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feature/android de0e0939f01 2/2: Update Android port
From: |
Po Lu |
Subject: |
feature/android de0e0939f01 2/2: Update Android port |
Date: |
Thu, 27 Jul 2023 10:00:59 -0400 (EDT) |
branch: feature/android
commit de0e0939f01a747b8201e06bda5cd50dfa95187f
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>
Update Android port
* doc/emacs/android.texi (Android Document Providers): Improve
wording of paragraph clarifying limits on subprocesses.
* java/org/gnu/emacs/EmacsService.java (getDocumentTrees): Use
Java standard US-ASCII coding standard instead of the
undocumented ``ASCII'' alias.
(decodeFileName): Remove unused function.
(documentIdFromName):
* src/android.c (android_init_emacs_service): Take a String for
NAME instead of a byte array.
* src/androidvfs.c (android_verify_jni_string): New function.
(android_document_id_from_name): Verify that STRING is a valid
Modified UTF-8 string.
---
doc/emacs/android.texi | 11 +++---
java/org/gnu/emacs/EmacsService.java | 34 +++-------------
src/android.c | 3 +-
src/androidvfs.c | 75 ++++++++++++++++++++++++++++++++++--
4 files changed, 85 insertions(+), 38 deletions(-)
diff --git a/doc/emacs/android.texi b/doc/emacs/android.texi
index 1f32fdfc1d2..b86c71cea49 100644
--- a/doc/emacs/android.texi
+++ b/doc/emacs/android.texi
@@ -298,11 +298,12 @@ subsequently made available within a new directory named
a unique identifier assigned to the directory by the document
provider.
- Because these directories do not exist within the Unix file-system,
-sub-processes cannot be created within them, just as with the
-@file{/assets} directory (@pxref{Android File System}.) In addition,
-although Emacs can normally write and create files inside these
-directories, it cannot create symlinks or hard links.
+ The same limitations applied to the @file{/assets} directory
+(@pxref{Android File System}) are applied when creating sub-processes
+within those directories, because they do not exist within the Unix
+file-system. In addition, although Emacs can normally write and
+create files inside these directories, it cannot create symlinks or
+hard links.
@c TODO: fix this!
Since document providers are allowed to perform expensive network
diff --git a/java/org/gnu/emacs/EmacsService.java
b/java/org/gnu/emacs/EmacsService.java
index 6059439551f..bc62e050345 100644
--- a/java/org/gnu/emacs/EmacsService.java
+++ b/java/org/gnu/emacs/EmacsService.java
@@ -1282,7 +1282,7 @@ public final class EmacsService extends Service
try
{
- providerName = new String (provider, "ASCII");
+ providerName = new String (provider, "US-ASCII");
}
catch (UnsupportedEncodingException exception)
{
@@ -1306,24 +1306,6 @@ public final class EmacsService extends Service
return treeList.toArray (new String[0]);
}
- /* Decode the specified STRING into a String object using the UTF-8
- format. If an exception is thrown, return null. */
-
- private String
- decodeFileName (byte[] string)
- {
- try
- {
- return new String (string, "UTF-8");
- }
- catch (Exception e) /* UnsupportedEncodingException, etc. */
- {
- ;;
- }
-
- return null;
- }
-
/* Find the document ID of the file within TREE_URI designated by
NAME.
