%% -*- 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 = rlx_depsolver:new_graph(),
%%% Graph1 = rlx_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 rlx_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.
%%%
%%% rlx_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
%%%
%%% rlx_depsolver:solve(Graph1, [{app3, "0.3", '>='}]).
%%%
%%% Of course, you can specify any number of goals at the top level.
%%% @end
%%%-------------------------------------------------------------------
-module(rlx_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 rlx_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.
%%
%% ``` rlx_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.
%% ```rlx_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.
%% ```rlx_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.
%%
%% ```rlx_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.
%% ``` rlx_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, rlx_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) ->
rlx_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) ->
rlx_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) ->
rlx_depsolver_culprit:format_culprits(Culprits).
%% @doc A formatted version tuple
-spec format_version(vsn()) -> iolist().
format_version(Version) ->
rlx_depsolver_culprit:format_version(Version).
%% @doc A formatted constraint tuple
-spec format_constraint(constraint()) -> iolist().
format_constraint(Constraint) ->
rlx_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).
