771 lines
35 KiB
Scheme
771 lines
35 KiB
Scheme
#| resolver.ss -- PLaneT client
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1. Introduction
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The PLaneT system is a method for automatically sharing code packages, both as libraries and
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as full applications, that gives every user of a PLaneT client the illusion of having a local copy
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of every code package on the server, but is parsimonious in its transmission. It consists of a
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centralized server that holds all packages and individual clients that hold some portion of the
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archive locally. Maintenance of that archive should be transparent, and is the complete
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responsibility of the PLaneT client.
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2. Client behavior
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The PLaneT client receives user requests (i.e., the "(require (planet ...))" forms) and loads the
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appropriate modules in response. In the course of handling these requests it may download new code
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packages from the PLaneT server.
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2.1 User interface
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The structure of user PLaneT invocations is listed below.
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PLANET-REQUEST ::= (planet FILE-NAME PKG-SPEC [PATH ...]?)
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FILE-NAME ::= string
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PKG-SPEC ::= string | (FILE-PATH ... PKG-NAME) | (FILE-PATH ... PKG-NAME VER-SPEC)
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VER-SPEC ::= Nat | (Nat MINOR)
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MINOR ::= Nat | (Nat Nat) | (= Nat) | (+ Nat) | (- Nat)
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FILE-PATH ::= string
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PKG-NAME ::= string
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OWNER-NAME ::= string
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PATH ::= string
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All strings must be legal filename strings.
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When encountered, a planet-request is interpreted as requiring the given file name from the given
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logical package, specified by the package spec and the collection specification, if given. If no
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VER-SPEC is provided, the most recent version is assumed. If no owner-name/path ... clause is
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provided, the default package is assumed.
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2. PLaneT protocol
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PLaneT clients support two protocols for communicating with the PLaneT server: the standard HTTP
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GET/response system (currently the default) and a specialized TCP-based protocol that may become
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more important if PLaneT becomes smarter about downloading packages behind the scenes.
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In the following sections we describe the specialized protocol only.
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2.1 Overview
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1. PLaneT client establishes TCP connection to PLaneT server.
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2. Client transmits a version specifier.
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3. Server either refuses that version and closes connection or accepts.
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4. Client transmits a sequence of requests terminated by a special end-of-request marker.
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Simultaneously, server transmits responses to those requests.
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5. Once the server has handled every request, it closes the connection.
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I am concerned about the overhead of opening and closing TCP connections for a large
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program with many requires, so I want to allow many requests and responses over the same
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connection. Unfortunately there's a wrinkle: the standard client, implemented the obvious
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way, would be unable to send more than one request at a time because it gets invoked purely
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as a response to a require form and must load an appropriate file before it returns. This
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means I can't batch up multiple requires, at least not with an obvious implementation.
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A possible solution would be to implement an install program that walks over the syntax
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tree of a program and gathers all requires, then communicates with the server and learns
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what additional packages would be necessary due to those requires, and then downloads all
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of them at once. We would have to implement both methods simultaneously, though, to allow
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for REPL-based PLaneT use and dynamic-require (unless we want it to be a runtime exception
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to use PLaneT from the REPL or via dynamic-require, something I'd rather not do), so I
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want a protocol that will allow both forms of access easily. This protocol does that, and
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doesn't require too much additional overhead in the case that the client only takes one
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package at a time.
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2.2 Communication Details
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After a TCP connection is established, the client transmits a VERSION-SPECIFIER:
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VERSION-SPECIFIER ::= "PLaneT/1.0\n"
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The server responds with a VERSION-RESPONSE:
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VERSION-RESPONSE ::=
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'ok "\n"
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| ('invalid string) "\n"
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where the string in the invalid case is descriptive text intended for display to the user
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that may indicate some specific message about the nature of the error.
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If the server sends 'invalid, the server closes the connection. Otherwise, the client may
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send any number of requests, followed by an end-of-request marker:
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REQUESTS ::= { REQUEST "\n"}* 'end "\n"
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REQUEST ::= (SEQ-NO 'get PKG-LANG PKG-NAME (Nat | #f) (Nat | #f) (Nat | #f) [OWNER-NAME PATH ...]?)
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PKG-LANG ::= String
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SEQ-NO ::= Nat
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The fields in a request are a uniquely identifying sequence number, the literal symbol 'get,
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the name of the package to receive, the required major version and the lowest and highest
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acceptable version (with #f meaning that there is no constraint for that field, and a #f in
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major-version field implying that both other fields must also be #f), and the package path.
