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Will
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watcher-nodejs: first draft of the watcher, for node js
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10 files changed

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10 files changed

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lines changed

‎libcwatcher/src/watcher-cabi.cpp

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@@ -38,7 +38,7 @@ void* wtr_watcher_open(
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{
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auto wrapped_callback = [callback, context](wtr::watcher::event ev_owned)
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{
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wtr_watcher_event ev_view = {0};
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wtr_watcher_event ev_view = {};
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#ifdef _WIN32
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char path_name[PATH_BUF_LEN] = {0};
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char associated_path_name[PATH_BUF_LEN] = {0};

‎watcher-nodejs/.clang-format

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AccessModifierOffset: -2
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AlignAfterOpenBracket: AlwaysBreak
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AlignArrayOfStructures: Right
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# AlignConsecutiveAssignments: None
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AlignConsecutiveBitFields:
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Enabled: true
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AcrossEmptyLines: true
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AcrossComments: true
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# AlignConsecutiveDeclarations: None
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# AlignConsecutiveMacros
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AlignEscapedNewlines: Left
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AlignOperands: AlignAfterOperator
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AlignTrailingComments: true
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# [v16+]
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# AlignTrailingComments:
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# Kind: Always
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# OverEmptyLines: 2
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AllowAllArgumentsOnNextLine: false
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AllowAllParametersOfDeclarationOnNextLine: false
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AllowShortBlocksOnASingleLine: Always # Empty
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AllowShortCaseLabelsOnASingleLine: true
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AllowShortEnumsOnASingleLine: true
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AllowShortFunctionsOnASingleLine: All # Empty
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AllowShortIfStatementsOnASingleLine: Never
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AllowShortLambdasOnASingleLine: All # Empty
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AllowShortLoopsOnASingleLine: true
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AlwaysBreakAfterReturnType: None
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AlwaysBreakBeforeMultilineStrings: false
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AlwaysBreakTemplateDeclarations: Yes
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BinPackArguments: false
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BinPackParameters: false
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BitFieldColonSpacing: Both
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# [v16+]
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# BreakAfterAttributes: Always
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BreakBeforeBinaryOperators: NonAssignment # All
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# break before function scope (incl. lambdas) and else statements
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BreakBeforeBraces: Custom
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BraceWrapping:
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AfterCaseLabel: false
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AfterClass: false
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# [v16+]
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AfterControlStatement: Never
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AfterEnum: false
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AfterFunction: true
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AfterNamespace: false
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AfterObjCDeclaration: false
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AfterStruct: false
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AfterUnion: false
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AfterExternBlock: false
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BeforeCatch: false
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BeforeElse: false
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BeforeLambdaBody: true
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BeforeWhile: false
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IndentBraces: false
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SplitEmptyFunction: false
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SplitEmptyRecord: false
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SplitEmptyNamespace: false
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BreakBeforeConceptDeclarations: Always
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BreakBeforeTernaryOperators: true
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BreakConstructorInitializers: BeforeComma
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BreakInheritanceList: BeforeColon
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BreakStringLiterals: true
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ColumnLimit: 120
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# CommentPragmas regex
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CompactNamespaces: false
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ContinuationIndentWidth: 2
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Cpp11BracedListStyle: true
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EmptyLineAfterAccessModifier: Never
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EmptyLineBeforeAccessModifier: Always
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FixNamespaceComments: false
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IncludeBlocks: Merge
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# IncludeCategories regex [maybe useful for tool/hone]
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IndentAccessModifiers: false
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IndentCaseBlocks: false
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IndentCaseLabels: true
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IndentExternBlock: false
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IndentGotoLabels: true
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# IndentPPDirectives: BeforeHash [messes up includes, nice w/modules]
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IndentRequiresClause: false
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IndentWidth: 2
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# [v16+]
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# InsertNewlineAtEOF: true
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# [v16+]
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# IntegerLiteralSeparator:
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# Binary: 4
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# Decimal: 3
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# Hex: 2
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# [v16+]
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# LineEnding: LF
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NamespaceIndentation: None
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PackConstructorInitializers: Never
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PenaltyBreakOpenParenthesis: 0
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PenaltyBreakBeforeFirstCallParameter: 0
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PointerAlignment: Left
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QualifierAlignment: Custom
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# [bad docs? 'friend' does not work]
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QualifierOrder: ['inline', 'static', 'constexpr', 'volatile', 'restrict', 'type', 'const']
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ReferenceAlignment: Left
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ReflowComments: true
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RequiresClausePosition: OwnLine
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# [v16+]
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# RequiresExpressionIndentation: OuterScope
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SeparateDefinitionBlocks: Always
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SortIncludes: CaseInsensitive
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# SortIncludes: true
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# [bad docs?]
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# SortUsingDeclarations: LexicographicNumeric
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SortUsingDeclarations: true
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SpaceAfterCStyleCast: false
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SpaceAfterLogicalNot: true # false
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SpaceAfterTemplateKeyword: false
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SpaceBeforeAssignmentOperators: true
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SpaceBeforeCaseColon: true
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SpaceBeforeCpp11BracedList: false # true
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SpaceBeforeRangeBasedForLoopColon: true
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SpaceBeforeSquareBrackets: false # true
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SpaceInEmptyBlock: false
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SpaceInEmptyParentheses: false
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SpacesBeforeTrailingComments: 2
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SpacesInConditionalStatement: false
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SpacesInContainerLiterals: true
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SpacesInAngles: Never
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SpacesInCStyleCastParentheses: false
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# SpacesInLineCommentPrefix
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SpacesInSquareBrackets: false
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Standard: Latest
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SpaceBeforeCtorInitializerColon: true
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SpaceBeforeInheritanceColon: true
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SpaceBeforeParens: ControlStatements # Never
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TabWidth: 2
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UseTab: Never

