}, +%% {"0.2",[{app3, "0.3"}]}, +%% {"0.3", []}]}, +%% {app3, [{"0.1", []}, +%% {"0.2", []}, +%% {"0.3", []}]}]) +%% ''' +-spec add_packages(t(),[dependency_set()]) -> t(). +add_packages(Dom0, Info) + when is_list(Info) -> + lists:foldl(fun({Pkg, VsnInfo}, Dom1) -> + add_package(Dom1, Pkg, VsnInfo) + end, Dom0, Info). + +%% @doc add a single package to the graph, where it consists of a package name +%% and its versions and thier dependencies. +%% ```rcl_depsolver:add_package(Graph, app1, [{"0.1", [{app2, "0.2"}, +%% {app3, "0.2", '>='}]}, +%% {"0.2", []}, +%% {"0.3", []}]}]). +%% ''' +-spec add_package(t(),pkg_name(),[vsn_constraint()]) -> t(). +add_package(State, Pkg, Versions) + when is_list(Versions) -> + lists:foldl(fun({Vsn, Constraints}, Dom1) -> + add_package_version(Dom1, Pkg, Vsn, Constraints); + (Version, Dom1) -> + add_package_version(Dom1, Pkg, Version, []) + end, State, Versions). + +%% @doc add a set of dependencies to a specific package and version. +%% and its versions and thier dependencies. +%% ```rcl_depsolver:add_package(Graph, app1, "0.1", [{app2, "0.2"}, +%% {app3, "0.2", '>='}]}, +%% {"0.2", []}, +%% {"0.3", []}]). +%% ''' +-spec add_package_version(t(), pkg_name(), raw_vsn(), [raw_constraint()]) -> t(). +add_package_version({?MODULE, Dom0}, RawPkg, RawVsn, RawPkgConstraints) -> + Pkg = fix_pkg(RawPkg), + Vsn = parse_version(RawVsn), + %% Incoming constraints are raw + %% and need to be fixed + PkgConstraints = [fix_con(PkgConstraint) || + PkgConstraint <- RawPkgConstraints], + Info2 = + case gb_trees:lookup(Pkg, Dom0) of + {value, Info0} -> + case lists:keytake(Vsn, 1, Info0) of + {value, {Vsn, Constraints}, Info1} -> + [{Vsn, join_constraints(Constraints, + PkgConstraints)} + | Info1]; + false -> + [{Vsn, PkgConstraints} | Info0] + end; + none -> + [{Vsn, PkgConstraints}] + end, + {?MODULE, gb_trees:enter(Pkg, Info2, Dom0)}. + +%% @doc add a package and version to the dependency graph with no dependency +%% constraints, dependency constraints can always be added after the fact. +%% +%% ```rcl_depsolver:add_package_version(Graph, app1, "0.1").''' +-spec add_package_version(t(),pkg_name(),raw_vsn()) -> t(). +add_package_version(State, Pkg, Vsn) -> + add_package_version(State, Pkg, Vsn, []). + +%% @doc Given a set of goals (in the form of constrains) find a set of packages +%% and versions that satisfy all constraints. If no solution can be found then +%% an exception is thrown. +%% ``` rcl_depsolver:solve(State, [{app1, "0.1", '>='}]).''' +-spec solve(t(),[constraint()]) -> {ok, [pkg()]} | {error, term()}. +solve({?MODULE, DepGraph0}, RawGoals) + when erlang:length(RawGoals) > 0 -> + Goals = [fix_con(Goal) || Goal <- RawGoals], + case trim_unreachable_packages(DepGraph0, Goals) of + Error = {error, _} -> + Error; + DepGraph1 -> + case primitive_solve(DepGraph1, Goals, no_path) of + {fail, _} -> + [FirstCons | Rest] = Goals, + {error, rcl_depsolver_culprit:search(DepGraph1, [FirstCons], Rest)}; + Solution -> + {ok, Solution} + end + end. + +%% @doc Parse a string version into a tuple based version +-spec parse_version(raw_vsn() | vsn()) -> vsn(). +parse_version(RawVsn) + when erlang:is_list(RawVsn); + erlang:is_binary(RawVsn) -> + ec_semver:parse(RawVsn); +parse_version(Vsn) + when