Merge pull request #200 from matthiasbeyer/libimagstore/hooks

Libimagstore/hooks

doc/src/04000-lib-store.md

@@ -68,3 +68,99 @@ It also MUST contain a getter for this variable.
 It MUST NOT contain a setter for this variable, as changing the store while the
 programm is running is not allowed.
 
+## Hook system {#sec:libstore:hooks}
+
+The store library includes a hook system, which can be used to execute arbitrary
+code before or after the store was accessed. The following hooks are available:
+
+* `PreReadHook`
+* `PostReadHook`
+* `PreCreateHook`
+* `PostCreateHook`
+* `PreUpdateHook`
+* `PostUpdateHook`
+* `PreDeleteHook`
+* `PostDeleteHook`
+
+These are called "Hook positions" in the following.
+
+Which are executed before or after the store action is executed. The `Pre`-Hooks
+can deny the execution by returning an error. The `Post`-Hooks can (for the
+appropriate store actions) alter the hook result.
+
+Registering hooks with the store is implemented via functions on the `Store`
+type itself. Hooks MUST NEVER be removed from the `Store` object during runtime,
+only adding hooks to the store is allowed.
+
+As the hooks are simply trait objects, one is able to implement arbitrary hooks,
+for example
+
+* Simple consistency-checks for the store
+* Version control system adaption for the store (via git for example)
+* Encryption of store entries (via gnupg for example)
+* Automatic backup on every change to the store (via rsnapshot for example)
+
+Some hooks MAY be shipped with the imag source distribution and be enabled by
+default.
+
+Execution order of the hooks is a not-yet-solved problem.
+
+### Hook-Aspects {#sec:libstore:hooks:aspects}
+
+Each hook can be assigned to an "Aspect". There MAY BE zero or more aspects for
+each Hook position. Aspects can be sorted and configured via the configuration
+file, whereas each aspect has its own configuration section:
+
+```{#lst:hooks:aspects:cfg .toml .numberLines caption="Hook config section"}
+[store]
+
+// Defines order of aspects for the pre-read hook position
+pre-read-aspects  = [ "misc" ]
+
+// Defines order of aspects for the post-read hook position
+post-read-aspects = [ "decryption" ]
+
+// ...
+
+// configuration for the "misc" hook aspect
+[[aspects.misc]]
+parallel-execution = true
+
+// configuration for the "decryption" hook aspect
+[[aspects.decryption]]
+parallel-execution = false
+```
+
+Aspects are executed in the same order they appear in the configuration (in the
+`pre-read-aspects = []` array, for example).
+Aspects _could_ be sorted in different order for each hook position.
+
+Aspect names are unique, so one aspect "misc" in "pre-read-aspects" is the
+same as in "post-read-aspects" and both be configured via `aspects.misc`, though
+they do not share hooks.
+
+Aspects where parallel execution is enabled MAY BE executed in sequence if one
+of the hooks wants mutable access to the data they hook into.
+
+Hooks can then be assigned to one hook aspect. Hooks MUST never be assigned to
+more than one hook aspect. Hooks which are not assigned to any aspect MUST never
+be executed.
+
+```{#lst:hooks:cfg .toml .numberLines caption="Hook configuration"}
+[hooks]
+
+// decrypt hook with gnupg. An appropriate "gnupg-encrypt" hook must be defined
+// to be fully operational, of course
+[[gnupg-decrypt]]
+aspect = "decryption"
+key = "0x123456789"
+
+// version control hook. Sorted into aspect "misc" here.
+[[git]]
+aspect = "misc"
+
+// ...
+```
+
+Hooks MAY HAVE arbitrary configuration keys.
+

libimagrt/src/configuration.rs

@@ -156,6 +156,13 @@ impl Configuration {
         &self.config
     }
 
+    pub fn store_config(&self) -> Option<&Value> {
+        match &self.config {
+            &Value::Table(ref tabl) => tabl.get("store"),
+            _ => None,
+        }
+    }
+
 }
 
 fn get_verbosity(v: &Value) -> bool {

libimagrt/src/runtime.rs

@@ -68,7 +68,14 @@ impl<'a> Runtime<'a> {
             Some(cfg.unwrap())
         };
 
-        Store::new(storepath).map(|store| {
+        let store_config = {
+            match &cfg {
+                &Some(ref c) => c.store_config().map(|c| c.clone()),
+                _ => None
+            }
+        };
+
+        Store::new(storepath, store_config).map(|store| {
             Runtime {
                 cli_matches: matches,
                 configuration: cfg,

libimagstore/Cargo.toml

@@ -12,6 +12,7 @@ regex = "0.1.54"
 semver = "0.2"
 toml = "0.1.25"
 version = "2.0.1"
+crossbeam = "0.2.8"
 