@@ -1342,11 +1324,10 @@ public final class EmacsService extends Service
If the designated file can't be located, return -1. */
private int
- documentIdFromName (String tree_uri, byte name[],
- String[] id_return)
+ documentIdFromName (String tree_uri, String name, String[] id_return)
{
Uri uri, treeUri;
- String nameString, id, type;
+ String id, type;
String[] components, projection;
Cursor cursor;
int column;
@@ -1360,11 +1341,8 @@ public final class EmacsService extends Service
/* Parse the URI identifying the tree first. */
uri = Uri.parse (tree_uri);
- /* Next, decode NAME. */
- nameString = decodeFileName (name);
-
/* Now, split NAME into its individual components. */
- components = nameString.split ("/");
+ components = name.split ("/");
/* Set id and type to the value at the root of the tree. */
type = id = null;
@@ -1462,7 +1440,7 @@ public final class EmacsService extends Service
try
{
- nameString = cursor.getString (column);
+ name = cursor.getString (column);
}
catch (Exception exception)
{
@@ -1473,7 +1451,7 @@ public final class EmacsService extends Service
/* Break out of the loop only once a matching component is
found. */
- if (nameString.equals (component))
+ if (name.equals (component))
break;
}
diff --git a/src/android.c b/src/android.c
index d8b264a8491..098fa6c383d 100644
--- a/src/android.c
+++ b/src/android.c
@@ -1556,7 +1556,8 @@ android_init_emacs_service (void)
FIND_METHOD (get_document_trees, "getDocumentTrees",
"([B)[Ljava/lang/String;");
FIND_METHOD (document_id_from_name, "documentIdFromName",
- "(Ljava/lang/String;[B[Ljava/lang/String;)I");
+ "(Ljava/lang/String;Ljava/lang/String;"
+ "[Ljava/lang/String;)I");
FIND_METHOD (get_tree_uri, "getTreeUri",
"(Ljava/lang/String;Ljava/lang/String;)"
"Ljava/lang/String;");
diff --git a/src/androidvfs.c b/src/androidvfs.c
index bab3977ed5a..c174c35f02b 100644
--- a/src/androidvfs.c
+++ b/src/androidvfs.c
@@ -3936,6 +3936,66 @@ static struct android_vops saf_new_vfs_ops;
/* Chain of all open SAF directory streams. */
static struct android_saf_tree_vdir *all_saf_tree_vdirs;
+/* Verify that the specified NULL-terminated STRING is a valid JNI
+ ``UTF-8'' string. Return 0 if so, 1 otherwise.
+
+ The native coding system used by the JVM to store strings derives
+ from UTF-8, but deviates from it in two aspects in an attempt to
+ better represent the UCS-16 based Java String format, and to let
+ strings contain NULL characters while remaining valid C strings:
+ NULL bytes are encoded as two-byte sequences, and Unicode surrogate
+ pairs encoded as two-byte sequences are prefered to four-byte
+ sequences when encoding characters above the BMP. */
+
+static int
+android_verify_jni_string (const char *name)
+{
+ const unsigned char *chars;
+
+ chars = (unsigned char *) name;
+ while (*chars)
+ {
+ /* Switch on the high 4 bits. */
+
+ switch (*chars++ >> 4)
+ {
+ case 0 ... 7:
+ /* The 8th bit is clean, so this is a regular C
+ character. */
+ break;
+
+ case 8 ... 0xb:
+ /* Invalid starting byte! */
+ return 1;
+
+ case 0xf:
+ /* The start of a four byte sequence. These aren't allowed
+ in Java. */
+ return 1;
+
+ case 0xe:
+ /* The start of a three byte sequence. Verify that its
+ continued. */
+
+ if ((*chars++ & 0xc0) != 0x80)
+ return 1;
+
+ FALLTHROUGH;
+
+ case 0xc ... 0xd:
+ /* The start of a two byte sequence. Verify that the
+ next byte exists and has its high bit set. */
+
+ if ((*chars++ & 0xc0) != 0x80)
+ return 1;
+
+ break;
+ }
+ }
+
+ return 0;
+}
+
/* Find the document ID of the file within TREE_URI designated by
NAME.
@@ -3943,6 +4003,9 @@ static struct android_saf_tree_vdir *all_saf_tree_vdirs;
individual files. Each constituent component prior to the last
must name a directory file within TREE_URI.
+ If NAME is not correct for the Java ``modified UTF-8'' coding
+ system, return -1.
+
Upon success, return 0 or 1 (contingent upon whether or not the
last component within NAME is a directory) and place the document
ID of the named file in ID.
@@ -3965,6 +4028,12 @@ android_document_id_from_name (const char *tree_uri,
char *name,
jmethodID method;
const char *doc_id;
+ /* Verify the format of NAME. Don't allow creating files that
+ contain characters that can't be encoded in Java. */
+
+ if (android_verify_jni_string (name))
+ return -1;
+
/* First, create the array that will hold the result. */
result = (*android_java_env)->NewObjectArray (android_java_env, 1,
java_string_class,
@@ -3972,11 +4041,9 @@ android_document_id_from_name (const char *tree_uri,
char *name,
android_exception_check ();
/* Next, create the string for the tree URI and name. */
- length = strlen (name);
- java_name = (*android_java_env)->NewByteArray (android_java_env, length);
+ java_name = (*android_java_env)->NewStringUTF (android_java_env,
+ name);
android_exception_check_1 (result);
- (*android_java_env)->SetByteArrayRegion (android_java_env, java_name,
- 0, length, (jbyte *) name);
uri = (*android_java_env)->NewStringUTF (android_java_env, tree_uri);
android_exception_check_2 (result, java_name);