erlang:is_tuple(Vsn) -> + Vsn. + +%% @doc check that a specified constraint is a valid constraint. +-spec is_valid_constraint(constraint()) -> boolean(). +is_valid_constraint(Pkg) when is_atom(Pkg) orelse is_binary(Pkg) -> + true; +is_valid_constraint({_Pkg, Vsn}) when is_tuple(Vsn) -> + true; +is_valid_constraint({_Pkg, Vsn, '='}) when is_tuple(Vsn) -> + true; +is_valid_constraint({_Pkg, _LVsn, gte}) -> + true; +is_valid_constraint({_Pkg, _LVsn, '>='}) -> + true; +is_valid_constraint({_Pkg, _LVsn, lte}) -> + true; +is_valid_constraint({_Pkg, _LVsn, '<='}) -> + true; +is_valid_constraint({_Pkg, _LVsn, gt}) -> + true; +is_valid_constraint({_Pkg, _LVsn, '>'}) -> + true; +is_valid_constraint({_Pkg, _LVsn, lt}) -> + true; +is_valid_constraint({_Pkg, _LVsn, '<'}) -> + true; +is_valid_constraint({_Pkg, _LVsn, pes}) -> + true; +is_valid_constraint({_Pkg, _LVsn, '~>'}) -> + true; +is_valid_constraint({_Pkg, _LVsn1, _LVsn2, between}) -> + true; +is_valid_constraint(_InvalidConstraint) -> + false. + + +%% @doc given a list of package name version pairs, and a list of constraints +%% return every member of that list that matches all constraints. +-spec filter_packages([{pkg_name(), raw_vsn()}], [raw_constraint()]) -> + {ok, [{pkg_name(), raw_vsn()}]} + | {error, Reason::term()}. +filter_packages(PVPairs, RawConstraints) -> + Constraints = [fix_con(Constraint) || Constraint <- RawConstraints], + case check_constraints(Constraints) of + ok -> + {ok, [PVPair || PVPair <- PVPairs, + filter_pvpair_by_constraint(fix_con(PVPair), Constraints)]}; + Error -> + Error + end. + +%% @doc Produce a full error message for a given error condition. This includes +%% details of the paths taken to resolve the dependencies and shows which dependencies +%% could not be satisfied +-spec format_error({error, {unreachable_package, list()} | + {invalid_constraints, [constraint()]} | + list()}) -> iolist(). +format_error(Error) -> + rcl_depsolver_culprit:format_error(Error). + +%% @doc Return a formatted list of roots of the dependency trees which +%% could not be satisified. These may also have versions attached. +%% Example: +%% +%% ```(foo = 1.2.0), bar``` +%% +-spec format_roots([constraints()]) -> iolist(). +format_roots(Roots) -> + rcl_depsolver_culprit:format_roots(Roots). + + +%% @doc Return a formatted list of the culprit depenedencies which led to +%% the dependencies not being satisfied. Example: +%% +%% ```(foo = 1.2.0) -> (bar > 2.0.0)``` +-spec format_culprits([{[constraint()], [constraint()]}]) -> iolist(). +format_culprits(Culprits) -> + rcl_depsolver_culprit:format_culprits(Culprits). + +%% @doc A formatted version tuple +-spec format_version(vsn()) -> iolist(). +format_version(Version) -> + rcl_depsolver_culprit:format_version(Version). + +%% @doc A formatted constraint tuple +-spec format_constraint(constraint()) -> iolist(). +format_constraint(Constraint) -> + rcl_depsolver_culprit:format_constraint(Constraint). + +%%==================================================================== +%% Internal Functions +%%==================================================================== +-spec check_constraints(constraints()) -> + ok | {error, {invalid_constraints, [term()]}}. +check_constraints(Constraints) -> + PossibleInvalids = + lists:foldl(fun(Constraint, InvalidConstraints) -> + case is_valid_constraint(Constraint) of + true -> + InvalidConstraints; + false -> + [Constraint | InvalidConstraints] + end + end, [], Constraints), + case PossibleInvalids of + [] -> + ok; + _ -> + {error, {invalid_constraints, PossibleInvalids}} + end. + + +-spec filter_pvpair_by_constraint({pkg_name(), vsn()}, [constraint()]) -> + boolean(). +filter_pvpair_by_constraint(PVPair, Constraints) -> + lists:all(fun(Constraint) -> + filter_package(PVPair, Constraint) + end, Constraints). + +-spec filter_package({pkg_name(), vsn()}, constraint()) -> + boolean(). +filter_package({PkgName, Vsn}, C = {PkgName, _}) -> + is_version_within_constraint(Vsn, C); +filter_package({PkgName, Vsn}, C = {PkgName, _, _}) -> + is_version_within_constraint(Vsn, C); +filter_package({PkgName, Vsn}, C = {PkgName, _, _, _}) -> + is_version_within_constraint(Vsn, C); +filter_package(_, _) -> + %% If its not explicitly excluded its included + true. + +%% @doc +%% fix the package name. If its a list turn it into a binary otherwise leave it as an atom +fix_pkg(Pkg) when is_list(Pkg) -> + erlang:list_to_binary(Pkg); +fix_pkg(Pkg) when is_binary(Pkg); is_atom(Pkg) -> + Pkg. + +%% @doc +%% fix package. Take a package with a possible invalid version and fix it. +-spec fix_con(raw_constraint()) -> constraint(). +fix_con({Pkg, Vsn}) -> + {fix_pkg(Pkg), parse_version(Vsn)}; +fix_con({Pkg, Vsn, CI}) -> + {fix_pkg(Pkg), parse_version(Vsn), CI}; +fix_con({Pkg, Vsn1, Vsn2, CI}) -> + {fix_pkg(Pkg), parse_version(Vsn1), + parse_version(Vsn2), CI}; +fix_con(Pkg) -> + fix_pkg(Pkg). + + +%% @doc given two lists of constraints join them in such a way that no +%% constraint is duplicated but the over all order of the constraints is +%% preserved. Order drives priority in this solver and is important for that +%% reason. +-spec join_constraints([constraint()], [constraint()]) -> + [constraint()]. +join_constraints(NewConstraints, ExistingConstraints) -> + ECSet = sets:from_list(ExistingConstraints), + FilteredNewConstraints = [NC || NC <- NewConstraints, + not sets:is_element(NC, ECSet)], + ExistingConstraints ++ FilteredNewConstraints. + + +%% @doc constraints is an associated list keeping track of all the constraints +%% that have been placed on a package +-spec new_constraints() -> constraints(). +new_constraints() -> + []. + +%% @doc Given a dep graph and a set of goals this either solves the problem or +%% fails. This is basically the root solver of the system, the main difference +%% from the exported solve/2 function is the fact that this does not do the +%% culprit search. +-spec primitive_solve(dep_graph(),[constraint()], term()) -> + [pkg()] | fail_detail(). +primitive_solve(State, PackageList, PathInd) + when erlang:length(PackageList) > 0 -> + Constraints = lists:foldl(fun(Info, Acc) -> + add_constraint('_GOAL_', 'NO_VSN', Acc, Info) + end, new_constraints(), PackageList), + + Pkgs = lists:map(fun dep_pkg/1, PackageList), + all_pkgs(State, [], Pkgs, Constraints, PathInd). + +%% @doc +%% given a Pkg | {Pkg, Vsn} | {Pkg, Vsn, Constraint} return Pkg +-spec dep_pkg(constraint()) -> pkg_name(). +dep_pkg({Pkg, _Vsn}) -> + Pkg; +dep_pkg({Pkg, _Vsn, _}) -> + Pkg; +dep_pkg({Pkg, _Vsn1, _Vsn2, _}) -> + Pkg; +dep_pkg(Pkg) when