 [dev-dependencies]
 tempdir = "0.3.4"

libimagstore/src/configuration.rs

@@ -0,0 +1,247 @@
+use toml::Value;
+use hook::position::HookPosition;
+
+/// Check whether the configuration is valid for the store
+///
+/// The passed `Value` _must be_ the `[store]` sub-tree of the configuration. Otherwise this will
+/// fail.
+///
+/// It checks whether the configuration looks like the store wants it to be:
+///
+/// ```toml
+/// [store]
+/// pre-create-hook-aspects = [ "misc", "encryption", "version-control"]
+///
+/// [[aspects.misc]]
+/// parallel = true
+/// [[aspects.encryption]]
+/// parallel = false
+/// [[aspects.version-control]]
+/// parallel = false
+///
+/// [[hooks.gnupg]]
+/// aspect = "encryption"
+/// key = "0x123456789"
+///
+/// [[hooks.git]]
+/// aspect = "version-control"
+/// ```
+///
+/// It checks:
+///  * Whether all the maps are there (whether store, store.aspects, store.aspects.example are all
+///  maps)
+///  * Whether each aspect configuration has a "parallel = <Boolean>" setting
+///  * Whether each hook congfiguration has a "aspect = <String>" setting
+///
+/// It does NOT check:
+///  * Whether all aspects which are used in the hook configuration are also configured
+///
+/// No configuration is a valid configuration, as the store will use the most conservative settings
+/// automatically. This has also performance impact, as all hooks run in no-parallel mode then.
+/// You have been warned!
+///
+///
+pub fn config_is_valid(config: &Option<Value>) -> bool {
+    use std::collections::BTreeMap;
+
+    if config.is_none() {
+        return true;
+    }
+
+    fn has_key_with_map(v: &BTreeMap<String, Value>, key: &str) -> bool {
+        v.get(key).map(|t| match t { &Value::Table(_) => true, _ => false }).unwrap_or(false)
+    }
+
+    fn has_key_with_string_ary(v: &BTreeMap<String, Value>, key: &str) -> bool {
+        v.get(key)
+            .map(|t| match t {
+                &Value::Array(ref a) => a.iter().all(|elem| {
+                    match elem {
+                        &Value::String(_) => true,
+                        _ => false,
+                    }
+                }),
+                _ => false
+            }).unwrap_or(false)
+    }
+
+    /// Check that
+    /// * the top-level configuration
+    /// * is a table
+    /// * where all entries of a key `section` (eg. "hooks" or "aspects")
+    ///     * Are maps
+    ///     * where each has a key `key` (eg. "aspect" or "parallel")
+    ///     * which fullfills constraint `f` (typecheck)
+    fn check_all_inner_maps_have_key_with<F>(store_config: &BTreeMap<String, Value>,
+                                             section: &str,
+                                             key: &str,
+                                             f: F)
+        -> bool
+        where F: Fn(&Value) -> bool
+    {
+        store_config.get(section) // The store config has the section `section`
+            .map(|section_table| {
+                match section_table { // which is
+                    &Value::Table(ref section_table) => // a table
+                        section_table
+                            .values() // which has values,
+                            .all(|cfg| { // and all of these values
+                                match cfg {
+                                    &Value::Table(ref hook_config) => { // are tables
+                                        hook_config.get(key) // with a key
+                                            // fullfilling this constraint
+                                            .map(|hook_aspect| f(&hook_aspect))
+                                            .unwrap_or(false)
+                                    },
+                                    _ => false,
+                                }
+                            }),
+                    _ => false,
+                }
+            })
+            .unwrap_or(false)
+    }
+
+    match config {
+        &Some(Value::Table(ref t)) => {
+            has_key_with_string_ary(t, "pre-read-hook-aspects")        &&
+            has_key_with_string_ary(t, "post-read-hook-aspects")       &&
+            has_key_with_string_ary(t, "pre-create-hook-aspects")      &&
+            has_key_with_string_ary(t, "post-create-hook-aspects")     &&
+            has_key_with_string_ary(t, "pre-retrieve-hook-aspects")    &&
+            has_key_with_string_ary(t, "post-retrieve-hook-aspects")   &&
+            has_key_with_string_ary(t, "pre-update-hook-aspects")      &&
+            has_key_with_string_ary(t, "post-update-hook-aspects")     &&
+            has_key_with_string_ary(t, "pre-delete-hook-aspects")      &&
+            has_key_with_string_ary(t, "post-delete-hook-aspects")     &&
+
+            // The section "hooks" has maps which have a key "aspect" which has a value of type
+            // String
+            check_all_inner_maps_have_key_with(t, "hooks", "aspect", |asp| {
+                match asp { &Value::String(_) => true, _ => false }
+            }) &&
+
+            // The section "aspects" has maps which have a key "parllel" which has a value of type
+            // Boolean
+            check_all_inner_maps_have_key_with(t, "aspects", "parallel", |asp| {
+                match asp { &Value::Boolean(_) => true, _ => false, }
+            })
+        }
+        _ => false,
+    }
+}
+
+pub fn get_pre_read_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("pre-read-hook-aspects", value)
+}
+
+pub fn get_post_read_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("post-read-hook-aspects", value)
+}
+
+pub fn get_pre_create_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("pre-create-hook-aspects", value)
+}
+
+pub fn get_post_create_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("post-create-hook-aspects", value)
+}
+
+pub fn get_pre_retrieve_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("pre-retrieve-hook-aspects", value)
+}
+
+pub fn get_post_retrieve_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("post-retrieve-hook-aspects", value)
+}
+
+pub fn get_pre_update_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("pre-update-hook-aspects", value)
+}
+
+pub fn get_post_update_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("post-update-hook-aspects", value)
+}
+
+pub fn get_pre_delete_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("pre-delete-hook-aspects", value)
+}
+
+pub fn get_post_delete_aspect_names(value: &Option<Value>) -> Vec<String> {
+    get_aspect_names_for_aspect_position("post-delete-hook-aspects", value)
+}
+
+#[derive(Debug)]
+pub struct AspectConfig {
+    parallel: bool,
+    config: Value,
+}
+
+impl AspectConfig {
+
+    pub fn new(init: Value) -> AspectConfig {
+        let parallel = AspectConfig::is_parallel(&init);
+        AspectConfig {
+            config: init,
+            parallel: parallel,
+        }
+    }
+
+    pub fn config(&self) -> &Value {
+        &self.config
+    }
+
+    fn is_parallel(init: &Value) -> bool {
+        match init {
+            &Value::Table(ref t) =>
+                t.get("parallel")
+                    .map(|value| {
+                        match value {
+                            &Value::Boolean(b) => b,
+                            _ => false,
+                        }
+                    })
+                    .unwrap_or(false),
+            _ => false,
+        }
+    }
+
+    /// Get the aspect configuration for an aspect.
+    ///
+    /// Pass the store configuration object, this searches in `[aspects][<aspect_name>]`.
+    ///
+    /// Returns `None` if one of the keys in the chain is not available
+    pub fn get_for(v: &Option<Value>, a_name: String) -> Option<AspectConfig> {
+        match v {
+            &Some(Value::Table(ref tabl)) => tabl.get(&a_name[..])
+                .map(|asp| AspectConfig::new(asp.clone())),
+            _ => None,
+        }
+    }
+
+}
+
+fn get_aspect_names_for_aspect_position(config_name: &'static str, value: &Option<Value>) -> Vec<String> {
+    let mut v = vec![];
+
+    match value {
+        &Some(Value::Table(ref t)) => {
+            match t.get(config_name) {
+                Some(&Value::Array(ref a)) => {
+                    for elem in a {
+                        match elem {
+                            &Value::String(ref s) => v.push(s.clone()),
+                            _ => warn!("Non-String in configuration, inside '{}'", config_name),
+                        }
+                    }
+                },
+                _ => warn!("'{}' configuration key should contain Array, does not", config_name),
+            };
+        },
+        &None => warn!("No store configuration"),
+        _ => warn!("Configuration is not a table"),
+    }
+    v
+}
+
+