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As the client is transmitting a REQUESTS sequence, the server begins responding to it with
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RESPONSE structures, each with a sequence number indicating to which request it is
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responding (except in the case of input too garbled to extract a sequence number):
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RESPONSE ::=
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| ('error 'malformed-input string) "\n"
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| (SEQ-NO 'error 'malformed-request string) "\n"
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| (SEQ-NO 'bad-language string) "\n"
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| (SEQ-NO 'get 'ok Nat Nat Nat) "\n" BYTE-DATA
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| (SEQ-NO 'get 'error ERROR-CODE string) "\n"
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ERROR-CODE ::= 'not-found
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If the server receives a malformed request, it may close connection after sending a
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malformed-request response without processing any other requests. Otherwise it must
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process all requests even in the event of an error. On a successful get, the three numbers
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the server returns are the matched package's major version, the matched package's minor version,
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and the number of bytes in the package.
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3 Client Download Policies
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Mzscheme invokes the PLaneT client once for each instance of a require-planet form in a program
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being run (i.e., the transitive closure of the "requires" relation starting from some specified
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root module; this closure is calculable statically). At each of these invocations, the client
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examines its internal cache to see if an appropriate module exists that matches the specification
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given by the user (for details see the next section). If one does, the client loads that module
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and returns. If none does, it initiates a transaction with the server using the PLaneT protocol
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described in the previous subsection and sends a single request consisting of the user's request.
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It installs the resulting .plt file and then loads the appropriate file.
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The client keeps a cache of downloaded packages locally. It does so in the
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$PLTCOLLECTS/planet/cache/ directory and subdirectories, in an intuitive manner: each item in
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the package's path in the PLaneT require line correspond to a subdirectory in the cache
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directory, starting with the owner name. (They should be unpacked relative to some user-specific
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rather than installation-specific place, possibly, but that's difficult to do so we won't do it
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yet).
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To check whether a package is installed when attempting to satisfy a requirement, the client
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checks its cache to see if an appropriate entry exists in its link-table for that require line.
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If one exists, it uses the named package directly. If none exists, it checks to see if there is
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an appropriate subdirectory.
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||#
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(module resolver mzscheme
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(require (lib "match.ss")
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(lib "file.ss")
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(lib "port.ss")
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(lib "list.ss")
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(lib "date.ss")
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(lib "url.ss" "net")
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(lib "head.ss" "net")
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(lib "struct.ss")
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"config.ss"
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"private/planet-shared.ss"
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"private/linkage.ss")
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(provide (rename resolver planet-module-name-resolver)
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resolve-planet-path
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pkg-spec->full-pkg-spec
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get-package-from-cache
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get-package-from-server
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download-package
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pkg->download-url
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pkg-promise->pkg
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install-pkg
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get-planet-module-path/pkg
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install?)
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(define install? (make-parameter #t)) ;; if #f, will not install packages and instead give an error
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(define resolver
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(case-lambda
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[(name) (void)]
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[(spec module-path stx load?)
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;; ensure these directories exist
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(make-directory* (PLANET-DIR))
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(make-directory* (CACHE-DIR))
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(establish-diamond-property-monitor)
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(planet-resolve spec module-path stx load?)]
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[(spec module-path stx) (resolver spec module-path stx #t)]))
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; ==========================================================================================
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; DIAMOND PROPERTY STUFF
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; make sure a module isn't loaded twice with two different versions
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; ==========================================================================================
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(define VER-CACHE-NAME #f)
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(define (establish-diamond-property-monitor)
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(unless VER-CACHE-NAME (set! VER-CACHE-NAME (gensym)))
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(unless (namespace-variable-value VER-CACHE-NAME #t (lambda () #f))
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(namespace-set-variable-value! VER-CACHE-NAME (make-hash-table 'equal))))
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(define (the-version-cache) (namespace-variable-value VER-CACHE-NAME))
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(define (pkg->diamond-key pkg) (cons (pkg-name pkg) (pkg-route pkg)))
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(define (pkg-matches-bounds? pkg bound-info)
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(match-let ([(maj lo hi) bound-info])
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(and (= maj (pkg-maj pkg))
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(or (not lo) (>= (pkg-min pkg) lo))
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(or (not hi) (<= (pkg-min pkg) hi)))))
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;; COMPAT ::= 'none | 'all | `(all-except ,VER-SPEC ...) | `(only ,VER-SPEC ...)
