Think User`s Manual

Think User`s Manual
Think User’s Manual
1
Introduction
The goal of this document is to give sufficient information to help users of the Think
platform to design and build component-based software. tool chain and languages a
straight and simple use of the Nuptse version of the Think framework.
Think is a native implementation of the Fractal component model[?]. Think (ThinkIs
Not a Kernel) can be used to develop OS kernels but Think is by no means specialized to this domain (the framework can be used to develop any C system or application).Thanks to the Fractal Component Model, Think adopts a clear separation between
architecture and components. As a consequence Think accelerates native software development by allowing intensive re-use of pre-defined software component and rapid
porting of execution infrastructure on new hardware targets. The current Think release
hosts a build chain and several language specifications.
Since its first design, Think has known several transformation throuh several version. The latest, called Nuptse focuses on simplcity and efficiency:
• it simplifies the burden of the developpers of think-based software by providinga
simplified languages, espacially for developpers of functional code. It enables
enhancement and simplification;
• it makes possible the generation of very efficient software by providing the possibility to better master the flexibility power and implementation (and so the
associated cost) of generated software.
For this reasons, this document focuses on the Nuptse version of Think.
A component library named Kortex is also hosted in the repository of the project1 .
Kortex includes many components, some of them being devoted to execution infrastructure and OS development (memory manager, interrupt handler, semaphores, runtime schedulers...). Functional code can be written in C extended with reserved names
representing architectural artefacts.
1 For historical reason, this library is hosted by the Think project in the svn repository but may be extracted
from it very soon.
1
This document is structured as follows. Section 1.1 gives some imputs on the general organisation of the sources of the projet, section 2 explains how to download and
install the build chain and section 4 shows how to compile a software through a helloworld example. Section 5 then details the key concepts required to design a Thinkbased software. The document finally describes the different languages of the platform: theInterface Description Language (IDL) in section 7, the Architecture Description Language (ADL) in section 8 and the Component Programing Language (CPL) in
section 9.
1.1
Organization
The Think project is hosted on the Objectweb server (http://think.objectweb.org). The
URL of the subversion repository is: svn+ssh://svn.forge.objectweb.org/svnroot/think.
The repository is structured ad follows:
• trunk : trunk of the v2 version of the framework.
• branches : branches of the v2 version of the framework.
• V3 : repository of the v3 version of the project (trunk and branches)
• Nuptse : repository of the ’nuptse’ version of the framework
• Codegen : source code of a package oriented for code generation and used in the
nuptse version
This document focusses on the nuptse version. The trunk and branches are structured as follows:
• fractal-c: includes the fractal idl files. All the control interfaces defined by the
fractal model (CI, CC, BC, LCC) are defined there.
• think: implementation of fractal interface in c
• thinkadl: contains the build chain which is the core of the Think project. This directory includes all the tooling that is needed for code generation and for driving
the gcc based compilation process of the generated files.
• kortex: contains an OS-oriented component library
• tools: this directory includes build tooling, scripts....
2
Installation
The build chain can be retrieved from the ObjectWeb site using svn.
2.1
Getting sources
Type ’svn co svn+ssh://[email protected]/svnroot/think/nuptse/trunk’.
Type ’cd trunk/thinkadl; ant dist’ to compile the build chain.
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2.2
Getting pre-compiled binaries
Type ’svn co svn+ssh://[email protected]/svnroot/think/nuptse/releases’.
Type ’cd releases; tar xvfz thinkadl release number.tgz’, where release number refers
to the release you want to use.
3
Requirements
Think Cross Tool chain can be deployed on many platforms. The required tool set on
the targeted platform can be checked on the list below:
• ant (preferably the last version... at least the 1.7.0 that can be downloaded on
http://ant.apache.org/
• java 5
• a C compiler
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Quick Start: helloworld example
The build chain takes as input a (Fractal Compliant) architectural description of the
tar-geted kernel written in ADL/IDL and a repository of component implementations
ADL (Architecture Description Language) and IDL (Interface description language)
are usedto describe the included components instances and the way they are interconnected in order to build up the kernel.