is_atom(Pkg) orelse is_binary(Pkg) -> + Pkg. + +-spec add_constraint(pkg_name(), vsn(), [constraint()],constraint()) -> ordered_constraints(). +add_constraint(SrcPkg, SrcVsn, PkgsConstraints, PkgConstraint) -> + case is_valid_constraint(PkgConstraint) of + true -> ok; + false -> erlang:throw({invalid_constraint, PkgConstraint}) + end, + PkgName = dep_pkg(PkgConstraint), + Constraints1 = + case lists:keysearch(PkgName, 1, PkgsConstraints) of + false -> + []; + {value, {PkgName, Constraints0}} -> + Constraints0 + end, + [{PkgName, [{PkgConstraint, {SrcPkg, SrcVsn}} | Constraints1]} + | lists:keydelete(PkgName, 1, PkgsConstraints)]. + +%% @doc +%% Extend the currently active constraints correctly for the given constraints. +-spec extend_constraints(pkg_name(), vsn(), constraints(),constraints()) -> + [{pkg_name(), constraints()}]. +extend_constraints(SrcPkg, SrcVsn, ExistingConstraints0, NewConstraints) -> + lists:foldl(fun (Constraint, ExistingConstraints1) -> + add_constraint(SrcPkg, SrcVsn, ExistingConstraints1, Constraint) + end, + ExistingConstraints0, [{SrcPkg, SrcVsn} | NewConstraints]). + +-spec is_version_within_constraint(vsn(),constraint()) -> boolean(). +is_version_within_constraint(_Vsn, Pkg) when is_atom(Pkg) orelse is_binary(Pkg) -> + true; +is_version_within_constraint(Vsn, {_Pkg, NVsn}) -> + ec_semver:eql(Vsn, NVsn); +is_version_within_constraint(Vsn, {_Pkg, NVsn, '='}) -> + ec_semver:eql(Vsn, NVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, gte}) -> + ec_semver:gte(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, '>='}) -> + ec_semver:gte(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, lte}) -> + ec_semver:lte(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, '<='}) -> + ec_semver:lte(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, gt}) -> + ec_semver:gt(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, '>'}) -> + ec_semver:gt(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, lt}) -> + ec_semver:lt(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, '<'}) -> + ec_semver:lt(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, 'pes'}) -> + ec_semver:pes(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn, '~>'}) -> + ec_semver:pes(Vsn, LVsn); +is_version_within_constraint(Vsn, {_Pkg, LVsn1, LVsn2, between}) -> + ec_semver:between(LVsn1, LVsn2, Vsn); +is_version_within_constraint(_Vsn, _Pkg) -> + false. + +%% @doc +%% Get the currently active constraints that relate to the specified package +-spec get_constraints([{pkg_name(), constraints()}],pkg_name()) -> constraints(). +get_constraints(PkgsConstraints, PkgName) -> + case lists:keysearch(PkgName, 1, PkgsConstraints) of + false -> + []; + {value, {PkgName, Constraints}} -> + Constraints + end. + +%% @doc +%% Given a package name get the list of all versions available for that package. +-spec get_versions(dep_graph(),pkg_name()) -> [vsn()]. +get_versions(DepGraph, PkgName) -> + case gb_trees:lookup(PkgName, DepGraph) of + none -> + []; + {value, AllVsns} -> + [Vsn || {Vsn, _} <- AllVsns] + end. + +%% @doc +%% make sure a given name/vsn meets all current constraints +-spec valid_version(pkg_name(),vsn(),constraints()) -> boolean(). +valid_version(PkgName, Vsn, PkgConstraints) -> + lists:all(fun ({L, _ConstraintSrc}) -> + is_version_within_constraint(Vsn, L) + end, + get_constraints(PkgConstraints, PkgName)). + +%% @doc +%% Given a Package Name and a set of constraints get a list of package +%% versions that meet all constraints. +-spec constrained_package_versions(dep_graph(),pkg_name(),constraints()) -> + [vsn()]. +constrained_package_versions(State, PkgName, PkgConstraints) -> + Versions = get_versions(State, PkgName), + [Vsn || Vsn <- Versions, valid_version(PkgName, Vsn, PkgConstraints)]. + +%% Given a list of constraints filter said list such that only fail (for things +%% that do not match a package and pkg are returned. Since at the end only pkg() +%% we should have a pure list of packages. +-spec filter_package_constraints([constraint()]) -> fail | pkg(). +filter_package_constraints([]) -> + fail; +filter_package_constraints([PkgCon | PkgConstraints]) -> + case PkgCon of + {Pkg, _} when is_atom(Pkg); is_binary(Pkg) -> + filter_package_constraints(PkgConstraints); + {{_Pkg1, _Vsn} = PV, _} -> + PV; + {{_Pkg2, _Vsn, _R}, _} -> + filter_package_constraints(PkgConstraints); + {{_Pkg2, _Vsn1, _Vsn2, _R}, _} -> + filter_package_constraints(PkgConstraints) + end. + +%% @doc all_pkgs is one of the set of mutually recursive functions (all_pkgs and +%% pkgs) that serve to walk the solution space of dependency. +-spec all_pkgs(dep_graph(),[pkg()],[pkg_name()],[{pkg_name(), constraints()}], term()) -> + fail_detail() | [pkg()]. +all_pkgs(_State, Visited, [], Constraints, _PathInd) -> + PkgVsns = + [filter_package_constraints(PkgConstraints) + || {_, PkgConstraints} <- Constraints], + + %% PkgVsns should be a list of pkg() where all the constraints are correctly + %% met. If not we fail the solution. If so we return those pkg()s + case lists:all(fun({Pkg, Vsn}) -> + lists:all(fun({Constraint, _}) -> + is_version_within_constraint(Vsn, Constraint) + end, get_constraints(Constraints, Pkg)) + end, PkgVsns) of + true -> + PkgVsns; + false -> + {fail, [{Visited, Constraints}]} + end; +all_pkgs(State, Visited, [PkgName | PkgNames], Constraints, PathInd) + when is_atom(PkgName); is_binary(PkgName) -> + case lists:keymember(PkgName, 1, Visited) of + true -> + all_pkgs(State, Visited, PkgNames, Constraints, PathInd); + false -> + pkgs(State, Visited, PkgName, Constraints, PkgNames, PathInd) + end. + +%% @doc this is the key graph walker. Set of constraints it walks forward into +%% the solution space searching for a path that solves all dependencies. +-spec pkgs(dep_graph(),[pkg()], pkg_name(), [{pkg_name(), constraints()}], + [pkg_name()], term()) -> fail_detail() | [pkg()]. +pkgs(DepGraph, Visited, Pkg, Constraints, OtherPkgs, PathInd) -> + F = fun (Vsn) -> + Deps = get_dep_constraints(DepGraph, Pkg, Vsn), + UConstraints = extend_constraints(Pkg, Vsn, Constraints, Deps), + DepPkgs =[dep_pkg(Dep) || Dep <- Deps], + NewVisited = [{Pkg, Vsn} | Visited], + Res = all_pkgs(DepGraph, NewVisited, DepPkgs ++ OtherPkgs, UConstraints, PathInd), + Res + + end, + case constrained_package_versions(DepGraph, Pkg, Constraints) of + [] -> + {fail, [{Visited, Constraints}]}; + Res -> + lists_some(F, Res, PathInd) + end. + + +%% @doc This gathers the dependency