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;; build-compatibility-fn : COMPAT -> PKG -> bool
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(define (build-compatibility-fn compat-data)
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(define pre-fn
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(match compat-data
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[`none (lambda (_) #f)]
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[`all (lambda (_) #t)]
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[`(all-except ,vspec ...)
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(let ((bounders (map version->bounds vspec)))
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(if (andmap (lambda (x) x) bounders)
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(lambda (v)
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(not
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(ormap
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(lambda (bounder)
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(pkg-matches-bounds? v bounder))
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bounders)))
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#f))]
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[`(only ,vspec ...)
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(let ((bounders (map version->bounds vspec)))
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(if (andmap (lambda (x) x) bounders)
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(lambda (v)
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(andmap
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(lambda (bounder)
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(pkg-matches-bounds? v bounder))
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bounders)))
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#f)]
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[_ #f]))
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(or pre-fn (lambda (x) #f)))
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;; can-be-loaded-together? : pkg pkg -> boolean
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;; side constraint: pkg1 and pkg2 are versions of the same package
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;; assumption: pkg1 and pkg2 are versions of the same package
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;; determines if the two versions are side-by-side compatible
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(define (can-be-loaded-together? pkg1 pkg2)
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(cond
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[(pkg> pkg1 pkg2) (can-be-loaded-together? pkg2 pkg1)]
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[(pkg= pkg1 pkg2) #t]
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[(pkg< pkg1 pkg2)
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(let* ([info (pkg->info pkg2)]
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[compat? (build-compatibility-fn (info 'can-be-loaded-with (lambda () 'none)))])
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(compat? pkg1))]))
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;; stx->origin-string : stx option -> string
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;; returns a description [e.g. file name, line#] of the given syntax
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(define (stx->origin-string stx)
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(if stx
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(format "~a" (syntax-source stx))
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"[unknown]"))
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(define (add-pkg-to-diamond-registry! pkg stx)
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(let ((loaded-packages (hash-table-get (the-version-cache)
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(pkg->diamond-key pkg)
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(lambda () '()))))
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(begin
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(unless (list? loaded-packages)
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(error 'PLaneT "Inconsistent state: expected loaded-packages to be a list, received: ~s" loaded-packages))
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(let* ([all-violations '()]
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[_
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(for-each
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(lambda (already-loaded-pkg-record)
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(let* ([already-loaded-pkg (car already-loaded-pkg-record)]
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[stx (cadr already-loaded-pkg-record)]
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[stx-origin-string (stx->origin-string stx)])
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(unless (can-be-loaded-together? pkg already-loaded-pkg)
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(set!
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all-violations
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(cons
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(list
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stx
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(make-exn:fail
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(format
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"Package ~a loaded twice with multiple incompatible versions:
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~a attempted to load version ~a.~a while version ~a.~a was already loaded by ~a"
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(pkg-name pkg)
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(stx->origin-string stx)
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(pkg-maj pkg)
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(pkg-min pkg)
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(pkg-maj already-loaded-pkg)
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(pkg-min already-loaded-pkg)
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stx-origin-string)
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(current-continuation-marks)))
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all-violations)))))
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loaded-packages)])
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(unless (null? all-violations)
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(let ([worst (or (assq values all-violations) (car all-violations))])
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(raise (cadr worst)))))
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(hash-table-put! (the-version-cache)
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(pkg->diamond-key pkg)
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(cons (list pkg stx) loaded-packages)))))
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; ==========================================================================================
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; MAIN LOGIC
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; Handles the overall functioning of the resolver
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; ==========================================================================================
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; planet-resolve : PLANET-REQUEST symbol syntax[PLANET-REQUEST] -> symbol
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; resolves the given request. Returns a name corresponding to the module in the correct
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; environment
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(define (planet-resolve spec module-path stx load?)
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(let-values ([(path pkg) (get-planet-module-path/pkg spec module-path stx)])
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(when load? (add-pkg-to-diamond-registry! pkg stx))
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(do-require path (pkg-path pkg) module-path stx load?)))