libimagstore/src/error.rs

@@ -10,6 +10,7 @@ use std::convert::From;
  */
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum StoreErrorKind {
+    ConfigurationError,
     FileError,
     IdLocked,
     IdNotFound,
@@ -27,11 +28,16 @@ pub enum StoreErrorKind {
     HeaderPathTypeFailure,
     HeaderKeyNotFound,
     HeaderTypeFailure,
+    HookRegisterError,
+    HookExecutionError,
+    PreHookExecuteError,
+    PostHookExecuteError,
         // maybe more
 }
 
 fn store_error_type_as_str(e: &StoreErrorKind) -> &'static str {
     match e {
+        &StoreErrorKind::ConfigurationError => "Store Configuration Error",
         &StoreErrorKind::FileError       => "File Error",
         &StoreErrorKind::IdLocked        => "ID locked",
         &StoreErrorKind::IdNotFound      => "ID not found",
@@ -50,6 +56,10 @@ fn store_error_type_as_str(e: &StoreErrorKind) -> &'static str {
         &StoreErrorKind::HeaderPathTypeFailure => "Header has wrong type for path",
         &StoreErrorKind::HeaderKeyNotFound     => "Header Key not found",
         &StoreErrorKind::HeaderTypeFailure     => "Header type is wrong",
+        &StoreErrorKind::HookRegisterError     => "Hook register error",
+        &StoreErrorKind::HookExecutionError    => "Hook execution error",
+        &StoreErrorKind::PreHookExecuteError   => "Pre-Hook execution error",
+        &StoreErrorKind::PostHookExecuteError  => "Post-Hook execution error",
     }
 }
 