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5.1
Key concepts
Properties
6
How to compile an architecture
7
The Interface Description Language (IDL)
8
The Architecture Description Language (ADL)
8.1
Notations
8.2
Keywords
8.2.1
component
Usage Declares a component definition.
3
[ a b s t r a c t ] component <compDefName : DotName>
[ e x t e n d s <extCompDefName : DotName> ] {
...
}
Description Declares a component definition (i.e. a component type) named compDefName.
This definition may extends another definition named extCompDefName. Extending
a component definition is like inlining the whole content of the extended definition into
the extending one. Abstract component definition are component definition for which
the content is not totaly defined. Note that only abstract component declarations (see
?? and 8.2.6 for more details) can be of an abstract component definition.
Example The following code declares an abstract component definition named here.is.bar,
and another (concrete) component definition named here.is.foo as an extension
of here.is.bar.
a b s t r a c t component h e r e . i s . b a r {
provides itfTypeA as i t f a
c o n t a i n s subCompX = sumCompX
b i n d s t h i s . i t f a t o subCompX . i t f a
}
component h e r e . i s . f o o e x t e n d s h e r e . i s . b a r {
provides itfTypeB as i t f b
r e q u i r e s itfTypeC as i t f c
c o n t a i n s subCompY = subCompDefY
b i n d s t h i s . i t f b t o subCompY . i t f b
b i n d s subCompY . i t f c t o t h i s . i t f c
b i n d s subCompY . i t f a t o subCompX . i t f a
}
Above definition of here.is.foo is equivalent to:
component h e r e . i s . f o o {
provides itfTypeA as i t f a
provides itfTypeB as i t f b
r e q u i r e s itfTypeC as i t f c
c o n t a i n s subCompX = sumCompX
c o n t a i n s subCompY = subCompDefY
b i n d s t h i s . i t f a t o subCompX . i t f a
b i n d s t h i s . i t f b t o subCompY . i t f b
b i n d s subCompY . i t f c t o t h i s . i t f c
b i n d s subCompY . i t f a t o subCompX . i t f a
}
4
8.2.2
provides
Usage Declares a provided (a.k.a server) interface in a component definition.
p r o v i d e s <i t f T y p e : DotName> a s <i t f N a m e : Name>
[ i n <implemName> ]
Description Declares a provided (a.k.a server) interface named itfName of interface type itfType. **** TODO:single **** **** TODO:implem name **** ****
TODO:single **** **** TODO:in implem ****
Example The following code declares, in a component definition here.is.bar, a
provided interface named foo of interface type here.is.Foo.
i n t e r f a c e h e r e . i s . Foo {
void foo1 ( i n t a , i n t b ) ;
i n t foo2 ( char x ) ;
}
component h e r e . i s . b a r {
p r o v i d e s f o o a s h e r e . i s . Foo
}
8.2.3
requires
Usage Declares a provided (a.k.a server) interface in a component definition.
r e q u i r e s <i t f T y p e : DotName> a s <i t f N a m e : Name>
[ ( mandatory | o p t i o n a l ) ]
[ i n <implemName> ]
Description Declares a provided (a.k.a server) interface named itfName of interface type itfType. A client interface may be declared as optional or mandatory
(default is mandatory). Any mandatory interface of a component instance must be
bound to a server interface. The build chain will complain about unbound mandatory
interfaces and will consequently fail. **** TODO:in implem ****.
Example The following code declares, in a component definition here.is.bar, a
required interface named foo of interface type here.is.Foo.
i n t e r f a c e h e r e . i s . Foo {
void foo1 ( i n t a , i n t b ) ;
i n t foo2 ( char x ) ;
}
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component h e r e . i s . b a r {
r e q u i r e s f o o a s h e r e . i s . Foo
}
8.2.4
attribute
Usage Declares an attribute.
a t t r i b u t e <a t t T y p e : Type> <a t t N a m e : Name>
[ ”=” <v a l u e : E x p r e s s i o n > [ c o n s t ] ]
Description Declares an attribute named attName of type attType in a component definition. An initial value may be specified. This will be the value of the attribute
once the system initialized. If const is specified the attribute will be constant, that is,
will keep its initial value ant will not be modifiable at runtime. Usage in the functional
code may be replaced by the speficied value, so that trying to assign it in the functional
code will possibly lead to a compile-time error.