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;; resolve-planet-path : planet-require-spec -> path
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;; retrieves the path to the given file in the planet package. downloads and installs
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;; the package if necessary
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(define (resolve-planet-path spec)
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(let-values ([(path pkg) (get-planet-module-path/pkg spec #f #f)])
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path))
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;; get-planet-module-path/pkg :PLANET-REQUEST symbol syntax[PLANET-REQUEST] -> path PKG
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;; returns the matching package and the file path to the specific request
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(define (get-planet-module-path/pkg spec module-path stx)
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(match (cdr spec)
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[(file-name pkg-spec path ...)
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(unless (string? file-name)
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(raise-syntax-error #f (format "File name: expected a string, received: ~s" file-name) stx))
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(unless (andmap string? path)
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;; special-case to catch a possibly common error:
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(if (ormap number? path)
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(raise-syntax-error #f (format "Module path must consist of strings only, received a number (maybe you intended to specify a package version number?): ~s" path) stx)
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(raise-syntax-error #f (format "Module path must consist of strings only, received: ~s" path) stx)))
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(match-let* ([pspec (pkg-spec->full-pkg-spec pkg-spec stx)]
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[result (get-package module-path pspec)])
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(cond [(string? result)
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(raise-syntax-error 'require result stx)]
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[(pkg? result)
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(values (apply build-path (pkg-path result)
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(append path (list file-name)))
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result)]))]
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[_ (raise-syntax-error 'require (format "Illegal PLaneT invocation: ~e" (cdr spec)) stx)]))
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;; PKG-GETTER ::= module-path pspec
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;; (pkg -> A)
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;; ((uninstalled-pkg -> void) (pkg -> void) ((string | #f) -> string | #f) -> A)
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;; -> A
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;;
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;; a pkg-getter is a function that tries to fetch a package; it is written in a quasi-cps style;
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;; the first argument is what it calls to succeed, and the second argument is what it calls when it
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;; fails. In the second case, it must provide two things: a function to take action if a match
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;; is found eventually, and a function that gets to mess with the error message if the entire message
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;; eventually fails.
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;; get-package : module-path FULL-PKG-SPEC -> (PKG | string)
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;; gets the package specified by pspec requested by the module in the given module path,
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;; or returns a descriptive error message string if that's not possible
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(define (get-package module-path pspec)
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(let loop ([getters (*package-search-chain*)]
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[pre-install-updaters '()]
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[post-install-updaters '()]
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[error-reporters '()])
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(cond
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[(null? getters)
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; we have failed to fetch the package, generate an appropriate error message and bail
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(let ([msg (foldl (λ (f str) (f str)) #f error-reporters)])
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(or msg
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(format "Could not find package matching ~s"
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(list (pkg-spec-name pspec)
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(pkg-spec-maj pspec)
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(list (pkg-spec-minor-lo pspec)
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(pkg-spec-minor-hi pspec))
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(pkg-spec-path pspec)))))]
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[else
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; try the next error reporter. recursive call is in the failure continuation
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((car getters)
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module-path
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pspec
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(λ (pkg)
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(when (uninstalled-pkg? pkg)
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(for-each (λ (u) (u pkg)) pre-install-updaters))
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(let ([installed-pkg (pkg-promise->pkg pkg)])
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(for-each (λ (u) (u installed-pkg)) post-install-updaters)
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installed-pkg))
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(λ (pre-updater post-updater error-reporter)
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(loop (cdr getters)
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(cons pre-updater pre-install-updaters)
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(cons post-updater post-install-updaters)
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(cons error-reporter error-reporters))))])))
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; pkg-spec->full-pkg-spec : PKG-SPEC syntax -> FULL-PKG-SPEC
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(define (pkg-spec->full-pkg-spec spec stx)
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(define (pkg name maj lo hi path) (make-pkg-spec name maj lo hi path stx (version)))
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(define (fail)
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(raise-syntax-error 'require (format "Invalid PLaneT package specifier: ~e" spec) stx))
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(match spec
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[((? string? path) ... ver-spec ...)
