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-
-<!ENTITY modest-ModestConf SYSTEM "xml/modest-conf.xml">
-
-<!ENTITY index-Object-Tree SYSTEM "xml/tree_index.sgml">
-<!ENTITY index-Object-Index SYSTEM "xml/object_index.sgml">
-]>
-
-<book id="index">
+ "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<book id="index" xmlns:xi="http://www.w3.org/2003/XInclude">
<bookinfo>
- <title>modest reference manual</title>
+ <title>modest technical documentation</title>
+ <copyright>
+ <year>2006</year>
+ <holder>Nokia Corporation</holder>
+ </copyright>
</bookinfo>
<preface>
<title>Introduction</title>
- <para>modest is a lightweight e-mail program, built on top of
- tinymail and libcamel</para>
- </preface>
-
- <reference>
- <title>Object Index</title>
- &index-Object-Index;
- &index-Object-Tree;
- </reference>
-
- <reference>
- <title>API Reference</title>
+ <para><application>modest</application> is a mail user agent
+ (<abbrev>MUA</abbrev>) targetting small devices, in particular Nokia's
+ <productname>Nokia 770 Internet Tablet</productname>. This document
+ describes the design and implementation of this software.
+ </para>
+
+ <para><application>modest</application> lives at the top of a extensive
+ stack of software. It is built on top
+ of <application>tinymail</application>, and uses its libcamel
+ backend. It strives to the be a simple yet powerful program, geared
+ towards small devices, for example (but not limited
+ to) <productname>Nokia's 770 internet tablet</productname>. An important
+ goal is to minimize memory usage while still being able to handle
+ significant amounts of email quickly; much of that is achieved simply by
+ using <application>tinymail</application>, which uses a number of clever
+ tricks for that, such as the proxy design pattern for listing email
+ headers, and not needing memory for headers which are not currently
+ visible.
+ </para>
+
+ <para>
+ <application>modest</application>, in turn, also tries to be efficient,
+ fast and scalable. That means that the <abbrev>MUA</abbrev> should
+ support multiple user-interfaces, perhaps making it even possible to
+ switch between them during runtime.
+ </para>
+
+ <para>To summarize the goals for <application>modest</application>:
+ <itemizedlist>
+ <listitem>target devices with limited amounts of memory ('limited' in 2006
+ terms means less than 64Mb, and of which only part can be used for
+ e-mail);</listitem>
+ <listitem>target Linux/Unix-like environments with GLib/GTK+-based
+ support;</listitem>
+ <listitem>support multiple user-interface (UIs) with as much code
+ sharing as possible between the different UIs.</listitem>
+ </itemizedlist></para>
+
+ <para>Like <application>tinymail</application>
+ and <application>libcamel</application>, <application>modest</application>
+ is programmed in C, using the <package>GObject</package>-system for
+ object-oriented (OO) features. For now, it specifically targets \gtk based
+ UIs (and derivatives like 'Hildon').</para>
- <chapter id="modest-core">
- <title>modest general</title>
- &modest-ModestConf;
- </chapter>
+ </preface>
- </reference>
+ <part>
+ <title>Architecture</title>
+ <partintro>
+ <para><application>modest</application> tries to be quite flexible in its
+ design. However, it's always important not to make things too
+ generic. Both for reasons of time limitations and keeping the software
+ understandable and 'modest', it's important to limit the scope.
+ </para>
+
+ <para>
+ For <application>modest</application>, the following:
+ <itemizedlist>
+ <listitem><application>modest</application> is a e-mail program
+ using the <package>tinymail</package> and <package>camel</package>
+ libraries;</listitem>
+ <listitem><application>modest</application> targets gtk and
+ gconf-based user-interfaces, including the Hildon
+ environment;</listitem>
+ <listitem><application>modest</application> main use-case is in
+ small, mobile device such as the <productname>Nokia 770 Internet
+ Tablet</productname>;</listitem>
+ <listitem>However, effort is made also to
+ make <application>modest</application> usable as a general-purpose
+ e-mail client on normal desktop computer.</listitem>
+ </itemizedlist>
+ </para>
+ </partintro>
+ </part>
+
+ <part>
+ <title>Design</title>
+ <partintro>
+ <para>In this part, we'll discuss the design of various parts of
+ <application>modest</application>. We'll not go into the details of
+ various APIs in this chapter. Please consult the documentation generated
+ from the source code (<systemitem>gtk-doc</systemitem>) for that.
+ </para>
+ </partintro>
+
+ <chapter>
+ <title>Configuration</title>
+ <para>Configuration is the part of <application>modest</application>
+ that deals with storing all settings. While the design allows for
+ alternative implementations, currently
+ only <systemitem>GConf</systemitem> is supported as a backend.
+ </para>
+
+ <para>
+ All dealing with configuration is done with
+ the <classname>ModestConf</classname>-class. It is declared
+ in <filename> modest-conf.h</filename>, and
+ the <systemitem>GConf</systemitem>-based implementation in
+ <filename>modest-conf.c</filename>. As said, there could be
+ different implementations --
+ nothing <systemitem>GConf</systemitem>-specific is visible in the
+ <classname>ModestConf</classname>-<abbrev>API</abbrev>.