‎watcher-nodejs/.gitignore

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build
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node_modules

‎watcher-nodejs/binding.gyp

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{
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"targets": [
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{
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"target_name": "watcher",
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"sources": [
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"../libcwatcher/src/watcher-cabi.cpp",
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"cwatcher_wrapper.cpp",
8+
],
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"include_dirs": [
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"../libcwatcher/include",
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],
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"link_settings": {
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"libraries": [
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"-Wl,-rpath,/usr/local/lib",
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]
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}
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}
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]
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}
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‎watcher-nodejs/cwatcher_wrapper.cpp

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#define NAPI_VERSION 8
2+
#include "wtr/watcher-cabi.h"
3+
#include <node_api.h>
4+
#include <stdio.h>
5+
#include <stdlib.h>
6+
#include <string.h>
7+
8+
#define WITH_TSFN_NONBLOCKING 1
9+
10+
/* Owns:
11+
- A "handle" to a watch object,
12+
which we can give back to the watcher
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when we want to close it.
14+
- A (thread-safe) function, storing the
15+
user's callback, which we can call when
16+
an event is ready.
17+
- A reference to the user's callback, which
18+
we release when the watcher is closed. */
19+
struct WatcherWrapper {
20+
napi_ref js_callback_ref = NULL;
21+
napi_threadsafe_function tsfn = NULL;
22+
void* watcher = NULL;
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};
24+
25+
/* Called by the callback bridge when an event is ready.
26+
Forwards event to js-land for the user.
27+
Expects an "owned" event, which will be freed in this scope. */
28+
static void callback_js_receiver(napi_env env, napi_value js_callback, void* _unused, void* ctx)
29+
{
30+
wtr_watcher_event* event = (wtr_watcher_event*)ctx;
31+
napi_value event_obj;
32+
napi_create_object(env, &event_obj);
33+
napi_value path_name, effect_type, path_type, effect_time, associated_path_name;
34+
napi_create_string_utf8(env, event->path_name, NAPI_AUTO_LENGTH, &path_name);
35+
napi_create_int32(env, event->effect_type, &effect_type);
36+
napi_create_int32(env, event->path_type, &path_type);
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napi_create_bigint_int64(env, event->effect_time, &effect_time);
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napi_set_named_property(env, event_obj, "pathName", path_name);
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napi_set_named_property(env, event_obj, "effectType", effect_type);
40+
napi_set_named_property(env, event_obj, "pathType", path_type);
41+
napi_set_named_property(env, event_obj, "effectTime", effect_time);
42+
if (event->associated_path_name) {
43+
napi_create_string_utf8(env, event->associated_path_name, NAPI_AUTO_LENGTH, &associated_path_name);
44+
napi_set_named_property(env, event_obj, "associatedPathName", associated_path_name);
45+
}
46+
napi_value global;
47+
napi_get_global(env, &global);
48+
napi_value result;
49+
napi_call_function(env, global, js_callback, 1, &event_obj, &result);
50+
#if WITH_TSFN_NONBLOCKING
51+
free((void*)event->path_name);
52+
free((void*)event->associated_path_name);
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free(event);
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#endif
55+
}
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/* Called by the watcher when an event is ready.
58+
Passes a newly allocated event to the wrapper's stored function.
59+
Expects the event it to be freed in the wrapper's stored function. */
60+
static void callback_bridge(struct wtr_watcher_event event_view, void* ctx)
61+
{
62+
WatcherWrapper* wrapper = (WatcherWrapper*)ctx;
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#if WITH_TSFN_NONBLOCKING