libimagstore/src/hook/accessor.rs

@@ -0,0 +1,27 @@
+use hook::result::HookResult;
+use store::FileLockEntry;
+use storeid::StoreId;
+
+pub trait StoreIdAccessor : Send + Sync {
+    fn access(&self, &StoreId) -> HookResult<()>;
+}
+
+pub trait MutableHookDataAccessor : Send + Sync {
+    fn access_mut(&self, &mut FileLockEntry) -> HookResult<()>;
+}
+
+pub trait NonMutableHookDataAccessor : Send + Sync {
+    fn access(&self, &FileLockEntry) -> HookResult<()>;
+}
+
+pub enum HookDataAccessor<'a> {
+    StoreIdAccess(&'a StoreIdAccessor),
+    MutableAccess(&'a MutableHookDataAccessor),
+    NonMutableAccess(&'a NonMutableHookDataAccessor),
+}
+
+pub trait HookDataAccessorProvider {
+    fn accessor(&self) -> HookDataAccessor;
+}
+
+

libimagstore/src/hook/aspect.rs

@@ -0,0 +1,144 @@
+use store::FileLockEntry;
+use storeid::StoreId;
+use hook::Hook;
+use hook::result::HookResult;
+use hook::accessor::{StoreIdAccessor, MutableHookDataAccessor, NonMutableHookDataAccessor};
+use hook::accessor::HookDataAccessor as HDA;
+
+use hook::error::HookError as HE;
+use hook::error::HookErrorKind as HEK;
+use configuration::AspectConfig;
+
+#[derive(Debug)]
+pub struct Aspect {
+    cfg: Option<AspectConfig>,
+    name: String,
+    hooks: Vec<Box<Hook>>,
+}
+
+impl Aspect {
+
+    pub fn new(name: String, cfg: Option<AspectConfig>) -> Aspect {
+        Aspect {
+            cfg: cfg,
+            name: name,
+            hooks: vec![],
+        }
+    }
+
+    pub fn name(&self) -> &String {
+        &self.name
+    }
+
+    pub fn register_hook(&mut self, h: Box<Hook>) {
+        self.hooks.push(h);
+    }
+
+}
+
+impl StoreIdAccessor for Aspect {
+    fn access(&self, id: &StoreId) -> HookResult<()> {
+        use crossbeam;
+        use std::thread;
+        use std::thread::JoinHandle;
+
+        let accessors : Vec<HDA> = self.hooks.iter().map(|h| h.accessor()).collect();
+        if !accessors.iter().all(|a| match a { &HDA::StoreIdAccess(_)  => true, _ => false }) {
+            return Err(HE::new(HEK::AccessTypeViolation, None));
+        }
+
+        let threads : Vec<HookResult<()>> = accessors
+            .iter()
+            .map(|accessor| {
+                crossbeam::scope(|scope| {
+                    scope.spawn(|| {
+                        match accessor {
+                            &HDA::StoreIdAccess(accessor) => accessor.access(id),
+                            _ => unreachable!(),
+                        }
+                        .map_err(|e| ()) // TODO: We're losing the error cause here
+                    })
+                })
+            })
+            .map(|i| i.join().map_err(|_| HE::new(HEK::HookExecutionError, None)))
+            .collect();
+
+        threads
+            .into_iter()
+            .fold(Ok(()), |acc, elem| {
+                acc.and_then(|a| {
+                    elem.map(|_| a).map_err(|_| HE::new(HEK::HookExecutionError, None))
+                })
+            })
+    }
+}
+
+impl MutableHookDataAccessor for Aspect {
+    fn access_mut(&self, fle: &mut FileLockEntry) -> HookResult<()> {
+        let accessors : Vec<HDA> = self.hooks.iter().map(|h| h.accessor()).collect();
+
+        fn is_file_accessor(a: &HDA) -> bool {
+            match a {
+                &HDA::MutableAccess(_)  => true,
+                &HDA::NonMutableAccess(_)  => true,
+                _ => false,
+            }
+        }
+
+        if !accessors.iter().all(|a| is_file_accessor(a)) {
+            return Err(HE::new(HEK::AccessTypeViolation, None));
+        }
+
+        for accessor in accessors {
+            match accessor {
+                HDA::MutableAccess(accessor)    => try!(accessor.access_mut(fle)),
+
+                // TODO: Naiive implementation.
+                // More sophisticated version would check whether there are _chunks_ of
+                // NonMutableAccess accessors and execute these chunks in parallel. We do not have
+                // performance concerns yet, so this is okay.
+                HDA::NonMutableAccess(accessor) => try!(accessor.access(fle)),
+                _ => unreachable!(),
+            }
+        }
+        Ok(())
+    }
+}
+
+impl NonMutableHookDataAccessor for Aspect {
+    fn access(&self, fle: &FileLockEntry) -> HookResult<()> {
+        use crossbeam;
+        use std::thread;
+        use std::thread::JoinHandle;
+
+        let accessors : Vec<HDA> = self.hooks.iter().map(|h| h.accessor()).collect();
+        if !accessors.iter().all(|a| match a { &HDA::NonMutableAccess(_)  => true, _ => false }) {
+            return Err(HE::new(HEK::AccessTypeViolation, None));
+        }
+
+        let threads : Vec<HookResult<()>> = accessors
+            .iter()
+            .map(|accessor| {
+                crossbeam::scope(|scope| {
+                    scope.spawn(|| {
+                        match accessor {
+                            &HDA::NonMutableAccess(accessor) => accessor.access(fle),
+                            _ => unreachable!(),
+                        }
+                        .map_err(|e| ()) // TODO: We're losing the error cause here
+                    })
+                })
+            })
+            .map(|i| i.join().map_err(|_| HE::new(HEK::HookExecutionError, None)))
+            .collect();
+
+        threads
+            .into_iter()
+            .fold(Ok(()), |acc, elem| {
+                acc.and_then(|a| {
+                    elem.map(|_| a).map_err(|_| HE::new(HEK::HookExecutionError, None))
+                })
+            })
+    }
+}
+