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(match (version->bounds ver-spec)
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[(maj min-lo min-hi)
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(pkg (last path) maj min-lo min-hi (drop-last path))]
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[#f (fail)])]
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[_ (fail)]))
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;; version->bounds : VER-SPEC -> (list (number | #f) number (number | #f)) | #f
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;; determines the bounds for a given version-specifier
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;; [technically this handles a slightly extended version of VER-SPEC where MAJ may
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;; be in a list by itself, because that's slightly more convenient for the above fn]
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(define (version->bounds spec-list)
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(match spec-list
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[() (list #f 0 #f)]
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[(? number? maj) (version->bounds (list maj))]
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[((? number? maj)) (list maj 0 #f)]
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[((? number? maj) min-spec)
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(let ((pkg (lambda (min max) (list maj min max))))
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(match min-spec
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[(? number? min) (pkg min #f)]
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[((? number? lo) (? number? hi)) (pkg lo hi)]
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[('= (? number? min)) (pkg min min)]
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[('+ (? number? min)) (pkg min #f)]
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[('- (? number? min)) (pkg 0 min)]))]
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[_ #f]))
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; ==========================================================================================
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; PHASE 2: CACHE SEARCH
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; If there's no linkage, there might still be an appropriate cached module
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; (either installed or uninstalled)
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; ==========================================================================================
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; get/installed-cache : pkg-getter
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(define (get/installed-cache module-spec pkg-spec success-k failure-k)
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(let ([p (lookup-package pkg-spec)])
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(if p (success-k p) (failure-k void void (λ (x) x)))))
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; get-package-from-cache : FULL-PKG-SPEC -> PKG | #f
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(define (get-package-from-cache pkg-spec)
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(lookup-package pkg-spec))
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;; get/uninstalled-cache-dummy : pkg-getter
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;; always fails, but records the package to the uninstalled package cache
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;; upon the success of some other getter later in the chain.
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(define (get/uninstalled-cache-dummy module-spec pkg-spec success-k failure-k)
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(failure-k save-to-uninstalled-pkg-cache! void (λ (x) x)))
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|
|
; get/uninstalled-cache : pkg-getter
|
|
; note: this does not yet work with minimum-required-version specifiers
|
|
; if you install a package and then use an older mzscheme
|
|
(define (get/uninstalled-cache module-spec pkg-spec success-k failure-k)
|
|
(let ([p (lookup-package pkg-spec (UNINSTALLED-PACKAGE-CACHE))])
|
|
(if (and p (file-exists? (build-path (pkg-path p) (pkg-spec-name pkg-spec))))
|
|
(success-k
|
|
; note: it's a little sloppy that lookup-pkg returns PKG structures, since
|
|
; it doesn't actually know whether or not the package is installed. hence
|
|
; I have to convert what appears to be an installed package into an
|
|
; uninstalled package
|
|
(make-uninstalled-pkg
|
|
(build-path (pkg-path p) (pkg-spec-name pkg-spec))
|
|
pkg-spec
|
|
(pkg-maj p)
|
|
(pkg-min p)))
|
|
(failure-k void void (λ (x) x)))))
|
|
|
|
;; save-to-uninstalled-pkg-cache! : uninstalled-pkg -> path[file]
|
|
;; copies the given uninstalled package into the uninstalled-package cache,
|
|
;; replacing any old file that might be there. Returns the path it copied
|
|
;; the file into.
|
|
(define (save-to-uninstalled-pkg-cache! uninst-p)
|
|
(let* ([pspec (uninstalled-pkg-spec uninst-p)]
|
|
[owner (car (pkg-spec-path pspec))]
|
|
[name (pkg-spec-name pspec)]
|
|
[maj (uninstalled-pkg-maj uninst-p)]
|
|
[min (uninstalled-pkg-min uninst-p)]
|
|
[dir (build-path (UNINSTALLED-PACKAGE-CACHE)
|
|
owner
|
|
name
|
|
(number->string maj)
|
|
(number->string min))]
|
|
[full-pkg-path (build-path dir name)])
|
|
(make-directory* dir)
|
|
(unless (equal? (normalize-path (uninstalled-pkg-path uninst-p)) (normalize-path full-pkg-path))
|
|
(when (file-exists? full-pkg-path) (delete-file full-pkg-path))
|
|
(copy-file (uninstalled-pkg-path uninst-p) full-pkg-path))
|
|
full-pkg-path))
|
|
|
|
; ==========================================================================================
|
|
; PHASE 3: SERVER RETRIEVAL
|
|
; Ask the PLaneT server for an appropriate package if we don't have one locally.