constraints for a given package vsn from the +%% dependency graph. +-spec get_dep_constraints(dep_graph(), pkg_name(), vsn()) -> [constraint()]. +get_dep_constraints(DepGraph, PkgName, Vsn) -> + {Vsn, Constraints} = lists:keyfind(Vsn, 1, + gb_trees:get(PkgName, DepGraph)), + Constraints. + + +lists_some(F, Res, PathInd) -> + lists_some(F, Res, [], PathInd). + +-spec lists_some(version_checker(), [vsn()], term(), term()) -> vsn() | fail_detail(). +%% @doc lists_some is the root of the system the actual backtracing search that +%% makes the dep solver posible. It a takes a function that checks whether the +%% 'problem' has been solved and an fail indicator. As long as the evaluator +%% returns the fail indicator processing continues. If the evaluator returns +%% anything but the fail indicator that indicates success. +lists_some(_, [], FailPaths, _PathInd) -> + {fail, FailPaths}; +lists_some(F, [H | T], FailPaths, PathInd) -> + case F(H) of + {fail, FailPath} -> + case PathInd of + keep_paths -> + lists_some(F, T, [FailPath | FailPaths], PathInd); + _ -> + lists_some(F, T, [], PathInd) + end; + Res -> + Res + end. + +%% @doc given a graph and a set of top level goals return a graph that contains +%% only those top level packages and those packages that might be required by +%% those packages. +-spec trim_unreachable_packages(dep_graph(), [constraint()]) -> + dep_graph() | {error, term()}. +trim_unreachable_packages(State, Goals) -> + {_, NewState0} = new_graph(), + lists:foldl(fun(_Pkg, Error={error, _}) -> + Error; + (Pkg, NewState1) -> + PkgName = dep_pkg(Pkg), + find_reachable_packages(State, NewState1, PkgName) + end, NewState0, Goals). + +%% @doc given a list of versions and the constraints for that version rewrite +%% the new graph to reflect the requirements of those versions. +-spec rewrite_vsns(dep_graph(), dep_graph(), [{vsn(), [constraint()]}]) -> + dep_graph() | {error, term()}. +rewrite_vsns(ExistingGraph, NewGraph0, Info) -> + lists:foldl(fun(_, Error={error, _}) -> + Error; + ({_Vsn, Constraints}, NewGraph1) -> + lists:foldl(fun(_DepPkg, Error={error, _}) -> + Error; + (DepPkg, NewGraph2) -> + DepPkgName = dep_pkg(DepPkg), + find_reachable_packages(ExistingGraph, + NewGraph2, + DepPkgName) + end, NewGraph1, Constraints) + end, NewGraph0, Info). + +%% @doc Rewrite the existing dep graph removing anything that is not reachable +%% required by the goals or any of its potential dependencies. +-spec find_reachable_packages(dep_graph(), dep_graph(), pkg_name()) -> + dep_graph() | {error, term()}. +find_reachable_packages(_ExistingGraph, Error={error, _}, _PkgName) -> + Error; +find_reachable_packages(ExistingGraph, NewGraph0, PkgName) -> + case contains_package_version(NewGraph0, PkgName) of + true -> + NewGraph0; + false -> + case gb_trees:lookup(PkgName, ExistingGraph) of + {value, Info} -> + NewGraph1 = gb_trees:insert(PkgName, Info, NewGraph0), + rewrite_vsns(ExistingGraph, NewGraph1, Info); + none -> + {error, {unreachable_package, PkgName}} + end + end. + +%% @doc +%% Checks to see if a package name has been defined in the dependency graph +-spec contains_package_version(dep_graph(), pkg_name()) -> boolean(). +contains_package_version(Dom0, PkgName) -> + gb_trees:is_defined(PkgName, Dom0). |