Example The following code declares three attributes in a component definition
here.is.bar. foo1 is an int and has no initial value, foo2 is of type short and will
be instanciated with 3 as initial value, foo3 is a constant char attribute which value is
10 and foo4 is a constant string attribute which value is ”hello world”.
component h e r e . i s . b a r {
a t t r i b u t e i n t foo1
a t t r i b u t e s h o r t foo2 = 3
a t t r i b u t e c h a r f o o 3 = 10 c o n s t
a t t r i b u t e s t r i n g foo4 = ” h e l l o world ” c o n s t
}
8.2.5
assigns
Usage Assigns a value to an attribute of a sub-component.
a s s i g n s <subCompName : Name>.< a t t N a m e : Name>
”=” <v a l u e : E x p r e s s i o n >
Description Assigns value value to attribure attName of sub-component subCompName.
subCompName must be the name of a sub-component declared in the component definition (see 8.2.6). If the attribute was already declared with a value, the latter is overwritten with the new value.
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Example The following code declares a component definition here.is.foo that
contains a sub-component subComp of type here.is.bar and assigns a new value
to its attribute att.
component h e r e . i s . b a r {
attribute int att = 1
}
component h e r e . i s . f o o {
c o n t a i n s subComp = h e r e . i s . b a r
a s s i g n s subComp . a t t = 2
}
8.2.6
contains
Usage Declares a sub-component in a component definition.
c o n t a i n s <subCompName : Name> ( : | = ) <compDef : DotName>
Description Declares a sub-component subCompName of component type compDef
in a component definition. The ”:” notation declares a abstract sub-component and
must be used If and only if compDef is an abstract component definition. In that case,
the enclosing defintion must also be abstract. Note however that an abstract component
definition must not necessarily contains abstract sub-components.
Example The following example declares an abstract component definition here.is.bar1
containing an abstract sub-component c of abstract component type here.is.foo1,
and a (concrete) component definition here.is.bar1 containing a (concrete) subcomponent c of (concrete) component type here.is.foo1.
a b s t r a c t component h e r e . i s . f o o 1 {
...
}
component h e r e . i s . f o o 2 {
...
}
a b s t r a c t component h e r e . i s . b a r 1 {
contains c : here . i s . foo
}
component h e r e . i s . b a r 2 {
contains c = here . i s . foo2
}
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8.2.7
singleton
Usage Forces a component definition to be instanciated only onced in a architecture..
singleton
Description Forces a component definition to be instanciated only onced in a architecture. Two component definitions that contain a declaration of a sub-component of
such a singleton definition will share the same instance at runtime.
Example The following code declares a singleton component definition here.is.foo,
a component definitions here.is.bar1 that contains a sub-component c1 of component type here.is.foo and a component definition here.is.bar2 that contains a sub-component c2 of component type here.is.foo, and a sub-component
c3 of component type here.is.bar1. In a instance x of the component type
here.is.bar2, x:c2 and x:c3:c1 are aliases and represent the same component
instance.
component h e r e . i s . f o o {
...
singleton
}
component h e r e . i s . b a r 1 {
c o n t a i n s c1 = h e r e . i s . f o o
}
component h e r e . i s . b a r 2 {
c o n t a i n s c2 = h e r e . i s . f o o
c o n t a i n s c3 = h e r e . i s . b a r 1
}
8.2.8
content
Usage Specifies a file that contains implementation code.
c o n t e n t <f i l e N a m e : DotName>
( [ f o r <impName : Name> ]
| [ raw ] )
Description Specifies that file which base name (i.e. without extension) is fileName
with dot replaced with file separator, contains implementation code for implementation
impName. The extension of the file name must be one of the following: ”.c”, ”.s”, ”.S”.
If multiple files exist with the same base name, the first file that fits the mentioned extensions will be used, in the mentioned order. If impName is omited, then the file will
be interpreted as containing code for the default implementation (see ??). Note that
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code of a particular implementation may be spread across several file.
If raw is specified, then the file is to contain code that does not directly implement
server interfaces but normal code instead and cannot make use of the model artefacts
(access attributes, call client interfaces, ...).
Files will be searched in the component reposiroty path list specified in the command
(see ??).