libimagstore/src/hook/error.rs

@@ -0,0 +1,105 @@
+use std::error::Error;
+use std::fmt::Error as FmtError;
+use std::clone::Clone;
+use std::fmt::{Display, Formatter};
+use std::convert::Into;
+
+/**
+ * Kind of error
+ */
+#[derive(Clone, Copy, Debug)]
+pub enum HookErrorKind {
+    HookExecutionError,
+    AccessTypeViolation,
+}
+
+pub trait IntoHookError {
+    fn into_hookerror(self) -> HookError;
+    fn into_hookerror_with_cause(self, cause: Box<Error>) -> HookError;
+}
+
+impl Into<HookError> for HookErrorKind {
+
+    fn into(self) -> HookError {
+        HookError::new(self, None)
+    }
+
+}
+
+impl Into<HookError> for (HookErrorKind, Box<Error>) {
+
+    fn into(self) -> HookError {
+        HookError::new(self.0, Some(self.1))
+    }
+
+}
+
+fn hook_error_type_as_str(e: &HookErrorKind) -> &'static str {
+    match e {
+        _ => "",
+    }
+}
+
+impl Display for HookErrorKind {
+
+    fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> {
+        try!(write!(fmt, "{}", hook_error_type_as_str(self)));
+        Ok(())
+    }
+
+}
+
+/**
+ * Error type
+ */
+#[derive(Debug)]
+pub struct HookError {
+    err_type: HookErrorKind,
+    cause: Option<Box<Error>>,
+}
+
+impl HookError {
+
+    /**
+     * Build a new HookError from an HookErrorKind, optionally with cause
+     */
+    pub fn new(errtype: HookErrorKind, cause: Option<Box<Error>>)
+        -> HookError
+        {
+            HookError {
+                err_type: errtype,
+                cause: cause,
+            }
+        }
+
+    /**
+     * Get the error type of this HookError
+     */
+    pub fn err_type(&self) -> HookErrorKind {
+        self.err_type.clone()
+    }
+
+}
+
+impl Display for HookError {
+
+    fn fmt(&self, fmt: &mut Formatter) -> Result<(), FmtError> {
+        try!(write!(fmt, "[{}]", hook_error_type_as_str(&self.err_type.clone())));
+        Ok(())
+    }
+
+}
+
+impl Error for HookError {
+
+    fn description(&self) -> &str {
+        hook_error_type_as_str(&self.err_type.clone())
+    }
+
+    fn cause(&self) -> Option<&Error> {
+        self.cause.as_ref().map(|e| &**e)
+    }
+
+}
+
+

libimagstore/src/hook/mod.rs

@@ -0,0 +1,20 @@
+use std::fmt::Debug;
+
+use toml::Value;
+
+use self::error::HookError;
+use store::FileLockEntry;
+
+pub mod accessor;
+pub mod aspect;
+pub mod error;
+pub mod position;
+pub mod result;
+
+use hook::accessor::HookDataAccessorProvider;
+
+pub trait Hook : HookDataAccessorProvider + Debug + Send + Sync {
+    fn name(&self) -> &'static str;
+    fn set_config(&mut self, cfg: &Value);
+}
+

libimagstore/src/hook/position.rs

@@ -0,0 +1,13 @@
+#[derive(Debug)]
+pub enum HookPosition {
+    PreRead,
+    PostRead,
+    PreCreate,
+    PostCreate,
+    PreRetrieve,
+    PostRetrieve,
+    PreUpdate,
+    PostUpdate,
+    PreDelete,
+    PostDelete,
+}