64+
wtr_watcher_event* event_owned = (wtr_watcher_event*)malloc(sizeof(wtr_watcher_event));
65+
event_owned->path_name = event_view.path_name ? strdup(event_view.path_name) : NULL;
66+
event_owned->effect_type = event_view.effect_type;
67+
event_owned->path_type = event_view.path_type;
68+
event_owned->effect_time = event_view.effect_time;
69+
event_owned->associated_path_name = event_view.associated_path_name ? strdup(event_view.associated_path_name) : NULL;
70+
if (wrapper->tsfn) {
71+
napi_call_threadsafe_function(wrapper->tsfn, event_owned, napi_tsfn_nonblocking);
72+
#else
73+
napi_call_threadsafe_function(wrapper->tsfn, &event_view, napi_tsfn_blocking);
74+
#endif
75+
}
76+
}
77+
78+
/* Should be called by the user when they are done with the watcher.
79+
Ends event processing and releases any owned resources. */
80+
static napi_value close(napi_env env, napi_callback_info func_arg_info)
81+
{
82+
void* ctx;
83+
napi_get_cb_info(env, func_arg_info, NULL, NULL, NULL, &ctx);
84+
WatcherWrapper* wrapper = (WatcherWrapper*)ctx;
85+
if (wrapper->tsfn) {
86+
napi_release_threadsafe_function(wrapper->tsfn, napi_tsfn_release);
87+
wrapper->tsfn = NULL;
88+
}
89+
if (wrapper->js_callback_ref) {
90+
napi_delete_reference(env, wrapper->js_callback_ref);
91+
wrapper->js_callback_ref = NULL;
92+
}
93+
bool closed_ok = wtr_watcher_close(wrapper->watcher);
94+
free(wrapper);
95+
wrapper->watcher = NULL;
96+
napi_value result;
97+
napi_get_boolean(env, closed_ok, &result);
98+
return result;
99+
}
100+
101+
/* Opens a watcher on a path (and any children).
102+
Calls the provided callback when events happen.
103+
Accepts two arguments, a path and a callback.
104+
Returns an object with a single method: close.
105+
Call `.close()` when you don't want to watch
106+
things anymore. */
107+
static napi_value watch(napi_env env, napi_callback_info func_arg_info)
108+
{
109+
size_t argc = 2;
110+
napi_value args[2];
111+
napi_get_cb_info(env, func_arg_info, &argc, args, NULL, NULL);
112+
if (argc != 2) {
113+
napi_throw_error(env, NULL, "Wrong number of arguments");
114+
return NULL;
115+
}
116+
char path[4096];
117+
size_t path_len;
118+
napi_get_value_string_utf8(env, args[0], path, sizeof(path), &path_len);
119+
WatcherWrapper* wrapper = (WatcherWrapper*)malloc(sizeof(WatcherWrapper));
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napi_value js_callback = args[1];
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napi_create_reference(env, js_callback, 1, &wrapper->js_callback_ref);
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napi_value work_name;
123+
napi_create_string_utf8(env, "Watcher", NAPI_AUTO_LENGTH, &work_name);
124+
size_t work_queue_size = 1024;
125+
napi_create_threadsafe_function(
126+
env,
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js_callback,
128+
NULL,
129+
work_name,
130+
work_queue_size,
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1,
132+
wrapper,
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NULL,
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NULL,
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callback_js_receiver,
136+
&wrapper->tsfn);
137+
wrapper->watcher = wtr_watcher_open(path, callback_bridge, wrapper);
138+
if (wrapper->watcher == NULL) {
139+
napi_throw_error(env, NULL, "Failed to open watcher");
140+
return NULL;
141+
}
142+
napi_value watcher_obj;
143+
napi_create_object(env, &watcher_obj);
144+
napi_value close_func;
145+
napi_create_function(env, "close", NAPI_AUTO_LENGTH, close, wrapper, &close_func);
146+
napi_set_named_property(env, watcher_obj, "close", close_func);
147+
napi_wrap(env, watcher_obj, wrapper, NULL, NULL, NULL);
148+
return watcher_obj;
149+
}
150+
151+
/* Module initialization. (Does this work as a non-CommonJS module?) */
152+
static napi_value mod_init(napi_env env, napi_value exports)
153+
{
154+
napi_value watch_func;
155+
napi_create_function(env, NULL, 0, watch, NULL, &watch_func);
156+
napi_set_named_property(env, exports, "watch", watch_func);
157+
return exports;
158+
}
159+
160+
NAPI_MODULE(NODE_GYP_MODULE_NAME, mod_init)

‎watcher-nodejs/example-usage.js

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const watcher = require('./build/Debug/watcher');
2+
3+
const path = process.argv[2] || '.';
4+
var w = watcher.watch(path, (event) => {
5+
console.log(event);
6+
});
7+
8+
process.stdin.resume();
9+
process.stdin.on('data', () => {
10+
w.close();
11+
process.exit();
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});

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