Example In the following example, if we suppose that rep1 and rep2 are in the
repository path list in that order, file rep1/a/b/f1.c contains code for the default implementation, files rep1/a/b/c/f2.c and rep2/a/b/f3.c contain code
for the implementation imp1, file rep2/a/b/c/f4.c contains code for the implementation imp2, and file rep1/a/b/d/f4.cis to be added as is. Note that
rep2/a/b/c/f2.c will be ignored.
component h e r e .
...
content
content
content
content
content
}
i s . foo {
a . b . f1
a . b . c . f 2 f o r imp1
a . b . f 3 f o r imp1
a . b . c . f 4 f o r imp2
a . b . d . f 5 raw
File structure:
rep1
+− a
+− b
+− f 1 . c
+− c
+− f 2 . c
rep2
+− a
+− b
+− f 3 . c
+− c
+− f 2 . c
+− d
+− f 5 . c
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8.2.9
cflags
8.3
Deprecated Keywords and constructions
9
The NuptC Component Programming Language
Nuptse provides a Component Programming Language (CPL) called NuptC to develop
functional code implementing the provided interfaces of component. Contrary to previous CPLs of Think, NuptC has been defined in order to:
• minimize the burden of the programers and clarify functional code by providing
clear keywords representing the component concepts;
• allows optimisations by providing keywords that do not reflect particular implementation of the meta-data.
The CPL extends the C language with architectural-oriented keywords.This is achieved
without extending the C syntax but instead providing keywords through reserved identifiers having well defined naming conventions. In order to allows arbitrary implementations and optimisations of the glue, thes identifiers do not reflect any particular
meta-data organization. These identifiers reify the architectural definitions found in the
corresponding ADL file, so that a programmer can declare a C function as implementing a method of a declared server interface, call a method of a declared client interface,
access a declared attribute, etc.
Functional code is parsed by the chain and is translated into an Abstract Syntax
Tree using the Codegen library2 (because nuptse does not extend the C grammar, files
can be parsed with the C parser provided by codegen and define a listener to handle the
specific keywords). This AST is then analyzed and transformed by the build chain and
the resulting C files are then produced before being compiled by a C compiler (along
with files containing the glue code). This section details how to develop functional
code using the Nuptse CPL.
9.1
Declaring a method of a server interface
The implementation of a method foo of a server interface bar can be declared as
follows3
i n t SRV bar
...
}
foo ( i n t a , char b ) {
2 Codegen
3 Note
is currently hosted by the project.
the double underscore ( ) between the interface name and the method name.
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9.2
Declaring private variables
Components can have a private variable, that will be instanciated once for each component instance. A private variable is very similiar to an atribute in its usage but differs
in the fact that it is not declared in the architecture description and so is not visible
nor modifiable from outside the component. This variable must be named PRIVATE
and can be of arbitrary type, thus, using the struct construction of the C language,
allowing the declaration of virtually any number of private data. For example :
i n t PRIVATE ;
or
struct {
int i ;
int j ;
} PRIVATE ;
This variable can be referenced in the code just like any other variable.
9.3
Calling a client interface
A client method foo of a client interface bar can be invoked as follows :
SRV itf meth ( . . . ) {
...
CLT bar foo (0 , 1 ) ;
...
}
Note that only server and private methods can call client methods.
9.4
Referencing an attribute
An attribute foo can be referenced as follows :
i n t i = ATT foo ;
ATT foo = 2 ;
ATT foo ++;
Note that constant attributes can not be modified, so the last two examples will no
be allowed in this case.
9.5
Declaring a private method
A private method is a C function that make use of architectural artifacts. A private
method foo can be declared as follows:
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PRV foo ( . . . ) {
}
Only server methods and private methods can access attributes or call client interfaces.
9.6
Advanced keywords for controller programming
NuptC also provide keywords for programming implementation of Fractal control interfaces. This keywords give a way to initialize implementation code with values concerning the architecture known at compile time and access and modify meta-data at
runtime. All these keywords start with META_.
9.6.1
Client Interfaces
META_NB_CLT_ITFS Compile-time value representing the number of client interfaces of the component.