libimagstore/src/hook/result.rs

@@ -0,0 +1,3 @@
+use hook::error::HookError;
+
+pub type HookResult<T> = Result<T, HookError>;

libimagstore/src/lib.rs

@@ -7,9 +7,12 @@ extern crate regex;
 extern crate toml;
 #[cfg(test)] extern crate tempdir;
 extern crate semver;
+extern crate crossbeam;
 
 pub mod storeid;
 pub mod error;
+pub mod hook;
 pub mod store;
+mod configuration;
 mod lazyfile;
 

libimagstore/src/store.rs

@@ -9,15 +9,30 @@ use std::collections::BTreeMap;
 use std::io::{Seek, SeekFrom};
 use std::convert::From;
 use std::convert::Into;
+use std::sync::Mutex;
+use std::ops::Deref;
+use std::ops::DerefMut;
 
 use toml::{Table, Value};
 use regex::Regex;
+use crossbeam;
+use crossbeam::ScopedJoinHandle;
 
 use error::{ParserErrorKind, ParserError};
 use error::{StoreError, StoreErrorKind};
 use storeid::{StoreId, StoreIdIterator};
 use lazyfile::LazyFile;
 
+use hook::aspect::Aspect;
+use hook::result::HookResult;
+use hook::accessor::{ MutableHookDataAccessor,
+            NonMutableHookDataAccessor,
+            StoreIdAccessor,
+            HookDataAccessor,
+            HookDataAccessorProvider};
+use hook::position::HookPosition;
+use hook::Hook;
+
 /// The Result Type returned by any interaction with the store that could fail
 pub type Result<T> = RResult<T, StoreError>;
 
@@ -90,6 +105,26 @@ impl StoreEntry {
 pub struct Store {
     location: PathBuf,
 
+    /**
+     * Configuration object of the store
+     */
+    configuration: Option<Value>,
+
+    /*
+     * Registered hooks
+     */
+
+    pre_read_aspects      : Arc<Mutex<Vec<Aspect>>>,
+    post_read_aspects     : Arc<Mutex<Vec<Aspect>>>,
+    pre_create_aspects    : Arc<Mutex<Vec<Aspect>>>,
+    post_create_aspects   : Arc<Mutex<Vec<Aspect>>>,
+    pre_retrieve_aspects  : Arc<Mutex<Vec<Aspect>>>,
+    post_retrieve_aspects : Arc<Mutex<Vec<Aspect>>>,
+    pre_update_aspects    : Arc<Mutex<Vec<Aspect>>>,
+    post_update_aspects   : Arc<Mutex<Vec<Aspect>>>,
+    pre_delete_aspects    : Arc<Mutex<Vec<Aspect>>>,
+    post_delete_aspects   : Arc<Mutex<Vec<Aspect>>>,
+
     /**
      * Internal Path->File cache map
      *
@@ -103,8 +138,14 @@ pub struct Store {
 impl Store {
 
     /// Create a new Store object
-    pub fn new(location: PathBuf) -> Result<Store> {
+    pub fn new(location: PathBuf, store_config: Option<Value>) -> Result<Store> {
         use std::fs::create_dir_all;
+        use configuration::*;
+
+        debug!("Validating Store configuration");
+        if !config_is_valid(&store_config) {
+            return Err(StoreError::new(StoreErrorKind::ConfigurationError, None));
+        }
 
         debug!("Building new Store object");
         if !location.exists() {
@@ -122,11 +163,84 @@ impl Store {
             }
         }
 
-        debug!("Store building succeeded");
-        Ok(Store {
+        let pre_read_aspects = get_pre_read_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let post_read_aspects = get_post_read_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let pre_create_aspects = get_pre_create_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let post_create_aspects = get_post_create_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let pre_retrieve_aspects = get_pre_retrieve_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let post_retrieve_aspects = get_post_retrieve_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let pre_update_aspects = get_pre_update_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let post_update_aspects = get_post_update_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let pre_delete_aspects = get_pre_delete_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let post_delete_aspects = get_post_delete_aspect_names(&store_config)
+            .into_iter().map(|n| {
+                let cfg = AspectConfig::get_for(&store_config, n.clone());
+                Aspect::new(n, cfg)
+            }).collect();
+
+        let store = Store {
             location: location,
+            configuration: store_config,
+            pre_read_aspects      : Arc::new(Mutex::new(pre_read_aspects)),
+            post_read_aspects     : Arc::new(Mutex::new(post_read_aspects)),
+            pre_create_aspects    : Arc::new(Mutex::new(pre_create_aspects)),
+            post_create_aspects   : Arc::new(Mutex::new(post_create_aspects)),
+            pre_retrieve_aspects  : Arc::new(Mutex::new(pre_retrieve_aspects)),
+            post_retrieve_aspects : Arc::new(Mutex::new(post_retrieve_aspects)),
+            pre_update_aspects    : Arc::new(Mutex::new(pre_update_aspects)),
+            post_update_aspects   : Arc::new(Mutex::new(post_update_aspects)),
+            pre_delete_aspects    : Arc::new(Mutex::new(pre_delete_aspects)),
+            post_delete_aspects   : Arc::new(Mutex::new(post_delete_aspects)),
             entries: Arc::new(RwLock::new(HashMap::new())),
-        })
+        };
+
+        debug!("Store building succeeded");
+        Ok(store)
     }
 