+ </para>
+ </chapter>
+
+ <chapter>
+ <title>Account Management</title>
+ <para>
+ Account Management is the part of <application>modest</application>
+ that deals with the setting related to sending and receiving of
+ e-mail. We will follow the libcamel-convention of using the
+ term <emphasis>store</emphasis> for an e-mail storage/retrieval
+ server, and a <emphasis>transport</emphasis> for a server that
+ transports mail to its destination.
+ </para>
+
+ <para>
+ In practice, the following types are available:
+ <itemizedlist>
+ <listitem><emphasis>stores</emphasis>: <abbrev>POP</abbrev>
+ and <abbrev>IMAP</abbrev>; </listitem>
+ <listitem> <emphasis>transports</emphasis>: <systemitem>sendmail</systemitem>
+ and <abbrev>SMTP</abbrev>.</listitem>
+ </itemizedlist>
+ </para>
+
+ <sect1>
+ <title>Definitions</title>
+ <itemizedlist>
+ <listitem>An <emphasis>account</emphasis> is a named entity
+ consisting of a <emphasis>store</emphasis> and
+ a <emphasis>transport</emphasis>. Note: For our mobile use-cases,
+ the <emphasis>transport</emphasis> cannot be a static entity, but
+ may depend on the network connection. That is however not part of
+ Account Management, so not discussed here</listitem>
+ <listitem>A <emphasis>server account</emphasis> is account
+ describing the connection with a specific server. Server accounts
+ come in two type:
+ <itemizedlist>
+ <listitem>A <emphasis>transport</emphasis> describes the connection information
+ (servername, username, password etc.) for a transport
+ server;</listitem>
+ <listitem>A <emphasis>store</emphasis> describes the connection information for
+ a store server;</listitem>
+ </itemizedlist>
+ </listitem>
+ </itemizedlist>
+ </sect1>
+
+ <sect1>
+ <title>Code</title>
+ <para>The functions to deal with account and server accounts are
+ located in <classname>ModestAccountMgr</classname>, ie. in
+ <filename>modest-account-mgr.[ch]</filename>. There function to add
+ specific values for both, to list the available ones, etc. Please
+ refer to the source code documentation for details.
+ </para>
+ </sect1>
+
+ <sect1>
+ <title>Location in configuration database</title>
+ <para>
+ <emphasis>Accounts</emphasis> can be found
+ in <systemitem>/apps/modest/accounts</systemitem>,
+ while <emphasis>server accounts</emphasis> can be found
+ in <systemitem>/app/modest/server_accounts</systemitem>.
+ </para>
+
+ <para>
+ The following image show an
+ account <systemitem>accountstest</systemitem> with server accounts
+ <systemitem>mystore</systemitem>
+ and <systemitem>mytransport</systemitem>.
+ <imagedata fileref="modest-account-mgr.png"/>
+ </para>
- <index>
- <title>Index</title>
- </index>
+ <para>
+ For each of the stores, there are number of parameters specified:
+ <itemizedlist>
+ <listitem><emphasis>hostname</emphasis> - the place where the server resides;</listitem>
+ <listitem><emphasis>username</emphasis> - the username;</listitem>
+ <listitem><emphasis>password</emphasis> - the password;</listitem>
+ <listitem><emphasis>proto</emphasis> - the protocal for communication with this server - for
+ now these are the following valid values (literal strings):
+ <itemizedlist>
+ <listitem><emphasis>sendmail</emphasis>;</listitem>
+ <listitem><emphasis>smtp</emphasis>;</listitem>
+ <listitem><emphasis>pop</emphasis></listitem>
+ <listitem><emphasis>imap</emphasis>.</listitem>
+ </itemizedlist>
+ </listitem>
+ </itemizedlist>
+ </para>
+
+ <para>In <filename>modest-proto.[ch]</filename> there are various
+ functions to check whether something is a valid protocol, and
+ whether it is a transport of a store.
+ </para>
+
+ <para>Note that server accounts and accounts are relatively independent. While
+ accounts refer to two server accounts, these server accounts can be
+ used by other accounts as well.
+ </para>
+
+ <para>The reason two keep accounts and server accounts separately, is a bit of
+ flexibility. In mobile use-cases, quite often it's desirable to use a
+ network-specific smtp-server. The chosen structure makes it easy to iterate
+ over all smtp-servers and find the right one.
+ </para>
+ </sect1>
+
+ <sect1>
+ <title>Account Management and Tinymail</title>
+ <para>
+ Tinymail needs the information about all configured accounts - and the
+ mechanism that it uses for that
+ is <interface>TnyAccountStoreIface</interface>. We don't want to use
+ the tinymail-provided <classname>TnyAccountStore</classname>, but
+ provide our own implementation
+ instead: <classname>ModestTnyAccountStore</classname>. This class
+ implements the <interface>TnyAccountStoreIface</interface>-interace in
+ terms of the aforementioned <classname>ModestAccountMgr</classname>.