|
|
; ==========================================================================================
|
|
|
|
(define (get/server module-spec pkg-spec success-k failure-k)
|
|
(let ([p (get-package-from-server pkg-spec)])
|
|
(cond
|
|
[(pkg-promise? p) (success-k p)]
|
|
[(string? p)
|
|
; replace any existing error message with the server download error message
|
|
(failure-k void void (λ (_) p))])))
|
|
|
|
; get-package-from-server : FULL-PKG-SPEC -> PKG-PROMISE | #f | string[error message]
|
|
; downloads the given package file from the PLaneT server and installs it in the
|
|
; uninstalled-packages cache, then returns a promise for it
|
|
(define (get-package-from-server pkg)
|
|
(match (download-package pkg)
|
|
[(#t tmpfile-path maj min)
|
|
(let* ([upkg (make-uninstalled-pkg tmpfile-path pkg maj min)]
|
|
[cached-path (save-to-uninstalled-pkg-cache! upkg)]
|
|
[final (make-uninstalled-pkg cached-path pkg maj min)])
|
|
(unless (equal? (normalize-path tmpfile-path) (normalize-path cached-path))
|
|
(delete-file tmpfile-path)) ;; remove the tmp file, we're done with it
|
|
final)]
|
|
[(#f str) (string-append "PLaneT could not find the requested package: " str)]
|
|
[(? string? s) (string-append "PLaneT could not download the requested package: " s)]))
|
|
|
|
(define (download-package pkg)
|
|
((if (USE-HTTP-DOWNLOADS?)
|
|
download-package/http
|
|
download-package/planet)
|
|
pkg))
|
|
|
|
(define (current-time)
|
|
(let ((date (seconds->date (current-seconds))))
|
|
(parameterize ((date-display-format 'rfc2822))
|
|
(format "~a ~a:~a:~a"
|
|
(date->string date)
|
|
(date-hour date)
|
|
(date-minute date)
|
|
(date-second date)))))
|
|
|
|
|
|
; pkg-promise->pkg : pkg-promise -> pkg
|
|
; "forces" the given pkg-promise (i.e., installs the package if it isn't installed yet)
|
|
(define (pkg-promise->pkg p)
|
|
(cond
|
|
[(pkg? p) p]
|
|
[(uninstalled-pkg? p)
|
|
(install-pkg (uninstalled-pkg-spec p)
|
|
(uninstalled-pkg-path p)
|
|
(uninstalled-pkg-maj p)
|
|
(uninstalled-pkg-min p))]))
|
|
|
|
|
|
; install-pkg : FULL-PKG-SPEC path[file] Nat Nat -> PKG
|
|
; install the given pkg to the planet cache and return a PKG representing the installed file
|
|
(define (install-pkg pkg path maj min)
|
|
(unless (install?)
|
|
(raise (make-exn:fail
|
|
(format
|
|
"PLaneT error: cannot install package ~s since the install? parameter is set to #f"
|
|
(list (car (pkg-spec-path pkg)) (pkg-spec-name pkg) maj min))
|
|
(current-continuation-marks))))
|
|
|
|
(let* ((owner (car (pkg-spec-path pkg)))
|
|
(extra-path (cdr (pkg-spec-path pkg)))
|
|
(the-dir
|
|
(apply
|
|
build-path
|
|
(CACHE-DIR)
|
|
(append (pkg-spec-path pkg)
|
|
(list (pkg-spec-name pkg) (number->string maj) (number->string min))))))
|
|
(if (directory-exists? the-dir)
|
|
(raise (make-exn:fail
|
|
"Internal PLaneT error: trying to install already-installed package"
|
|
(current-continuation-marks)))
|
|
(begin
|
|
(with-logging
|
|
(LOG-FILE)
|
|
(lambda ()
|
|
(printf "\n============= Installing ~a on ~a =============\n"
|
|
(pkg-spec-name pkg)
|
|
(current-time))
|
|
;; oh man is this a bad hack!
|
|
(parameterize ((current-namespace (make-namespace)))
|
|
(let ([ipp (dynamic-require '(lib "plt-single-installer.ss" "setup") 'install-planet-package)])
|
|
(ipp path the-dir (list owner (pkg-spec-name pkg) extra-path maj min))))))
|
|
(make-pkg (pkg-spec-name pkg) (pkg-spec-path pkg) maj min the-dir)))))
|
|
|
|
; download-package : FULL-PKG-SPEC -> RESPONSE
|
|
; RESPONSE ::= (list #f string) | (list #t path[file] Nat Nat)
|
|
; downloads the given package and returns (list bool string): if bool is #t,
|
|
; the path is to a file that contains the package. If bool is #f, the package
|
|
; didn't exist and the string is the server's informative message.