META_CLTITF_TABLE Variable name that declares a table containing the name and
the id of each required interface. This table must be declared as an array of any
type, which size must be at least the number of client interfaces. The type if the
table is transformed into a array of struct with two fields:
• itfName the name if the interface
• itfId the id of the interface
The table is initialized with values known at compile time. For example if a
component requires two interfaces foo and bar, then the following declared
variable:
any META CLTITF TABLE [ META NB CLT ITFS ] ;
is transformed into the following code:
struct {
char ∗ itfName ;
any i t f I d ;
} META CLTITF TABLE [ META NB CLT ITFS ] = {
{ ” f o o ” , <f o o I d > } ,
{ ” b a r ” , <b a r I d > }
}
where fooId and barId are the identifiers of respectively the foo and bar
client interfaces.
META_CLT_ITF_SET Runtime function to set the server interface identifier corresponding to a given client interface identifier.
12
v o i d META CLT ITF SET ( any c l t I t f I d , any s r v I t f I d ) ;
META_CLT_ITF_GET Runtime function to get the server interface identifier corresponding to a given client interface identifier.
any META CLT ITF GET ( any c l t I t f I d ) ;
9.6.2
Server Interfaces
META_NB_SRV_ITFS Compile-time value representing the number of server interfaces of the component.
META_SRVITF_TABLE Variable name that declares a table containing the name and
the id of each provided interface. This table must be declared as an array of any
type, which size must be at least the number of server interfaces. The type if the
table is transformed into a array of struct with two fields:
• itfName the name if the interface
• itfId the id of the interface
The table is initialized with values known at compile time. For example if a
component provides two interfaces foo and bar, then the following declared
variable:
any META SRVITF TABLE [ META NB SRV ITFS ] ;
is transformed into the following code:
struct {
char ∗ itfName ;
any i t f I d ;
} META SRVITF TABLE [ META NB SRV ITFS ] = {
{ ” f o o ” , <f o o I d > } ,
{ ” b a r ” , <b a r I d > }
}
where fooId and barId are the identifiers of respectively the foo and bar
server interfaces.
9.6.3
Attributes
META_NB_ATTS Compile-time value representing the number of client interfaces of
the component.
META_ATT_SET Runtime function to set the value of an attribute given its identifier.
v o i d META ATT SET ( any a t t I d , any a t t V a l u e ) ;
META_ATT_GET Runtime function to get the value of an attribute given its identifier.
any META ATT GET ( any a t t I d ) ;
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9.6.4
Components
META_NB_SUB_COMPS Compile-time value representing the number of sub-components
of the component.
META_SUBCOMP_TABLE Variable name that declares a table containing the name
and the id of each sub component. This table must be declared as an array of any
type, which size must be at least the number of sub components. The type if the
table is transformed into a array of struct with two fields:
• compName the name of the sub component
• compId the id of the sub component
The table is initialized with values known at compile time. For example if a component contains two sub components foo and bar, then the following declared
variable:
any META\ SUBCOMP\ TABLE [META\ NB\ SUB\ COMPS ] ;
is transformed into the following code:
struct {
c h a r ∗ compName ;
any compId ;
} META\ SUBCOMP\ TABLE [META\ NB\ SUB\ COMPS ] = {
{ ” f o o ” , <f o o I d > } ,
{ ” b a r ” , <b a r I d > }
}
where fooId and barId are the identifiers of respectively the foo and bar
sub components.
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Extension Mechanism
The Architecture Description Language introduced in section 8 allows to define a component by extending another definition. Starting from a initial definition it is possible to
add new interfaces, new attributes or nes subcomponents. It is also possible to specify
new properties to existing interfaces, attributes, components, ... In the following, the
component definition staticComp extends the definition comp by making static the
declared interfaces. The extension mechanism give a way to extend multiple component definitions in a generic way using pattern matching. An extension specification is
a standard ADL file but where names can have ”jokers” that may match names found
in an architecture description. For example applying the following extension definition
make all bindings static of any component definition.
component ∗ ∗ . ∗ {
binds ∗.∗ to ∗.∗ [ s t a t i c ]
}
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The build chain takes a option ”ext-files” with ”:” separated For each component
specification found in the architecture given as input to the build chain, the extension
definition is matched to see
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