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In Symbian OS versions earlier than 9.4, POP3 and IMAP email MTMs used the rich text format for storing email messages. These MTMs create the entire email message received from the email servers, and stores and commits into the mail store synchronously.
From Symbian OS v9.4 onwards, POP3 and IMAP email MTMs can use the plain text format for storing email messages. The entire email message is not created in the RAM. Only chunks of the message are stored in the RAM at a time, as writing or reading is done asynchronously. This decreases RAM usage and increases the performance of downloading and storing email messages.
The CMsvStore
class is modified with the following
APIs to enable chunk method:
A chunk is a substantial amount of an encapsulated email message that is processed in plain text format. The following table provides the default chunk size value that you can have for POP, IMAP, and SMTP.
Protocol | Default chunk size |
---|---|
POP |
2000 bytes |
IMAP |
20480 bytes
You can modify this value using the
|
SMTP |
2000 bytes |
The chunk method enables you to limit the need for outbound buffering of an email message in RAM on the client side. It modifies (breaks) the body of a message in order to transfer it as a series of chunks. Each chunk contains a size indicator, followed by a flag that contains entity-header fields, which can be used by the recipient to verify if the email message received is complete or partial.
The method of processing email messages in chunks (plain text format) is provided in addition to processing email messages in rich text format. Licensees can choose the type of configuration to store and/or restore email messages. If this mechanism is not configured, email messages are stored and/or restored in the rich text format.
Set the store_plain_body_text
field to any of the
following values at the client side. This value is used to configure the IMAP
and POP3 MTMs to decide the type of storage to be used for storing email
messages.
Locate the IMCM.rss
file at the
messaging\email\clientmtms\group
location.
Set the value of the store_plain_body_text
field to
any of the following values:
Value | Description |
---|---|
|
To store the body text of an email message in chunks when messages are downloaded through IMAP and POP3. This is the default value. |
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To store the entire body text of an email message in the RAM when messages are downloaded through IMAP and POP3. |