|
|
; raises an exception if some protocol failure occurs in the download process
|
|
(define (download-package/planet pkg)
|
|
|
|
(define-values (ip op) (tcp-connect (PLANET-SERVER-NAME) (PLANET-SERVER-PORT)))
|
|
|
|
(define (close-ports)
|
|
(close-input-port ip)
|
|
(close-output-port op))
|
|
|
|
(define (request-pkg-list pkgs)
|
|
(for-each/n (lambda (pkg seqno)
|
|
(write-line (list* seqno 'get
|
|
(DEFAULT-PACKAGE-LANGUAGE)
|
|
(pkg-spec-name pkg)
|
|
(pkg-spec-maj pkg)
|
|
(pkg-spec-minor-lo pkg)
|
|
(pkg-spec-minor-hi pkg)
|
|
(pkg-spec-path pkg))
|
|
op))
|
|
pkgs)
|
|
(write-line 'end op)
|
|
(flush-output op))
|
|
|
|
(define (state:initialize)
|
|
(fprintf op "PLaneT/1.0\n")
|
|
(flush-output op)
|
|
(match (read ip)
|
|
['ok (state:send-pkg-request)]
|
|
[('invalid (? string? msg)) (state:abort (string-append "protocol version error: " msg))]
|
|
[bad-msg (state:abort (format "server protocol error (received invalid response): ~a" bad-msg))]))
|
|
|
|
(define (state:send-pkg-request)
|
|
(request-pkg-list (list pkg))
|
|
(state:receive-package))
|
|
|
|
(define (state:receive-package)
|
|
(match (read ip)
|
|
[(_ 'get 'ok (? nat? maj) (? nat? min) (? nat? bytes))
|
|
(let ((filename (make-temporary-file "planettmp~a.plt")))
|
|
(read-char ip) ; throw away newline that must be present
|
|
(read-n-chars-to-file bytes ip filename)
|
|
(list #t filename maj min))]
|
|
[(_ 'error 'malformed-request (? string? msg))
|
|
(state:abort (format "Internal error (malformed request): ~a" msg))]
|
|
[(_ 'get 'error 'not-found (? string? msg))
|
|
(state:failure (format "Server had no matching package: ~a" msg))]
|
|
[(_ 'get 'error (? symbol? code) (? string? msg))
|
|
(state:abort (format "Unknown error ~a receiving package: ~a" code msg))]
|
|
[bad-response (state:abort (format "Server returned malformed message: ~e" bad-response))]))
|
|
|
|
(define (state:abort msg)
|
|
(raise (make-exn:i/o:protocol msg (current-continuation-marks))))
|
|
(define (state:failure msg) (list #f msg))
|
|
|
|
(with-handlers ([void (lambda (e) (close-ports) (raise e))])
|
|
(begin0
|
|
(state:initialize)
|
|
(close-ports))))
|
|
|
|
;; ------------------------------------------------------------
|
|
;; HTTP VERSION OF THE PROTOCOL
|
|
|
|
;; pkg->servlet-args : FULL-PKG-SPEC -> environment[from (lib "url.ss" "net")]
|
|
;; gets the appropriate query arguments to request the given package from the
|
|
;; PLaneT HTTP download servlet
|
|
(define (pkg->servlet-args pkg)
|
|
(let ((get (lambda (access) (format "~s" (access pkg)))))
|
|
`((lang . ,(format "~s" (DEFAULT-PACKAGE-LANGUAGE)))
|
|
(name . ,(get pkg-spec-name))
|
|
(maj . ,(get pkg-spec-maj))
|
|
(min-lo . ,(get pkg-spec-minor-lo))
|
|
(min-hi . ,(get pkg-spec-minor-hi))
|
|
(path . ,(get pkg-spec-path)))))
|
|
|
|
;; get-http-response-code : header[from (lib "head.ss" "net")] -> string
|
|
;; gets the HTTP response code in the given header
|
|
(define (get-http-response-code header)
|
|
(let ((parsed (regexp-match #rx"^HTTP/[^ ]* ([^ ]*)" header)))
|
|
(and parsed (cadr parsed))))
|
|
|
|
;; pkg->download-url : FULL-PKG-SPEC -> url
|
|
;; gets the download url for the given package
|
|
(define (pkg->download-url pkg)
|
|
(copy-struct url (string->url (HTTP-DOWNLOAD-SERVLET-URL)) (url-query (pkg->servlet-args pkg))))
|
|
|
|
;; download-package/http : FULL-PKG-SPEC -> RESPONSE
|
|
;; a drop-in replacement for download-package that uses HTTP rather than the planet protocol.