     fn storify_id(&self, id: StoreId) -> StoreId {
@@ -140,6 +254,10 @@ impl Store {
     /// Creates the Entry at the given location (inside the entry)
     pub fn create<'a>(&'a self, id: StoreId) -> Result<FileLockEntry<'a>> {
         let id = self.storify_id(id);
+        if let Err(e) = self.execute_hooks_for_id(self.pre_create_aspects.clone(), &id) {
+            return Err(e);
+        }
+
         let hsmap = self.entries.write();
         if hsmap.is_err() {
             return Err(StoreError::new(StoreErrorKind::LockPoisoned, None))
@@ -153,13 +271,21 @@ impl Store {
             se.status = StoreEntryStatus::Borrowed;
             se
         });
-        Ok(FileLockEntry::new(self, Entry::new(id.clone()), id))
+
+        let mut fle = FileLockEntry::new(self, Entry::new(id.clone()), id);
+        self.execute_hooks_for_mut_file(self.post_create_aspects.clone(), &mut fle)
+            .map_err(|e| StoreError::new(StoreErrorKind::PostHookExecuteError, Some(Box::new(e))))
+            .map(|_| fle)
     }
 
     /// Borrow a given Entry. When the `FileLockEntry` is either `update`d or
     /// dropped, the new Entry is written to disk
     pub fn retrieve<'a>(&'a self, id: StoreId) -> Result<FileLockEntry<'a>> {
         let id = self.storify_id(id);
+        if let Err(e) = self.execute_hooks_for_id(self.pre_retrieve_aspects.clone(), &id) {
+            return Err(e);
+        }
+
         self.entries
             .write()
             .map_err(|_| StoreError::new(StoreErrorKind::LockPoisoned, None))
@@ -170,6 +296,14 @@ impl Store {
                 entry
             })
             .map(|e| FileLockEntry::new(self, e, id))
+            .and_then(|mut fle| {
+                if let Err(e) = self.execute_hooks_for_mut_file(self.pre_retrieve_aspects.clone(), &mut fle) {
+                    Err(StoreError::new(StoreErrorKind::HookExecutionError, Some(Box::new(e))))
+                } else {
+                    Ok(fle)
+                }
+
+            })
    }
 
     /// Iterate over all StoreIds for one module name
@@ -178,8 +312,16 @@ impl Store {
     }
 
     /// Return the `FileLockEntry` and write to disk
-    pub fn update<'a>(&'a self, entry: FileLockEntry<'a>) -> Result<()> {
-        self._update(&entry)
+    pub fn update<'a>(&'a self, mut entry: FileLockEntry<'a>) -> Result<()> {
+        if let Err(e) = self.execute_hooks_for_mut_file(self.pre_update_aspects.clone(), &mut entry) {
+            return Err(e);
+        }
+
+        if let Err(e) = self._update(&entry) {
+            return Err(e);
+        }
+
+        self.execute_hooks_for_mut_file(self.post_update_aspects.clone(), &mut entry)
     }
 
     /// Internal method to write to the filesystem store.
@@ -230,7 +372,11 @@ impl Store {
     /// Delete an entry
     pub fn delete(&self, id: StoreId) -> Result<()> {
         let id = self.storify_id(id);
-        let mut entries_lock = self.entries.write();
+        if let Err(e) = self.execute_hooks_for_id(self.pre_delete_aspects.clone(), &id) {
+            return Err(e);
+        }
+
+        let entries_lock = self.entries.write();
         if entries_lock.is_err() {
             return Err(StoreError::new(StoreErrorKind::LockPoisoned, None))
         }
@@ -244,7 +390,11 @@ impl Store {
 
         // remove the entry first, then the file
         entries.remove(&id);
-        remove_file(&id).map_err(|e| StoreError::new(StoreErrorKind::FileError, Some(Box::new(e))))
+        if let Err(e) = remove_file(&id) {
+            return Err(StoreError::new(StoreErrorKind::FileError, Some(Box::new(e))));
+        }
+
+        self.execute_hooks_for_id(self.post_delete_aspects.clone(), &id)
     }
 
