[PATCH 07/23] support splitting mail from database location.

[David Bremner <david@tethera.net>]

Introduce a new configuration value for the mail root, and use it in
preference to the database.path (which previously implied the mail was
also in this location.

Multiple changes to the CLI and third party clients will be needed to
work in this split configuration.
---
 doc/man1/notmuch-config.rst | 14 +++++++--
 lib/config.cc               | 11 +++++--
 lib/database.cc             |  2 +-
 lib/message-file.c          |  2 +-
 lib/message.cc              |  2 +-
 lib/notmuch.h               |  1 +
 test/T055-path-config.sh    | 60 +++++++++++++++++++++++++++++++++++++
 test/T590-libconfig.sh      |  1 +
 8 files changed, 84 insertions(+), 9 deletions(-)
 create mode 100755 test/T055-path-config.sh

diff --git a/doc/man1/notmuch-config.rst b/doc/man1/notmuch-config.rst
index bc597957..ec8c10d5 100644
--- a/doc/man1/notmuch-config.rst
+++ b/doc/man1/notmuch-config.rst
@@ -43,12 +43,20 @@ configuration file and corresponding database.
 The available configuration items are described below.
 
 **database.path**
+    Notmuch will store its database within a
+    sub-directory of the path configured here named ``.notmuch``.
+
+    Default: ``$MAILDIR`` variable if set, otherwise ``$HOME/mail``.
+
+**database.mail_root**
     The top-level directory where your mail currently exists and to
     where mail will be delivered in the future. Files should be
-    individual email messages. Notmuch will store its database within
-    a sub-directory of the path configured here named ``.notmuch``.
+    individual email messages.
 
-    Default: ``$MAILDIR`` variable if set, otherwise ``$HOME/mail``.
+    History: this configuration value was introduced in notmuch 0.32.
+
+    Default: For compatibility with older configurations, the value of
+    database.path is used if database.mail\_root is unset..
 
 **database.hook_dir**
 
diff --git a/lib/config.cc b/lib/config.cc
index 948751bc..bfa6b4ae 100644
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -390,6 +390,8 @@ _notmuch_config_key_to_string (notmuch_config_key_t key) {
     switch (key) {
     case NOTMUCH_CONFIG_DATABASE_PATH:
 	return "database.path";
+    case NOTMUCH_CONFIG_MAIL_ROOT:
+	return "database.mail_root";
     case NOTMUCH_CONFIG_HOOK_DIR:
 	return "database.hook_dir";
     case NOTMUCH_CONFIG_EXCLUDE_TAGS:
@@ -412,18 +414,21 @@ _notmuch_config_key_to_string (notmuch_config_key_t key) {
 }
 
 static const char *
-_notmuch_config_default (void *ctx, notmuch_config_key_t key) {
+_notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key) {
     char *path;
 
     switch (key) {
     case NOTMUCH_CONFIG_DATABASE_PATH:
 	path = getenv ("MAILDIR");
 	if (path)
-	    path = talloc_strdup (ctx, path);
+	    path = talloc_strdup (notmuch, path);
 	else
-	    path = talloc_asprintf (ctx, "%s/mail",
+	    path = talloc_asprintf (notmuch, "%s/mail",
 				    getenv ("HOME"));
 	return path;
+    case NOTMUCH_CONFIG_MAIL_ROOT:
+	/* by default, mail root is the same as database path */
+	return notmuch_database_get_path (notmuch);
     case NOTMUCH_CONFIG_EXCLUDE_TAGS:
 	return "";
     case NOTMUCH_CONFIG_NEW_TAGS:
diff --git a/lib/database.cc b/lib/database.cc
index b231a619..1fc3ce9c 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1345,7 +1345,7 @@ _notmuch_database_relative_path (notmuch_database_t *notmuch,
     const char *db_path, *relative;
     unsigned int db_path_len;
 