|
|
;; The HTTP protocol does not allow any kind of complicated negotiation, but it appears that
|
|
;; many more users can make HTTP requests than requests from nonstandard protocols.
|
|
(define (download-package/http pkg)
|
|
(let/ec return
|
|
(let loop ([attempts 1])
|
|
(when (> attempts 5)
|
|
(return "Download failed too many times (possibly due to an unreliable network connection)"))
|
|
|
|
(with-handlers ([exn:fail:network? (λ (e) (return (exn-message e)))])
|
|
(let* ((target (pkg->download-url pkg))
|
|
(ip (get-impure-port target))
|
|
(head (purify-port ip))
|
|
(response-code/str (get-http-response-code head))
|
|
(response-code (string->number response-code/str)))
|
|
|
|
(define (abort msg)
|
|
(close-input-port ip)
|
|
(return msg))
|
|
|
|
(case response-code
|
|
[(#f) (abort (format "Server returned invalid HTTP response code ~s" response-code/str))]
|
|
[(200)
|
|
(let ((maj/str (extract-field "Package-Major-Version" head))
|
|
(min/str (extract-field "Package-Minor-Version" head))
|
|
(content-length/str (extract-field "Content-Length" head)))
|
|
(unless (and maj/str min/str content-length/str
|
|
(nat? (string->number maj/str))
|
|
(nat? (string->number min/str))
|
|
(nat? (string->number content-length/str)))
|
|
(abort "Server did not include valid major and minor version information"))
|
|
(let* ((filename (make-temporary-file "planettmp~a.plt"))
|
|
(maj (string->number maj/str))
|
|
(min (string->number min/str))
|
|
(content-length (string->number content-length/str)))
|
|
(let ([op (open-output-file filename 'truncate/replace)])
|
|
(copy-port ip op)
|
|
(close-input-port ip)
|
|
(close-output-port op)
|
|
(if (= (file-size filename) content-length)
|
|
(list #t filename maj min)
|
|
(loop (add1 attempts))))))]
|
|
[(404)
|
|
(begin0
|
|
(list #f (format "Server had no matching package: ~a" (read-line ip)))
|
|
(close-input-port ip))]
|
|
[(400)
|
|
(abort (format "Internal error (malformed request): ~a" (read-line ip)))]
|
|
[(500)
|
|
(abort (format "Server internal error: ~a"
|
|
(apply string-append
|
|
(let loop ()
|
|
(let ((line (read-line ip)))
|
|
(cond
|
|
[(eof-object? line) '()]
|
|
[else (list* line "\n" (loop))]))))))]
|
|
[else
|
|
(abort (format "Internal error (unknown HTTP response code ~a)" response-code))]))))))
|
|
|
|
; ==========================================================================================
|
|
; MODULE MANAGEMENT
|
|
; Handles interaction with the module system
|
|
; ==========================================================================================
|
|
|
|
; do-require : path path symbol syntax -> symbol
|
|
; requires the given filename, which must be a module, in the given path.
|
|
(define (do-require file-path package-path module-path stx load?)
|
|
(parameterize ((current-load-relative-directory package-path))
|
|
((current-module-name-resolver)
|
|
file-path
|
|
module-path
|
|
stx
|
|
load?)))
|
|
|
|
(define *package-search-chain*
|
|
(make-parameter
|
|
(list
|
|
get/linkage
|
|
get/installed-cache
|
|
get/uninstalled-cache-dummy
|
|
get/server
|
|
get/uninstalled-cache)))
|
|
|
|
|
|
; ============================================================
|
|
; UTILITY
|
|
; A few small utility functions
|
|
|
|
(define (last l) (car (last-pair l)))
|
|
|
|
;; make-directory*/paths : path -> (listof path)
|
|
;; like make-directory*, but returns what directories it actually created
|
|
(define (make-directory*/paths dir)
|
|
(let ((dir (if (string? dir) (string->path dir) dir)))
|
|
(let-values ([(base name dir?) (split-path dir)])
|
|
(cond
|
|
[(directory-exists? dir)
|
|
'()]
|
|
[(directory-exists? base)
|
|
(make-directory dir)
|
|
(list dir)]
|
|
[else
|
|
(let ((dirs (make-directory*/paths base)))
|
|
(make-directory dir)
|
|
(cons dir dirs))])))))
|