     /// Gets the path where this store is on the disk
@@ -252,6 +402,113 @@ impl Store {
         &self.location
     }
 
+    pub fn register_hook(&mut self,
+                         position: HookPosition,
+                         aspect_name: &String,
+                         mut h: Box<Hook>)
+        -> Result<()>
+    {
+        debug!("Registering hook: {:?}", h);
+        debug!("     in position: {:?}", position);
+        debug!("     with aspect: {:?}", aspect_name);
+
+        let mut guard = match position {
+                HookPosition::PreRead      => self.pre_read_aspects.clone(),
+                HookPosition::PostRead     => self.post_read_aspects.clone(),
+                HookPosition::PreCreate    => self.pre_create_aspects.clone(),
+                HookPosition::PostCreate   => self.post_create_aspects.clone(),
+                HookPosition::PreRetrieve  => self.pre_retrieve_aspects.clone(),
+                HookPosition::PostRetrieve => self.post_retrieve_aspects.clone(),
+                HookPosition::PreUpdate    => self.pre_update_aspects.clone(),
+                HookPosition::PostUpdate   => self.post_update_aspects.clone(),
+                HookPosition::PreDelete    => self.pre_delete_aspects.clone(),
+                HookPosition::PostDelete   => self.post_delete_aspects.clone(),
+            };
+
+        let mut guard = guard
+            .deref()
+            .lock()
+            .map_err(|_| StoreError::new(StoreErrorKind::HookRegisterError, None));
+
+        if guard.is_err() {
+            return Err(StoreError::new(StoreErrorKind::HookRegisterError,
+                                       Some(Box::new(guard.err().unwrap()))));
+        }
+        let mut guard  = guard.unwrap();
+        for mut aspect in guard.deref_mut() {
+            if aspect.name().clone() == aspect_name.clone() {
+                self.get_config_for_hook(h.name()).map(|config| h.set_config(config));
+                aspect.register_hook(h);
+                return Ok(());
+            }
+        }
+        return Err(StoreError::new(StoreErrorKind::HookRegisterError, None));
+    }
+
+    fn get_config_for_hook(&self, name: &str) -> Option<&Value> {
+        match &self.configuration {
+            &Some(Value::Table(ref tabl)) => {
+                tabl.get("hooks")
+                    .map(|hook_section| {
+                        match hook_section {
+                            &Value::Table(ref tabl) => tabl.get(name),
+                            _ => None
+                        }
+                    })
+                    .unwrap_or(None)
+            },
+            _ => None,
+        }
+    }
+
+    fn execute_hooks_for_id(&self,
+                            aspects: Arc<Mutex<Vec<Aspect>>>,
+                            id: &StoreId)
+        -> Result<()>
+    {
+        let guard = aspects.deref().lock();
+        if guard.is_err() { return Err(StoreError::new(StoreErrorKind::PreHookExecuteError, None)) }
+
+        guard.unwrap().deref().iter()
+            .fold(Ok(()), |acc, aspect| {
+                debug!("[Aspect][exec]: {:?}", aspect);
+                acc.and_then(|_| (aspect as &StoreIdAccessor).access(id))
+            })
+            .map_err(|e| StoreError::new(StoreErrorKind::PreHookExecuteError, Some(Box::new(e))))
+    }
+
+    fn execute_hooks_for_mut_file(&self,
+                                  aspects: Arc<Mutex<Vec<Aspect>>>,
+                                  fle: &mut FileLockEntry)
+        -> Result<()>
+    {
+        let guard = aspects.deref().lock();
+        if guard.is_err() { return Err(StoreError::new(StoreErrorKind::PreHookExecuteError, None)) }
+
+        guard.unwrap().deref().iter()
+            .fold(Ok(()), |acc, aspect| {
+                debug!("[Aspect][exec]: {:?}", aspect);
+                acc.and_then(|_| aspect.access_mut(fle))
+            })
+            .map_err(|e| StoreError::new(StoreErrorKind::PreHookExecuteError, Some(Box::new(e))))
+    }
+
+    fn execute_hooks_for_file(&self,
+                              aspects: Arc<Mutex<Vec<Aspect>>>,
+                              fle: &FileLockEntry)
+        -> Result<()>
+    {
+        let guard = aspects.deref().lock();
+        if guard.is_err() { return Err(StoreError::new(StoreErrorKind::PreHookExecuteError, None)) }
+
+        guard.unwrap().deref().iter()
+            .fold(Ok(()), |acc, aspect| {
+                debug!("[Aspect][exec]: {:?}", aspect);
+                acc.and_then(|_| (aspect as &NonMutableHookDataAccessor).access(fle))
+            })
+            .map_err(|e| StoreError::new(StoreErrorKind::PreHookExecuteError, Some(Box::new(e))))
+    }
+
 }
 
 impl Drop for Store {