+ </para>
+
+ <para>
+ One unexpected function
+ that <classname>ModestTnyAccountStore</classname> needs to implement
+ is <symbol>tny account_store get_session</symbol> (to get the
+ Camel-session). This function must be provided as a public function,
+ with that exact name.
+ </para>
+ </sect1>
+ </chapter>
+
+ <chapter>
+ <title>Finding the right transport</title>
+ <para>
+ One of the interesting topics in designing a mobile e-mail client is
+ to deal with transports (in
+ particular, <acronym>SMTP</acronym>). The reason for that is that
+ the majority of <acronym>SMTP</acronym>-servers only allow e-mail
+ from the same network. That means that for example <systemitem>
+ smtp.some-isp.com</systemitem> will only accept mail from
+ (<command>MAIL FROM:</command>) <systemitem>
+ user@some-isp.com</systemitem>, and refuse mail
+ from <systemitem>user@some-other-isp.com</systemitem>, unless the
+ recipient (<command>RCPT TO:</command>) is on the same network.
+ </para>
+ </chapter>
+ </part>
+ <chapter>
+ <title>Coding guidelines</title>
+ <para>
+ When hacking on modest, please honour these time-tested coding guidelines.
+ First, please follow the <emphasis>Linux CodingStyle guidelines</emphasis>
+ (<filename>/usr/src/linux/Documentation/CodingStyle</filename>).
+ </para>
+
+ <para>
+ Here are only some additional notes.
+ </para>
+
+ <para>
+ Your editor may help you with this, for example for <application>emacs</application>:
+ <programlisting>
+ (c-set-style "K&R")
+ (setq tab-width 8)
+ (setq indent-tabs-mode t)
+ (setq c-basic-offset 8)
+ </programlisting>
+
+ Or the equivalent in your favourite editor.
+ </para>
+
+ <para>
+ Lines must not exceed 100 characters.
+ </para>
+
+ <para>
+ Functions should do one thing, and do it well. In general, functions
+ should not be much longer than 20-30 lines (except for, say, handling
+ many different cases in a 'switch'-statement). Files should not get to
+ big either; if there are more than, say, 800 lines, it's a sign that
+ some refactoring should take place.
+ </para>
+
+ <para>
+ Code should compile cleanly
+ with <command>gcc</command>'s <symbol>-Wall</symbol> compile option. Of
+ course this might not always be possible due to problems in dependent
+ libraries and/or compiler version. Therefore, do not
+ include <symbol>-Werror</symbol> in the standard compile options.
+ </para>
+
+ <para>Global functions (the ones in <filename>.h</filename>-files) must
+ be commented using <systemitem>gtk-doc</systemitem>. This way, we
+ generate nice documentation. After installing
+ (under <filename>/usr/local</filename>), we can browse the results
+ with <application>DevHelp</application>. Just
+ add <systemitem>/usr/local/share/gtk-doc/html</systemitem> to the
+ <systemitem>DEVHELP_SEARCH_PATH</systemitem>-environment variable.
+ </para>
+ <para>
+ Furthermore, please follow 'conventional wisdom' for programming with
+ GLib/GTK+/GObject. Some things to remember:
+ <itemizedlist>
+ <listitem> <function>g_new</function>, <function>g_malloc</function> and
+ friends <emphasis>never</emphasis> return <function>NULL</function>. They terminate
+ the application if it happens (normally). No need to check
+ for <function>NULL</function> returns;</listitem>
+ <listitem> <function>g_return_if_fail</function> and friends may be
+ 'turned off', ie. they are to be used for error checking,
+ but <emphasis>not</emphasis> for your programming logic
+ </listitem>
+ </itemizedlist>
+ </para>
+ </chapter>
+
+ <chapter>
+ <title>Object Index</title>
+ </chapter>
+
+ <chapter>
+ <title>API Reference</title>
+ <xi:include href="xml/modest-ui.xml"/>
+ <xi:include href="xml/modest-tny-header-tree-view.xml"/>
+ <xi:include href="xml/modest-tny-msg-view.xml"/>
+ <xi:include href="xml/modest-account-mgr.xml"/>
+ <xi:include href="xml/modest-conf.xml"/>
+ <xi:include href="xml/modest-window-mgr.xml"/>
+ <xi:include href="xml/modest-tny-folder-tree-view.xml"/>
+ <xi:include href="xml/modest-tny-account-store.xml"/>
+ <xi:include href="xml/modest-tny-transport-actions.xml"/>
+ <xi:include href="xml/modest-main-window.xml"/>
+ <xi:include href="xml/modest-editor-window.xml"/>
+ <xi:include href="xml/modest-viewer-window.xml"/>
+ <xi:include href="xml/modest-proto.xml"/>
+ <xi:include href="xml/modest-account-keys.xml"/>
+ <xi:include href="xml/modest-conf-keys.xml"/>
+ </chapter>
</book>
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projects / modest / blobdiff