From 52d31963e19d617462689f39b72b06fd28136ea1 Mon Sep 17 00:00:00 2001
From: Jeff Elsloo <elsloo@users.noreply.github.com>
Date: Mon, 10 May 2021 11:03:34 -0600
Subject: [PATCH 1/2] Adds new TS API TSHttpTxnCacheDiskPathGet (#7783)

* Adds new TS API TSHttpTxnCacheDiskPathGet to obtain the path of the disk that contains the requested object.

* * Modified API to return path instead of taking a double pointer argument

* * Modified TSHttpTxnCacheDiskPathGet to take a length argument that is set to the length of the returned string

* * Added a check for length being set to nullptr

(cherry picked from commit 7d60962600e0de5331c0c8bbfbedf215b3056d04)
---
 include/ts/ts.h                |  1 +
 iocore/cache/I_Cache.h         |  6 ++++++
 iocore/cache/P_CacheInternal.h | 10 ++++++++++
 proxy/http/HttpCacheSM.h       | 12 ++++++++++++
 src/traffic_server/InkAPI.cc   | 29 +++++++++++++++++++++++++++++
 5 files changed, 58 insertions(+)

diff --git a/include/ts/ts.h b/include/ts/ts.h
index a74f65ce145..a6f17af43fa 100644
--- a/include/ts/ts.h
+++ b/include/ts/ts.h
@@ -2486,6 +2486,7 @@ tsapi TSReturnCode TSHttpTxnCacheLookupStatusSet(TSHttpTxn txnp, int cachelookup
 tsapi TSReturnCode TSHttpTxnCacheLookupUrlGet(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc obj);
 tsapi TSReturnCode TSHttpTxnCacheLookupUrlSet(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc obj);
 tsapi TSReturnCode TSHttpTxnPrivateSessionSet(TSHttpTxn txnp, int private_session);
+tsapi const char *TSHttpTxnCacheDiskPathGet(TSHttpTxn txnp, int *length);
 tsapi int TSHttpTxnBackgroundFillStarted(TSHttpTxn txnp);
 tsapi int TSHttpTxnIsWebsocket(TSHttpTxn txnp);
 
diff --git a/iocore/cache/I_Cache.h b/iocore/cache/I_Cache.h
index d38716a45b0..0586d8c23d7 100644
--- a/iocore/cache/I_Cache.h
+++ b/iocore/cache/I_Cache.h
@@ -205,6 +205,12 @@ struct CacheVConnection : public VConnection {
     return -1;
   }
 
+  virtual const char *
+  get_disk_path() const
+  {
+    return nullptr;
+  }
+
   /** Test if the VC can support pread.
       @return @c true if @c do_io_pread will work, @c false if not.
   */
diff --git a/iocore/cache/P_CacheInternal.h b/iocore/cache/P_CacheInternal.h
index 70f670537d8..68714b55c0b 100644
--- a/iocore/cache/P_CacheInternal.h
+++ b/iocore/cache/P_CacheInternal.h
@@ -293,6 +293,16 @@ struct CacheVC : public CacheVConnection {
     return -1;
   }
 
+  const char *
+  get_disk_path() const override
+  {
+    if (vol && vol->disk) {
+      return vol->disk->path;
+    }
+
+    return nullptr;
+  }
+
   bool
   is_compressed_in_ram() const override
   {
diff --git a/proxy/http/HttpCacheSM.h b/proxy/http/HttpCacheSM.h
index 9add57fa26a..29a66ae144d 100644
--- a/proxy/http/HttpCacheSM.h
+++ b/proxy/http/HttpCacheSM.h
@@ -138,6 +138,18 @@ class HttpCacheSM : public Continuation
     return cache_read_vc ? (cache_read_vc->get_volume_number()) : -1;
   }
 
+  const char *
+  get_disk_path()
+  {
+    if (cache_read_vc) {
+      return cache_read_vc->get_disk_path();
+    } else if (cache_write_vc) {
+      return cache_write_vc->get_disk_path();
+    }
+
+    return nullptr;
+  }
+
   inline void
   abort_read()
   {
diff --git a/src/traffic_server/InkAPI.cc b/src/traffic_server/InkAPI.cc
index ef495cb3d11..95e7cb85681 100644
--- a/src/traffic_server/InkAPI.cc
+++ b/src/traffic_server/InkAPI.cc
@@ -5551,6 +5551,35 @@ TSHttpTxnIsWebsocket(TSHttpTxn txnp)
   return sm->t_state.is_websocket;
 }
 
+const char *
+TSHttpTxnCacheDiskPathGet(TSHttpTxn txnp, int *length)
+{
+  sdk_assert(sdk_sanity_check_txn(txnp) == TS_SUCCESS);
+
+  HttpSM *s         = reinterpret_cast<HttpSM *>(txnp);
+  HttpCacheSM *c_sm = &(s->get_cache_sm());
+
+  if (!c_sm) {
+    if (length != nullptr) {
+      *length = 0;
+    }
+
+    return nullptr;
+  }
+
+  const char *path = c_sm->get_disk_path();
+
+  if (length != nullptr) {
+    if (path != nullptr) {
+      *length = strlen(path);
+    } else {
+      *length = 0;
+    }
+  }
+
+  return path;
+}
+
 TSReturnCode
 TSHttpTxnCacheLookupUrlGet(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc obj)
 {

From bb6657bab6dac70338bbc336a43972bf6fddd81d Mon Sep 17 00:00:00 2001
From: "Alan M. Carroll" <amc@apache.org>
Date: Mon, 10 May 2021 18:30:08 -0500
Subject: [PATCH 2/2] TSHttpTxnCacheDiskPathGet - tighten up the code a bit.
 (#7806)

(cherry picked from commit 5c39528d2b8e06145cb4fa4ccd0579714cf490b8)
---
 src/traffic_server/InkAPI.cc | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/src/traffic_server/InkAPI.cc b/src/traffic_server/InkAPI.cc
index 95e7cb85681..09a6bd0ab60 100644
--- a/src/traffic_server/InkAPI.cc
+++ b/src/traffic_server/InkAPI.cc
@@ -5556,25 +5556,14 @@ TSHttpTxnCacheDiskPathGet(TSHttpTxn txnp, int *length)
 {
   sdk_assert(sdk_sanity_check_txn(txnp) == TS_SUCCESS);
 
-  HttpSM *s         = reinterpret_cast<HttpSM *>(txnp);
-  HttpCacheSM *c_sm = &(s->get_cache_sm());
-
-  if (!c_sm) {
-    if (length != nullptr) {
-      *length = 0;
-    }
+  HttpSM *sm       = reinterpret_cast<HttpSM *>(txnp);
+  char const *path = nullptr;
 
-    return nullptr;
+  if (HttpCacheSM *c_sm = &(sm->get_cache_sm()); c_sm) {
+    path = c_sm->get_disk_path();
   }
-
-  const char *path = c_sm->get_disk_path();
-
-  if (length != nullptr) {
-    if (path != nullptr) {
-      *length = strlen(path);
-    } else {
-      *length = 0;
-    }
+  if (length) {
+    *length = path ? strlen(path) : 0;
   }
 
   return path;