-    db_path = notmuch_database_get_path (notmuch);
+    db_path = notmuch_config_get (notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
     db_path_len = strlen (db_path);
 
     relative = path;
diff --git a/lib/message-file.c b/lib/message-file.c
index 311bd478..a23493f1 100644
--- a/lib/message-file.c
+++ b/lib/message-file.c
@@ -64,7 +64,7 @@ _notmuch_message_file_open_ctx (notmuch_database_t *notmuch,
     if (unlikely (message == NULL))
 	return NULL;
 
-    const char *prefix = notmuch_database_get_path (notmuch);
+    const char *prefix = notmuch_config_get (notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
     if (prefix == NULL)
 	goto FAIL;
 
diff --git a/lib/message.cc b/lib/message.cc
index 1bea90f0..35f0b87a 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -1098,7 +1098,7 @@ _notmuch_message_ensure_filename_list (notmuch_message_t *message)
 
 	*colon = '\0';
 
-	db_path = notmuch_database_get_path (message->notmuch);
+	db_path = notmuch_config_get (message->notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
 
 	directory = _notmuch_database_get_directory_path (local,
 							  message->notmuch,
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 0c13f607..8fcd3eed 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -2467,6 +2467,7 @@ notmuch_config_list_destroy (notmuch_config_list_t *config_list);
 typedef enum _notmuch_config_key {
     NOTMUCH_CONFIG_FIRST,
     NOTMUCH_CONFIG_DATABASE_PATH = NOTMUCH_CONFIG_FIRST,
+    NOTMUCH_CONFIG_MAIL_ROOT,
     NOTMUCH_CONFIG_HOOK_DIR,
     NOTMUCH_CONFIG_EXCLUDE_TAGS,
     NOTMUCH_CONFIG_NEW_TAGS,
diff --git a/test/T055-path-config.sh b/test/T055-path-config.sh
new file mode 100755
index 00000000..54c337ef
--- /dev/null
+++ b/test/T055-path-config.sh
@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+test_description='Configuration of mail-root and database path'
+. $(dirname "$0")/test-lib.sh || exit 1
+
+backup_config () {
+    local test_name=$(basename $0 .sh)
+    cp ${NOTMUCH_CONFIG} notmuch-config-backup.${test_name}
+}
+
+restore_config () {
+    local test_name=$(basename $0 .sh)
+    export NOTMUCH_CONFIG="${TMP_DIRECTORY}/notmuch-config"
+    unset CONFIG_PATH
+    unset DATABASE_PATH
+    unset NOTMUCH_PROFILE
+    cp notmuch-config-backup.${test_name} ${NOTMUCH_CONFIG}
+}
+
+split_config () {
+    local dir
+    backup_config
+    dir="$TMP_DIRECTORY/database.$test_count"
+    rm -rf $dir
+    mkdir $dir
+    notmuch config set database.path $dir
+    notmuch config set database.mail_root $MAIL_DIR
+    DATABASE_PATH=$dir
+}
+
+add_email_corpus
+
+for config in traditional split+prefix; do
+    backup_database
+
+    case $config in
+	traditional)
+	    backup_config
+	    ;;
+	split+prefix)
+	    split_config
+	    mv mail/.notmuch $DATABASE_PATH
+	    ;;
+    esac
+
+    test_begin_subtest "count ($config)"
+    output=$(notmuch count '*')
+    test_expect_equal "$output" '52'
+
+    test_begin_subtest "count+tag ($config)"
+    tag="tag${RANDOM}"
+    notmuch tag +$tag '*'
+    output=$(notmuch count tag:$tag)
+    notmuch tag -$tag '*'
+    test_expect_equal "$output" '52'
+
+    restore_config
+    restore_database
+done
+
+test_done
diff --git a/test/T590-libconfig.sh b/test/T590-libconfig.sh
index 4e510e97..5cf70987 100755
--- a/test/T590-libconfig.sh
+++ b/test/T590-libconfig.sh
@@ -364,6 +364,7 @@ EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
 MAIL_DIR
+MAIL_DIR
 MAIL_DIR/.notmuch/hooks
 
 inbox;unread
-- 
2.30.0